I understand that I am 12 years late to the party but having been a lab tech in a films company I appreciate this type of trial. One thing you could add to the trial is whats called a "cross-hatch" test which is quite aggressive but should tell immediately if there is going to be a failure. In the lab we use a cross hatch tool but you can use a razor knife and create a series of cross hatch cuts, cover them with different types of tape, allow different dwell times and then peel the tape off comparing how much finish peels off.
In the woodturning world Shellac is consider "universal finish" meaning that anything can go under or over Shellac. That has been my experience. I hope you keep this boards for at least year and give us an update. I enjoy your videos very much, thank you.
I have put multiple coats of Amber shellac on 6 panel pine doors and followed up with 2 coats of poly. While I haven't tried pulling the finish off, I can tell you after several years, the doors look wonderful. I used shellac to color the doors because that is the wood finish throughout the house.
Thank you! Your testimonial is good enough for me to try it. I am applying it to what I believe to be pre-select brick. I will just check to see which has a better heat resistance because the brick surrounds the stove.
I used 1 coat of Shellac under 3 topcoats of Polyurethane on my workbench and it has held up perfectly under lots of use for close to 2 years now. I did that based on this video and have never regretted it. Thanks!
Had the nicest day today went for supplies at HD and didn't have enough, had to put the shellac back. This gentleman came up to me and gave me the shellac I had put back as a gift. I want to say thank you very much if he's from around here.
To support what Mark is showing us. I have done linseed oil, a spit coat of waxed shellac and 2 coats of water based poly all in one day with no issue what so ever - so yes it can be done!
The real test would be to expose the samples to heat and cold, like setting them in a sunny window for a while then setting them in the path of an air conditioner. The expansion and contraction might then cause the poly to lose it's bond to the waxed shellac more easily than it would the other samples. I'm thinking along the line of old house trim which has been polyurethaned over and has alligatored over the years. The original oil varnish finish is slightly gummy compared to the more brittle polyurethane, so the poly cracks up and floats around like sheets of ice on water. Of course, the old house trim would have a considerably thicker layer of finish than your samples, but just a theory I feel worth sharing.
@ironlionkalo Shellac pretty much binds to everything. That's what makes it such a great sealer. It can seal off impurities and oils in the wood, allowing your other more sensitive finishes to bind.
Thanks! I’m a baby woodworker and was alarmed at the hyperbolic naysaying about shellac under polyurethane. Thanks for your advice and exploration of the options!
Try a natural brush for oil-based poly. Keep the synthetics for water-based materials. The natural bristles will allow you to lay a smoother layer of finish. You might also try diluting a little with mineral spirits to help the finish flow a little better.
Great demo! I appreciate letting us know to use shellac under polyurethane for drying purposes. Usually I am waiting ten hours to put the second coat on and your first coat over the shellac looked great.
If you want a shellac finish, you can certainly use that over the stain. I wouldn't recommend staining after the shellac application unless you cut the shellac by quite a bit first. Shellac will seal the surface and prevent the stain from absorbing as much as it would in raw wood.
The Wood Whisperer I had that exact question and now it’s answered. Making a lazy Susan and want to seal it , but want to stain first. Now your non waxed says it’s sanding sealer, is that still shellac?
I was wondering would this work on a Redwood fence that would be in the sun? My friend turned me on to this video...should I put the Shellac on first then my stain, then Shellac again?
we used shellac as a sealer on stained oak staircase, then put 2 coats of oil based poly. We had major issues with that staircase's finish, cracking, peeling. So yes indeed waxed shellac under oil poly does certainly cause issues in the trade.
@@phantomcreamer I think the difference is that he was using a water-based polyurethane in this video and the man used in oil based polyurethane on the staircase
I recently saw your other video about shellac and stain vs gel stain. This info is so useful. I'm planning to apply stain to some 100 year old pine and poplar repurposed from an old piece of furniture. Thanks very much for your videos!
@boostz32 Personally I think its probably. But ultimately, its probably not worth the risk. Although I made this video to challenge the assumptions out there, when it comes to finishing my furniture, its not a place where I'm going to take a needless risk. So honestly, I only stock up on dewaxed shellac just to make sure I never have a problem. So unless you have a particular need/reason to use waxy shellad, I'd play it safe and go dewaxed.
I totally get what you mean by testing results for the way you would use it. Just to add to the mix, I did floor sanding/refinishing for years and do wood turning now. We could tell if any wax had hit the floor (even overspray from a can of Pledge) because the urethane would wrinkle immediately. But I use the regular shellac, cut, as one of my sealers for turning without any issues.
The one thing I could think could cause some problems having shellac under the poly would be in a very specific situation. First we would need to have a thicker layer of the shellac under the poly and second long exposure to temperature differences, given that the shellac layer is thick enough to expand so different from the poly that would eventually peel, but than again any other type of varnish over shellac would do the same thing... man this is the reason I watch your channel all the time, very clever thinking. Thanks for the video!
I sure hope that you are right because I just did a floor with poly over natural shellac. In a week or so I may even do the duct tape test as you did. Love your vid !
12 years late. But, there IS a difference between waxed and non-waxed shellac when you're applying stain (as opposed to poly). You get a much more even coverage of stain with the non-waxed shellac. I've done with this with cherry a number of times. In each case, I seem to get more even coverage of the stain with the NON-waxed shellac, then I cover the stain with a top coat. In my case, Arm-R-Seal. Thanks for the tips, Mark. You got me started down this wonderful road. Much appreciated.
recently finished a partscaster guitar...used bullseye amber shellac on a maple body to match the color of the neck..the neck was a gloss finish the shellac was not the same gloss..which i wanted..so rather than start over i used the hand rubbed gloss poly over the shellac..it turned out great and 2 months later no negative signs...quick tip..for a yellow/honey/gold finish..i gave the guitar a yellow stain first..then the amber shellac..it turns out great the way the yellow underneath shows thru the amber..thanks for this video..i'd never have tried it until i saw this..
