Are glue in bolts dangerous if the hole is dirty?
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- Äas pĆidĂĄn 21. 08. 2024
- Clean holes before installing glue in bolts! We did break tests that contradict that but you should still do it.
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Loved the video, for future concrete pours for testing in tension, consider using fiberglass fibers mixed in. Itâll save a lot more surface area for more testing
Im in the construction trade in Jackson Wy. I have a decent back ground in climbing big walls. I found this video pretty neat and shared it with a bunch of guys at work. Most times when we have to hilti and add all thread/epoxy to concrete we have to have a 3rd party engineer watch us do it. Making sure we have the spec depth, properly cleaned the holes, and correctly mixed/applied the epoxy. The slow motion aspect of being able to see the concrete break is awesome! Thatâs wild you hit 44 KN with that much dust!
Appreciate the video, and the willingness to throw your opinion out there.
I don't even climb and I can't seem to get enough of these videos, after accidentally finding the channel a few days ago.
I work with precast concrete this is a really good example of what's called a pullout cone
Appreciate all the effort you guys spend. And just to say it again, yes we should clean our holes! I just recently pulled a Petzl glue-in at the top of a pit in a cave nearby. Clearly that hole was NOT cleaned. 2K that doesn't not harden is a no go! Chek the best before date on your stuff! Especially if you're not bolting stuff regularly. Stay safe everyone!
If it doesnât harden, isnât it more likely that it was the early, not properly mixed section of the glue?
Thanks for the testing information. I've epoxied hundreds of holes over the years and was taught that a key to strong epoxy bolts (besides a clean hole) is not having voids in the epoxy. The following process works well: be sure to let the mixing tip fill with epoxy before you insert it into the hole, so you know it is ready to come out immediately. Insert the mixing tip all the way into the hole and fill the hole from the far end outward. Try to keep an even pace when filling the hole and removing the tip. Maybe this could be another line of testing: do voids cause major weakness.
we can try testing air pockets and how much they weaken bolts
Wow, those results were surprising. I would still feel better if the holes were cleaned properly. But dayum those results were way higher then I thought theyâd be.
i still plan on cleaning holes but its nice to know that when some people don't i won't probably die when i use their bolts
HowNOTtoHIGHLINE jup, well said
And that's why, you shouldn't... Something something dirty holes
Hi Ryan & Boby. IÂŽm a fan fo yours from germany and IÂŽd like to see you guys putting Petzl Batinox Bolts to the test.
IÂŽll gladly cover your expenses for one or two if you agree to aquire an destroy them (or your patio).
Let me know ;)
Happy to cover expense of a collinox to compare with a batinox if they test that
Vertikalo high send him an email, they should do it if you provide the funding. It's great to have this independent testing, so thank you if you do pay for some more.
Hit me up in email. Our standard for testing anything has been 6 bolts. 3 in sheer and 3 in tension. Really sucks to do that sometimes but it helps minimize the trolling that we aren't doing "science" because 1 bolt isn't enough for any conclusions. If you or a few people want to pay for that, we would be happy to break the most expensive glue in bolts in the world hahahaha. skylining@live.com
Thanks for another cool video. And very good point: the dirty holes are your second concern, first is **properly mixed epoxy**
I'm curious about the vertical vs horizontal holes. More dust will end up at the bottom in each case, which might result in different failure modes.
so the top of that hole would be clean based on the theory and have just as much adhesion as these?
Gravity kinda cleans out the topmost portion of the hole, so you get really good adhesion or the top 1.5 inches, that's why you see the concrete fail but only at the top. Effectively, you are only glueing in a 2" bolt regardless of the try length of your bolt. If you pulled a bolt glued in to spec, you should see that cone ish shaped failure starting at the approximately the tip of the bolt.
The glue pushes all the dust out so the dust is evenly distributed in the hole. I think rubbing the bolt a little "cleans" the sides of hole and mixes the dust inside of the epoxy which isn't so bad compared to the epoxy possibly only "sticking" to the dust. We plan on doing more tests.
@@HowNOT2 I'm not a rock climber and will never do the crazy awesome stuff you guys do, but love to watch your break tests and procedure videos. Keep up the good work!
Thatâs what it looked like to me, only adhesion on the top, so maybe the dust only got pushed up so far? Fine in concrete or granite, maybe less fine in rocks that are weaker per inch of depth of bolt?
And presumably horizontally drilled holes would also be very different with dust maybe more across whole length, and possibly less of it because the spiral is better at removing it without gravity.
Hi, I am would imagine that the dust of differents rock will act differently in the whole. There are rocks who are very gravely, that may not connect as in your test.
Theoretically I would think the more coarse the "dust" is, the more the glue should interact with the bolt and the rock and the stronger it should be. The super fine powder seems like it would be the weakest cause its just becoming a big glue/dust conglomerate material blob thing. But again that's totally just my theory.