Shellac can be a sealer or a topcoat. But as a topcoat, it isn't quite as protective as some may want. Poly, on the other hand, is. So we often seal with shellac and follow up with a more durable topcoat.
The way I was taught to test for adhesion problems is to score and X into the finish with a sharp knife. Then press a piece of tape down firmly over the X and yank it off quickly.
Exactly as you wrote. The presentation showed nothing without a cross-hatch adhesion test. Absent such a test, the presented information has little value in helping us to select and choose the right finish.
I have used zinzer shelac over various brands of gell stain that were brushed on and left to dry instead of wiping it all off, then finished with waterbase Varathane . I've done it this way for many years. My wife does the stripping and staining and I had to come up with something to make her method work. I have a large house full of beautiful re finished thrift store furniture that says this works just fine. You do have to make sure the stain and then the shelac are more than thoroughly dry or your going to be re stripping and starting over. Shelac over minwax gel stain is difficult, old masters gell stain is good, i've put Varathane directly over it once or twice but I only use the shelac in between anymore. Try a test piece before you do a big area.
The guy at the paint shop hands me a quart of shellac and a quart of poly to treat my stained t&g. Says "this is what you need". Great. He should know. That's all he does. I get home. Read the labels and it tells me the exact opposite. Chit. I think maybe someone on the youtube tested this out. Sure enough. Many thanks to you woodwisperer.
Having used shellac under urethane for over 30 years I can tell you I have not had issues. If you are unsure the use varnish over the shellac then urethane if you like. Personally, I like the look of varnish over shellac buffed to a matte finish as it is the least cloudy of them all.
Just built a coffee table from reclaimed old-growth doug fir. Did multiple coats of unwaxed shellac for color and depth, and then 4 coats of minwax whipe-on poly for toughness. Looks so so so good. Just one example of why someone would use poly in a thick layer under poly.
I recommend doing this test on a contoured piece. Maybe a spindle or even a newel post. Maybe the adhesion comes into play on the edges. Then apply your tape across an edge. The flat board test is pretty much your optimal situation and rarely is that the extent of a finishing project. I appreciate your sharing this!
I've tried using Shellac tinted with stains on guitars. I've applied a few coats of shellac until I got the colour I was after. Then sprayed a protective layer of acrylic spray paint. It does adhere somewhat, as long as there's no pressure on the finish. Where I've applied pressure (like screwing in pickup rings, tuners etc), that's where the finish will unbind from each other. It may have also been not allowing the shellac to dry for long enough (I can't remember how long I left it, but I'm sure it was only a few days at most). Could be the stain not allowing adhesion.
@Shannariano Haven't done any impact testing. But I did do further adhesion testing using a Scotch tape test. I used an x-acto knife to create a grid of cuts and then put the tape over top of that. Neither duct tape or scotch tape could pull up any finish.
Thanks. Your informative video saves me, as a total amateur, time and anguish over something that probably doesn't matter. But I enjoy the hobby. Even my wife had to laugh at measuring cups appropriation for the greater good.
just finished a guitar build..used oil based stain on the body in a tan color..the neck was the vintage yellow/orange color and did not look good with the body color...so instead of sanding and restaining the body , i put about 3 coats of zinsser amber shellac over the body after i gave it a light sanding with 400 grit...well thank God the amber shellac added just the right touch of yellowish/orange color that the body now goes perfectly with the neck...i also love the fast drying time of the shellac...i did not check for compatibility of shellac over oil based stain...but so far so good.
I like the way you covered this, it made sense to me. I too would like to see more on the subject of spraying finishes rather than brushed. You do a great job and its probably only a matter of time before you're picked up by a big network, Norm..., er, uh, Marc. I'll be checking more videos out, I will be making an end grain cutting board soon. -Ken
Good video.. I have been using 50/50 (shellac/alchohol) on many different woods for many years. I have one piece of furniture I built for our own use about 25 yrs. ago. 50/50 to seal and pull up any loose wood fibers and 3 sprayed on coats of poly. It looks the same as it did when I made it. BTW white oak. I have to assume it is a CYA ploy on the part of the maker of the pollyurethane. Like you I am a bit mystified. Thanks for the tests.
I am a experienced home painter of 22 years. I have done many kitchen cabinets over the years. I have seen one fail. I tried a water-based varnish and found out that (when lightsanding) the varnish came off in flakes. It was clear that it was shalac. After 220 grit sanding the whole thing and cleaning with alcohol. I went out and got a oil based varnish and everthing was fine. I just resently ran into that customer and there has been no issues so far. I did that in 2002. I have had issues since.
Yes you can. Shellac is nearly always a good idea as a barrier coat. But if the surface is fully cured, after a light sanding and wipe-down with something like denatured alcohol, you should be able to put down lacquer immediately and skip the shellac. But always test for adhesion issues in an inconspicuous area.
hey hey hey, the wood whisperer - i bought a butcher block round maple table from craig's list a few months ago. it had what-i-think-was polyurethane that had orange peeled and chipped - so i sanded it down with 80-220 paper and now need to stain and finish it. i have looked on youtube on how to approach it and am overwhelmed with the options. so then i put an ad on craig's list looking for someone who could finish it, because i figured it was too much for a DIY homeowner. what are your thoughts and do you have a video about water-based poly? i want to stain the table a dark color, i think with a satin poly on top of it.
Sure. But it's probably a little overkill to sand with 2000 each time. I'd sand with maybe 400-600 until the final coat or two, then switch to 1000-2000.
Well its value in blotch control and oily woods is well-documented. Just do a few searches for info on that. As for saving time, you can use shellac as your first coat of finish and you'll be ready to apply your first coat of oil-based poly within an hour or so, as opposed to applying the oil-based poly first and waiting a day for it to dry.
Some problems only occur under certain conditions. Once a customer wanted the wood to be finished with a particular top-layers, so that the look and feel, and the gloss was the same as other wood. Some products of some brands have more solvents in them then others, sometimes the solvent of the top-layers is re-solving the layers already on the wood. But if only a very thin coat is being applied there is nothing to worry about.
A standard way of testing the bond is to score an x with a sharp knife, then press some tape over the x. Give it a quick yank of the surface and see if the coating is peeled.
You know it's guys like you and Stuby Nubs that separate all the Hype from facts and truths. You are right on. I have used all kinds of finishes on all kinds of woods and NEVER have I had the problems that you have exposed in this simple test. I do agree with you that there must be Some Kind of Condition that allows such statements of failure but as a general rule they are far and few between..THANKS FOR THE TEST
Thank you for this video! I just put spray poly over OBShine Juice... 1 part shellac, 1 part denatured alcohol, and 1 part boiled linseed oil... On a turned pecan wood bowl... So far so good!
@Xar0mir I wouldn't really count on the glue doing anything productive to a finish. So damaged or not, I wouldn't recommend using epoxy on the surface.
I once had a can of that Zinsser Shellac Sealcoat eat through the bottom of its own can and spill onto my cabinet. It did the opposite of a great finishing product. Suggest you decant into glass bottles for storage.
Well, that's definitely not my favorite way to change color. It almost always ends up less attractive that one would hope. If the surface is properly prepped, you might be able to get away with polyshades. I have also hear of some folks using a gel stain and then coming back with another clear coat on top.
About five weeks ago, I finished the plywood surface of a new workbench with two coats of white shellac, followed by two coats of Minwax semi-gloss poly. So far, absolutely no sign of adhesion problems. I've used poly over spit coats of shellac for years and never heard that we shouldn't use poly over shellac. In my case, time will tell I guess, but hey, it's a workbench! I If it does start shedding off, we'll strip it and refinish.
@TheWoodWhisperer I just thought it was great that someone actually took the time to test it and share the results. A fine job you did of it. But after careful consideration I opted to skip the shellac and just use several coats of poly. I treated the cedar with a pre-stain conditioner before staining so shellac would be overkill. I'm still waiting for the stain to settle so if this is a bad idea I'm all eyes.
Hi Marc. Do you see any issue using shellac under water based poly? I make a bunch of cornhole boards and am thinking that a coat of shellac could save a few coats of poly. As usual thanks for all the videos!
Thanks for the video Marc, I've found the same results in my experiences. Have you gone back to see if these boards ever dissolved as was claimed they would do by some other commenters here?
I wish I knew how to put a picture with my comment. I am not a wood whisperer BY ANY STRETCH OF THE IMAGINATION. I just piddle around the house. I removed the back seat of my 2002 dodge in 2008 and put 3/4" wood n for my 2 dogs in. I used Amber shilac and then put either polyurethane or spar urethane ( I honestly don't know the difference) I just removed it a few weeks ago and it looks great. That is 10 years in a garnet/ maroon color truck ( hot as crap in the summer) and dogs in it every day. I don't remember every step of the process I used. Maby neither of the 3 of us knew we were not supposed to work with each other and we just got the job done. Thank you for telling me that Zinzer or whoever says it would not work 😂 I promise I wouldn't tell my piece of plywood. Sometimes ignorance is bliss.
I’m trying Aqua Fortis, followed by 1 coat dewax shellac, then 2-3 coats poly - it’s for a high traffic area kitchen island and this gives me faith it might just work! Love the look of curly maple on gun stock and gonna give it a try. Thnx Mark
Just a guess at this but it may be that the light sanding removes any light skin of wax this allows for good adhesion. It may not work over a built up coat of shellac. If multiple coats of shellac are built up there is no need to put another finish on, if other finish is used just use the shellac as a wood sealer.
I'm surprised to hear that they don't recommend using it under poly finishes. I always followed the advice of "The Furniture Guy", Ed and Joe. They use a spit-coat of shellac under almost all their finishes. I made hutch 15 yrs ago with a spit-coat of shellac and alcohol, then stain, then polyurethane, It worked perfectly and is holding-up beautifully to this day.
Great video. Very much appreciated. I'm building wall and base cabinets for my basement and plan to do a seal coat of the Zinsser Sealcoat with a satin clear polyurethane topcoat for all interior surfaces. I want to do this for the inside of the cabinets so they'll not be so dark inside. For the exterior though, I'm staining the wood with Minwax Golden Oak. My question for the external is, what do I lay down on the plywood as I stain and then final coat with Polyurethane? Would I use the Zinsser Sealcoat at all on the exterior, i.e., sides, frame and doors? If so, in what order? Sealcoat, stain, poly? Thanks.
I'm working with the same three finishes right now and was asking the exact question. After seeing this I'll try the poly on the back side of cupboard doors I'm refinishing. If it works the fronts get a coat too. thanks
I watched this because I have had to use this method to put water based poly over an oil based stain on cherry trim. I was originally using the waxed shellac, and when I shot the nails into the trim boards, the poly would crack and peel up around the the area where the nail was driven in. This did not happen when I switched to the sealcoat dewaxed shellac.
A finishing expert explained to me that shellac becomes a very hard surface after drying; which severely restricts adhesion for the next different coat. Max, a couple of hours, for adding the next different coat (soonest possible best), after that the shellac fully cures and becomes too hard. If wait too long can recoat Dry shellac with more shellac (or perhaps just alcohol?). Waxed shellac was not recommended as an undercoat (adhesion & interaction problems).
Waxed shellac is great for a complete finish and would not be the best for undercoat or for cutting with other finishes. Nor would I try to dilute it with alcohol.
I really appreciate finishing as the topic here, almost can't have enough videos about the subject. I have a great book that really opened my eyes to the possibilities, "Wood Finishing with George Frank" by the late George Frank I would highly reccomend it.
I honestly don't remember exactly what I used but it was most likely just a can of wiping varnish. Significantly thinner than your regular variety of varnish, which makes it nice for wiping. Not ideal for this experiment though...but I was trying to get rid of some stuff i had in the cabinet. :) Honestly not sure on the coating thickness....sorry my friend. Maybe I should send some DD your way? Shipping wouldn't be too bad. :)
Great tutorial....personally I use the de-waxed spray can clear shellac...a light sanding and 3 coats of water poly. The shellac eliminated the grain raising of just the water based poly
I've also tried many combinations including water based polycrylic on oil based stain. It's all about drying, humidity and temperature. We know about that in MN.
I put polyurethane on a surface of a bookcase, with an unknown type of finish. The poly did not sink into the wood. It stayed on the surface and formed a soft sticky gummy coating. Even a few years later, it stayed gooey. I wound up having to scrape the goo off. It took a lot of elbow grease, solvent and patients. Most people would have tossed the bookcase away, and I thought of doing so, many times .
I appreciated the test. I have never used one finish over another but it is good to know I could. Maybe keep the test pieces and at a later date, show the results?? Good stuff! Keep it up : )
a liquid called wood knotting which is used over here in UK to stop wood knots bleeding natural wood glue under warm temperatures is Shellac based, a pretty robust sealer don't you think..
How have the pieces held up, 4 years later? I already applied waxed amber Zinsser to my guitar headstock, and I have to clear coat it with SOMETHING after I put on the waterslide decal. I bought a can of Minwax poly, not knowing.
I think the myth stems from the use of wax as a barrier when using adhesives in general. For example, When gluing wooden hinges, i apply wax to the spaces where adhesion is to be avoided when glue is applied. Perhaps it is this practice of using wax as an anti adhesive barrier where the whole deal with waxxed vs unwaxed schellac came from, although i would speculate that there was some bad experiences that led to the reinforcement of such advice.
One interesting test would be to put the duct tape and the aluminum tape over the damage caused by the epoxy damage. again, it would only show how damage can continue based off an initial damage, but that might be a factor in why people say not to do this. Great video though, Thanks!
Hi Ed, Valid Point. I have concluded my own test with shellac sanding sealer diluted in denatured alcohol 50/50 ... various spirit based stains on top followed by poly oil and water based about 8 different combinations. What I found was that the best results from durability point of view was achieved by water based stain (gel like) applied directly to wood without shellac followed by water based poly. Even if the finish is damaged with a blade the stain penetrates quite deep and will not flash the lighter wood trough the finish so it is less obvious.
I know this is an old video, and I like Ted's suggestion, but nice information to have. Wondering if you ever went back to these boards or another experiment.
I understand that I am 12 years late to the party but having been a lab tech in a films company I appreciate this type of trial. One thing you could add to the trial is whats called a "cross-hatch" test which is quite aggressive but should tell immediately if there is going to be a failure. In the lab we use a cross hatch tool but you can use a razor knife and create a series of cross hatch cuts, cover them with different types of tape, allow different dwell times and then peel the tape off comparing how much finish peels off.
If you still have those pieces lying around maybe 12 years later would be a good time to come back to it to see how well they fared.
Right, yeah. I've always understood that it creates issues with longevity. I'd be interested to see this as well.
In the woodturning world Shellac is consider "universal finish" meaning that anything can go under or over Shellac. That has been my experience. I hope you keep this boards for at least year and give us an update. I enjoy your videos very much, thank you.
Dewaxed shellac, yes. Waxed shellac, no.
I have put multiple coats of Amber shellac on 6 panel pine doors and followed up with 2 coats of poly. While I haven't tried pulling the finish off, I can tell you after several years, the doors look wonderful. I used shellac to color the doors because that is the wood finish throughout the house.
Thank you! Your testimonial is good enough for me to try it. I am applying it to what I believe to be pre-select brick. I will just check to see which has a better heat resistance because the brick surrounds the stove.
I used 1 coat of Shellac under 3 topcoats of Polyurethane on my workbench and it has held up perfectly under lots of use for close to 2 years now. I did that based on this video and have never regretted it.
Thanks!
tttenney water or oil based poly? Just curious
Just what I was looking for 😁
How's it holding up now? No issues?
Had the nicest day today went for supplies at HD and didn't have enough, had to put the shellac back. This gentleman came up to me and gave me the shellac I had put back as a gift. I want to say thank you very much if he's from around here.
What a gent, thanks for telling this story, gives you faith that there are kind people around. Hope your project turned out well
Sometimes I like to do random acts of kindness just to see the persons reaction, like is this guy of sound mind? 😆
To support what Mark is showing us. I have done linseed oil, a spit coat of waxed shellac and 2 coats of water based poly all in one day with no issue what so ever - so yes it can be done!
Mark, Thank you for this video and thank you to all the other viewers that left constructive comments. Both are greatly appreciated.
The real test would be to expose the samples to heat and cold, like setting them in a sunny window for a while then setting them in the path of an air conditioner. The expansion and contraction might then cause the poly to lose it's bond to the waxed shellac more easily than it would the other samples. I'm thinking along the line of old house trim which has been polyurethaned over and has alligatored over the years. The original oil varnish finish is slightly gummy compared to the more brittle polyurethane, so the poly cracks up and floats around like sheets of ice on water. Of course, the old house trim would have a considerably thicker layer of finish than your samples, but just a theory I feel worth sharing.
Nearly anything that is subjected to the elements will succumb to it.
Yeah I was thinking the micro movements over time due to humidity changes could weaken the bond.
@ironlionkalo Shellac pretty much binds to everything. That's what makes it such a great sealer. It can seal off impurities and oils in the wood, allowing your other more sensitive finishes to bind.
Thanks! I’m a baby woodworker and was alarmed at the hyperbolic naysaying about shellac under polyurethane. Thanks for your advice and exploration of the options!
Glad it was helpful!
Try a natural brush for oil-based poly. Keep the synthetics for water-based materials. The natural bristles will allow you to lay a smoother layer of finish. You might also try diluting a little with mineral spirits to help the finish flow a little better.
Me and 857 other viewers: "Don't brush over the Sharpie ink."
Great demo! I appreciate letting us know to use shellac under polyurethane for drying purposes. Usually I am waiting ten hours to put the second coat on and your first coat over the shellac looked great.
If you want a shellac finish, you can certainly use that over the stain. I wouldn't recommend staining after the shellac application unless you cut the shellac by quite a bit first. Shellac will seal the surface and prevent the stain from absorbing as much as it would in raw wood.
The Wood Whisperer I had that exact question and now it’s answered. Making a lazy Susan and want to seal it , but want to stain first. Now your non waxed says it’s sanding sealer, is that still shellac?
I was wondering would this work on a Redwood fence that would be in the sun? My friend turned me on to this video...should I put the Shellac on first then my stain, then Shellac again?
we used shellac as a sealer on stained oak staircase, then put 2 coats of oil based poly. We had major issues with that staircase's finish, cracking, peeling. So yes indeed waxed shellac under oil poly does certainly cause issues in the trade.
This comment wrapped up his whole video. lol
So why doesn't he have peeling and cracking? What did you do differently? Maybe no sanding between coats?
...
@Marxine St.Arline There's nothing special about how wax ages
@@phantomcreamer I think the difference is that he was using a water-based polyurethane in this video and the man used in oil based polyurethane on the staircase
I recently saw your other video about shellac and stain vs gel stain. This info is so useful. I'm planning to apply stain to some 100 year old pine and poplar repurposed from an old piece of furniture. Thanks very much for your videos!
This gave me the confidence to use shellac as a sealer. Well done.
@boostz32 Personally I think its probably. But ultimately, its probably not worth the risk. Although I made this video to challenge the assumptions out there, when it comes to finishing my furniture, its not a place where I'm going to take a needless risk. So honestly, I only stock up on dewaxed shellac just to make sure I never have a problem. So unless you have a particular need/reason to use waxy shellad, I'd play it safe and go dewaxed.
I totally get what you mean by testing results for the way you would use it. Just to add to the mix, I did floor sanding/refinishing for years and do wood turning now. We could tell if any wax had hit the floor (even overspray from a can of Pledge) because the urethane would wrinkle immediately. But I use the regular shellac, cut, as one of my sealers for turning without any issues.
The one thing I could think could cause some problems having shellac under the poly would be in a very specific situation. First we would need to have a thicker layer of the shellac under the poly and second long exposure to temperature differences, given that the shellac layer is thick enough to expand so different from the poly that would eventually peel, but than again any other type of varnish over shellac would do the same thing... man this is the reason I watch your channel all the time, very clever thinking. Thanks for the video!
I sure hope that you are right because I just did a floor with poly over natural shellac. In a week or so I may even do the duct tape test as you did. Love your vid !
12 years late. But, there IS a difference between waxed and non-waxed shellac when you're applying stain (as opposed to poly). You get a much more even coverage of stain with the non-waxed shellac. I've done with this with cherry a number of times. In each case, I seem to get more even coverage of the stain with the NON-waxed shellac, then I cover the stain with a top coat. In my case, Arm-R-Seal. Thanks for the tips, Mark. You got me started down this wonderful road. Much appreciated.
FYI. it's the UV light from artificial or sun light over time that breaks the bonds between the shellac and poly
Is it anything about that out there? I'm quite interested. Thanks
so not for outdoor use, got it!
FYI, it is UV radiation, not UV light. And a good Poly finish will actually block UV.
recently finished a partscaster guitar...used bullseye amber shellac on a maple body to match the color of the neck..the neck was a gloss finish the shellac was not the same gloss..which i wanted..so rather than start over i used the hand rubbed gloss poly over the shellac..it turned out great and 2 months later no negative signs...quick tip..for a yellow/honey/gold finish..i gave the guitar a yellow stain first..then the amber shellac..it turns out great the way the yellow underneath shows thru the amber..thanks for this video..i'd never have tried it until i saw this..
Shellac can be a sealer or a topcoat. But as a topcoat, it isn't quite as protective as some may want. Poly, on the other hand, is. So we often seal with shellac and follow up with a more durable topcoat.
The way I was taught to test for adhesion problems is to score and X into the finish with a sharp knife. Then press a piece of tape down firmly over the X and yank it off quickly.
More so for film latex finishes. paint
Exactly as you wrote. The presentation showed nothing without a cross-hatch adhesion test. Absent such a test, the presented information has little value in helping us to select and choose the right finish.
I have used zinzer shelac over various brands of gell stain that were brushed on and left to dry instead of wiping it all off, then finished with waterbase Varathane . I've done it this way for many years. My wife does the stripping and staining and I had to come up with something to make her method work. I have a large house full of beautiful re finished thrift store furniture that says this works just fine. You do have to make sure the stain and then the shelac are more than thoroughly dry or your going to be re stripping and starting over. Shelac over minwax gel stain is difficult, old masters gell stain is good, i've put Varathane directly over it once or twice but I only use the shelac in between anymore. Try a test piece before you do a big area.
The guy at the paint shop hands me a quart of shellac and a quart of poly to treat my stained t&g. Says "this is what you need". Great. He should know. That's all he does. I get home. Read the labels and it tells me the exact opposite. Chit. I think maybe someone on the youtube tested this out. Sure enough. Many thanks to you woodwisperer.
Having used shellac under urethane for over 30 years I can tell you I have not had issues.
If you are unsure the use varnish over the shellac then urethane if you like. Personally, I like the look of varnish over shellac buffed to a matte finish as it is the least cloudy of them all.
using tung oil, is the best way to seal your wood before you poly. I found that you can get a more beautiful finish and seal, by doing this
perfect answer and solution to all the questions i've been thinking about today. thank you! love your channel. Inspiring and informative.
I use sanding sealer on libraries, banks and museums. Shellac does have a good application portfolio, but it's good to follow professional directions.
Just built a coffee table from reclaimed old-growth doug fir. Did multiple coats of unwaxed shellac for color and depth, and then 4 coats of minwax whipe-on poly for toughness. Looks so so so good. Just one example of why someone would use poly in a thick layer under poly.
I recommend doing this test on a contoured piece. Maybe a spindle or even a newel post. Maybe the adhesion comes into play on the edges. Then apply your tape across an edge. The flat board test is pretty much your optimal situation and rarely is that the extent of a finishing project. I appreciate your sharing this!
You in fact did prove that polyurethane is not bullet proof but stands up well regardless of base coats. Thanks for that!
I've tried using Shellac tinted with stains on guitars. I've applied a few coats of shellac until I got the colour I was after. Then sprayed a protective layer of acrylic spray paint. It does adhere somewhat, as long as there's no pressure on the finish. Where I've applied pressure (like screwing in pickup rings, tuners etc), that's where the finish will unbind from each other. It may have also been not allowing the shellac to dry for long enough (I can't remember how long I left it, but I'm sure it was only a few days at most). Could be the stain not allowing adhesion.
I think acrylic also has a relatively long time to be fully cured, I think up to 2-4 weeks to harden 100%.
Thats a capital PYREX that is actually the borosilicate glass they don't make anymore, I will miss your content....
@Shannariano Haven't done any impact testing. But I did do further adhesion testing using a Scotch tape test. I used an x-acto knife to create a grid of cuts and then put the tape over top of that. Neither duct tape or scotch tape could pull up any finish.
The real assessment requires the test of time, the most punishing test for any wood cover.
A bright, fluent, easy to follow presentation, as usual.
Thanks. Your informative video saves me, as a total amateur, time and anguish over something that probably doesn't matter. But I enjoy the hobby. Even my wife had to laugh at measuring cups appropriation for the greater good.
just finished a guitar build..used oil based stain on the body in a tan color..the neck was the vintage yellow/orange color and did not look good with the body color...so instead of sanding and restaining the body , i put about 3 coats of zinsser amber shellac over the body after i gave it a light sanding with 400 grit...well thank God the amber shellac added just the right touch of yellowish/orange color that the body now goes perfectly with the neck...i also love the fast drying time of the shellac...i did not check for compatibility of shellac over oil based stain...but so far so good.
I like the way you covered this, it made sense to me. I too would like to see more on the subject of spraying finishes rather than brushed. You do a great job and its probably only a matter of time before you're picked up by a big network, Norm..., er, uh, Marc. I'll be checking more videos out, I will be making an end grain cutting board soon.
-Ken
Although they both have the warning about poly, the Bulleye Amber has little to no wax in it. The Bulleye Clear is the waxy one.
Good video.. I have been using 50/50 (shellac/alchohol) on many different woods for many years. I have one piece of furniture I built for our own use about 25 yrs. ago. 50/50 to seal and pull up any loose wood fibers and 3 sprayed on coats of poly. It looks the same as it did when I made it. BTW white oak. I have to assume it is a CYA ploy on the part of the maker of the pollyurethane. Like you I am a bit mystified. Thanks for the tests.
I am a experienced home painter of 22 years. I have done many kitchen cabinets over the years. I have seen one fail. I tried a water-based varnish and found out that (when lightsanding) the varnish came off in flakes. It was clear that it was shalac. After 220 grit sanding the whole thing and cleaning with alcohol. I went out and got a oil based varnish and everthing was fine. I just resently ran into that customer and there has been no issues so far. I did that in 2002. I have had issues since.
Over time its going to craze on the waxed surface . I know from working on guitars .
We’re listening ... talk on ... I’m interested in guitars and harps. Stay well and be safe.
Yes you can. Shellac is nearly always a good idea as a barrier coat. But if the surface is fully cured, after a light sanding and wipe-down with something like denatured alcohol, you should be able to put down lacquer immediately and skip the shellac. But always test for adhesion issues in an inconspicuous area.
hey hey hey, the wood whisperer - i bought a butcher block round maple table from craig's list a few months ago. it had what-i-think-was polyurethane that had orange peeled and chipped - so i sanded it down with 80-220 paper and now need to stain and finish it. i have looked on youtube on how to approach it and am overwhelmed with the options. so then i put an ad on craig's list looking for someone who could finish it, because i figured it was too much for a DIY homeowner. what are your thoughts and do you have a video about water-based poly? i want to stain the table a dark color, i think with a satin poly on top of it.
Sure. But it's probably a little overkill to sand with 2000 each time. I'd sand with maybe 400-600 until the final coat or two, then switch to 1000-2000.
Well its value in blotch control and oily woods is well-documented. Just do a few searches for info on that. As for saving time, you can use shellac as your first coat of finish and you'll be ready to apply your first coat of oil-based poly within an hour or so, as opposed to applying the oil-based poly first and waiting a day for it to dry.
Some problems only occur under certain conditions. Once a customer wanted the wood to be finished with a particular top-layers, so that the look and feel, and the gloss was the same as other wood. Some products of some brands have more solvents in them then others, sometimes the solvent of the top-layers is re-solving the layers already on the wood. But if only a very thin coat is being applied there is nothing to worry about.
A standard way of testing the bond is to score an x with a sharp knife, then press some tape over the x. Give it a quick yank of the surface and see if the coating is peeled.
You know it's guys like you and Stuby Nubs that separate all the Hype from facts and truths. You are right on. I have used all kinds of finishes on all kinds of woods and NEVER have I had the problems that you have exposed in this simple test. I do agree with you that there must be Some Kind of Condition that allows such statements of failure but as a general rule they are far and few between..THANKS FOR THE TEST
Thank you for this video! I just put spray poly over OBShine Juice... 1 part shellac, 1 part denatured alcohol, and 1 part boiled linseed oil... On a turned pecan wood bowl... So far so good!
@Xar0mir I wouldn't really count on the glue doing anything productive to a finish. So damaged or not, I wouldn't recommend using epoxy on the surface.
@EdgerHumphrey Glad to help. But make sure you test first. My little experiment here didn't really prove much. Just raised more questions. :)
Cool test! I wonder if it would have made a difference if you hasn't diluted the waxed shellac..
I once had a can of that Zinsser Shellac Sealcoat eat through the bottom of its own can and spill onto my cabinet. It did the opposite of a great finishing product. Suggest you decant into glass bottles for storage.
Yes, shellac will work as a pre-stain conditioner to prevent blotching. Test on scraps though because if you use too much, the stain won't take.
Well, that's definitely not my favorite way to change color. It almost always ends up less attractive that one would hope. If the surface is properly prepped, you might be able to get away with polyshades. I have also hear of some folks using a gel stain and then coming back with another clear coat on top.
Because it can solve several finishing issues and can cut an entire day out of the finishing process.
I’ve heard that shellac darkens over time. Is it true?
@boyzwithboardz Should be just fine. And it should definitely help your poly build faster.
About five weeks ago, I finished the plywood surface of a new workbench with two coats of white shellac, followed by two coats of Minwax semi-gloss poly. So far, absolutely no sign of adhesion problems. I've used poly over spit coats of shellac for years and never heard that we shouldn't use poly over shellac. In my case, time will tell I guess, but hey, it's a workbench! I If it does start shedding off, we'll strip it and refinish.
@EdgerHumphrey I think you'll be fine with the poly only. Always simplify the process whenever possible.
@TheWoodWhisperer I just thought it was great that someone actually took the time to test it and share the results. A fine job you did of it. But after careful consideration I opted to skip the shellac and just use several coats of poly. I treated the cedar with a pre-stain conditioner before staining so shellac would be overkill. I'm still waiting for the stain to settle so if this is a bad idea I'm all eyes.
Hi Marc. Do you see any issue using shellac under water based poly? I make a bunch of cornhole boards and am thinking that a coat of shellac could save a few coats of poly. As usual thanks for all the videos!
Great post. BTW, I also noticed that the Bulls Eye wax shellac says “DO NOT THIN” so you broke two “rules “ in your experiment. I love it!
Thanks for the video Marc, I've found the same results in my experiences. Have you gone back to see if these boards ever dissolved as was claimed they would do by some other commenters here?
I wish I knew how to put a picture with my comment. I am not a wood whisperer BY ANY STRETCH OF THE IMAGINATION. I just piddle around the house. I removed the back seat of my 2002 dodge in 2008 and put 3/4" wood n for my 2 dogs in. I used Amber shilac and then put either polyurethane or spar urethane ( I honestly don't know the difference) I just removed it a few weeks ago and it looks great. That is 10 years in a garnet/ maroon color truck ( hot as crap in the summer) and dogs in it every day. I don't remember every step of the process I used. Maby neither of the 3 of us knew we were not supposed to work with each other and we just got the job done. Thank you for telling me that Zinzer or whoever says it would not work 😂 I promise I wouldn't tell my piece of plywood. Sometimes ignorance is bliss.
I’m trying Aqua Fortis, followed by 1 coat dewax shellac, then 2-3 coats poly - it’s for a high traffic area kitchen island and this gives me faith it might just work! Love the look of curly maple on gun stock and gonna give it a try. Thnx Mark
hi there, wandering if you have used linseed oils then use shelak to seal and laker on top ,
Just a guess at this but it may be that the light sanding removes any light skin of wax this allows for good adhesion. It may not work over a built up coat of shellac. If multiple coats of shellac are built up there is no need to put another finish on, if other finish is used just use the shellac as a wood sealer.
I'm surprised to hear that they don't recommend using it under poly finishes.
I always followed the advice of "The Furniture Guy", Ed and Joe. They use a spit-coat of shellac under almost all their finishes. I made hutch 15 yrs ago with a spit-coat of shellac and alcohol, then stain, then polyurethane, It worked perfectly and is holding-up beautifully to this day.
That's because their dewaxed is about 50% more expensive.
Great video. Very much appreciated. I'm building wall and base cabinets for my basement and plan to do a seal coat of the Zinsser Sealcoat with a satin clear polyurethane topcoat for all interior surfaces. I want to do this for the inside of the cabinets so they'll not be so dark inside. For the exterior though, I'm staining the wood with Minwax Golden Oak. My question for the external is, what do I lay down on the plywood as I stain and then final coat with Polyurethane? Would I use the Zinsser Sealcoat at all on the exterior, i.e., sides, frame and doors? If so, in what order? Sealcoat, stain, poly? Thanks.
Your videos are so awesome!!! You take a very systematic approach.
@MoltenMozzarella It might slow it down, but nothing will really stop it.
I'm working with the same three finishes right now and was asking the exact question. After seeing this I'll try the poly on the back side of cupboard doors I'm refinishing. If it works the fronts get a coat too. thanks
I watched this because I have had to use this method to put water based poly over an oil based stain on cherry trim. I was originally using the waxed shellac, and when I shot the nails into the trim boards, the poly would crack and peel up around the the area where the nail was driven in. This did not happen when I switched to the sealcoat dewaxed shellac.
Proved it to me. Handy to know, thanks. Usual story, good prep wins!
It's oil-based poly.
A finishing expert explained to me that shellac becomes a very hard surface after drying; which severely restricts adhesion for the next different coat. Max, a couple of hours, for adding the next different coat (soonest possible best), after that the shellac fully cures and becomes too hard. If wait too long can recoat Dry shellac with more shellac (or perhaps just alcohol?). Waxed shellac was not recommended as an undercoat (adhesion & interaction problems).
Waxed shellac is great for a complete finish and would not be the best for undercoat or for cutting with other finishes. Nor would I try to dilute it with alcohol.
I really appreciate finishing as the topic here, almost can't have enough videos about the subject. I have a great book that really opened my eyes to the possibilities, "Wood Finishing with George Frank" by the late George Frank I would highly reccomend it.
I honestly don't remember exactly what I used but it was most likely just a can of wiping varnish. Significantly thinner than your regular variety of varnish, which makes it nice for wiping. Not ideal for this experiment though...but I was trying to get rid of some stuff i had in the cabinet. :) Honestly not sure on the coating thickness....sorry my friend. Maybe I should send some DD your way? Shipping wouldn't be too bad. :)
Great tutorial....personally I use the de-waxed spray can clear shellac...a light sanding and 3 coats of water poly. The shellac eliminated the grain raising of just the water based poly
I don't know that there is a best as folks have success with wiping, brushing, and spraying. But I personally prefer the wiping method.
Thanks for posting this! I am mid-project and ran into this very frustrating question. I will go ahead with the Poly then. Thanks again!
I've also tried many combinations including water based polycrylic on oil based stain. It's all about drying, humidity and temperature. We know about that in MN.
I put polyurethane on a surface of a bookcase, with an unknown type of finish. The poly did not sink into the wood. It stayed on the surface and formed a soft sticky gummy coating. Even a few years later, it stayed gooey. I wound up having to scrape the goo off. It took a lot of elbow grease, solvent and patients. Most people would have tossed the bookcase away, and I thought of doing so, many times .
If the previous finish had cured, then the error must have been in the new coat. Nothing would do that to poly if fully cured.
I appreciated the test. I have never used one finish over another but it is good to know I could. Maybe keep the test pieces and at a later date, show the results?? Good stuff! Keep it up : )
Why worry about this ? Same company sells clear shellac at the same price. No warning for polyurethane use and its the same price in my home center.
a liquid called wood knotting which is used over here in UK to stop wood knots bleeding natural wood glue under warm temperatures is Shellac based, a pretty robust sealer don't you think..
@RCShadow will do!
How have the pieces held up, 4 years later? I already applied waxed amber Zinsser to my guitar headstock, and I have to clear coat it with SOMETHING after I put on the waterslide decal. I bought a can of Minwax poly, not knowing.
I think the myth stems from the use of wax as a barrier when using adhesives in general. For example, When gluing wooden hinges, i apply wax to the spaces where adhesion is to be avoided when glue is applied. Perhaps it is this practice of using wax as an anti adhesive barrier where the whole deal with waxxed vs unwaxed schellac came from, although i would speculate that there was some bad experiences that led to the reinforcement of such advice.
Since shellac is bad at protecting against a mug of hot coffee, would have liked to see if the poly increased protection in this regard.
@wakeboarderblunt Yeah I don't know. I think the epoxy test was a bust simply because all it told us was not to get epoxy on our furniture. :)
One interesting test would be to put the duct tape and the aluminum tape over the damage caused by the epoxy damage. again, it would only show how damage can continue based off an initial damage, but that might be a factor in why people say not to do this. Great video though, Thanks!
You didn't address the real reason people use shellac: too avoid blotching after staining with soft woods when the poly is applied.
Hi Ed,
Valid Point. I have concluded my own test with shellac sanding sealer diluted in denatured alcohol 50/50 ... various spirit based stains on top followed by poly oil and water based about 8 different combinations. What I found was that the best results from durability point of view was achieved by water based stain (gel like) applied directly to wood without shellac followed by water based poly. Even if the finish is damaged with a blade the stain penetrates quite deep and will not flash the lighter wood trough the finish so it is less obvious.
Dude, to eliminate
blotchiness a pre stain sealer is used.
I know this is an old video, and I like Ted's suggestion, but nice information to have. Wondering if you ever went back to these boards or another experiment.