@@EvanTheHamburgler I wonder if the epoxy might be less likely to wet super fine powders
@@Jefferson-ly5qe yea that's what I was thinking
I hope to some day ship you some of the home made bolts used in Brazil... And they are basically pressure hammered inside the granite and sometimes shimmed in
At work with glue in all thread we drill it, spin the drill to pull dust out with a vacuum and then glue them in. Now I donât feel bad about using a wire brush. Thanks.
I think that the porosity of the rock and the viscosity of the glue would Change how well the glue bonds to the rock. The higher porosity Rock types may grab the glue better mechanically, and thinner glue may saturate into porous and finer grain rock types. And the one that you were twisting possibly mixed the remaining dust in with the glue kind of like a rock filler. I use epoxy for many applications From climbing holds to gluing boats together. I'll be gluin titanium bolts in limestone on the next Caribbean's vacation, Good to know if I don't get every speck of dust it should be.. super good enough.
I just wanna put this out there.
Even the inside of a semi dirty concrete/drilled rock hole is always going to have better engagement with the rock than the bolt, unless it's a screw in bolt. Why? Surface area, and how the glue expands as it sets, in most of the hole even where, say, 1/3rd of the hole is packed with dirt grindings, the bolt (unless it's a finely threaded screw type) is going to have less surface area for the glue to grip, because it's smooth. Even a slightly damaged bolt is going to grip better because the damaged area creates more surface area than it being smoothed/undamaged. When you drill out concrete/rock it's not going to be really smooth inside the hole. There's more surface area on the concrete for the glue to grip than on the bolt. So, if you fill these holes complete, then insert the bolt, it might compromise the matrix in the glue slightly with the dust getting mixed into the glue, but the glue is NOT just sitting on top of these dust particulates, usually it's going to get mixed in with the matrix of the glue. TBH, I think to get the outcome shown by the other guy. You'd have to drill the hole, not clean it at all, insert the bolt and then try to inject the glue around the bolt. Instead of filling the hole with glue and pressing the bolt in. Understand what I'm saying?
The obvious exception would be drilling a half inch diameter hole, and putting a quarter inch diameter non threaded bolt.
All in all if you do at least 1/3rd of it logically, I think the bolt is going to hold beyond what would be needed for saftey of "SGE".
Not a climber, but a rigger for extremely heavy construction loads, with a formal science and engineering background.
This type of adhesive works by expanding as it cures inside the hole; placing the whole mechanical connection in tension.
On your first test with the threaded bolts what we are seeing is the concrete fail before the glue or the bolt. Those huge chunks of material being thrown off demonstrate how much bond there was between the adhesive and the concrete; they were basically the same or similar strength. Keep in mind concrete is porus, more so than most rock. This porosity may allow for a much stronger bond than you might find in a more dense rock like granite.
Loving the slow mo
Great jobđ
The glue wasn't sticking the walls at all, but happened to be taking up space, so that's what actually provided the strength. It's like a climbing nut, just the shape of the glue is wedged against the shape of the concrete. It could happen to solidify in a shape that doesn't provide any wedge action though, which I think would pull right out.
I wonder what exactly is going on. The parts that disengaged and pulled out had a very smooth finish. I suspect that when the hole is getting started it is harder to keep the drill steady and that that creates some mechanical features for the glue to jam in. Once it is going you get a very smooth hole and the dust allows the disengagement.
Also, the dust is going to fall to the bottom of the hole. It looks to me like the glue only engaged with the rock at the very tippy-top of the hole.
With a *super* smooth hole, talc like dust coating the walls, and somehow the epoxy not disturbing the talc, you'd probably get lower pullout. Mix the epoxy with the dust and you just get a sand/epoxy composite.
i couldnt find the english name, but there are "verbundanker" (compund anchors), a glass vial with resin, quarz grit, and aanister vial with a powdery hardener. normally used in concrete with a threaded rod ancher.
i'd be curious to see, how those compare. they're just 1-2 eurobucks a pop.
Drilling vertically will knock most of the dust that stays in down to the bottom. Where if you drilled horizontally the dust will sit along the "bottom" of the entire hole and not the back. This might create more of the issue you are trying for.
OK, Maybe not cleaning the dust should be reserved for horizontal climbs such as "The North face of the Uxbridge Road" where the bolts strength will be less affected
What i ment was there might be a higher concentration of dust at the bottom of a vertical hole, but less on the walls of the hole on the top half. Where as there will be more dust coverage, but to a lesser concentration in a horizontal hole. Which seems worse for glue.
i assure you my holes are dirty ;). dust stays on the sides of the hole just fine. if you did or horizontal placement the dust would stay just on the bottom and in theory not be on the top of the hole so it would stick to half the hole. That is the part about cleaning a hole that is a misconception, you don't need a lot of dust, a thin layer of dust in theory is just as dangerous. You can see the glue disengaged with the rock, it just surprised us how high it was.
I agree that both ways will have the top of the hole "clean" but in vertical the full force is spread around the entire bolt with a nice grab and no tearing action where with a horizontal the full force will be on only half the circumference of the bolt. The point on each side where the glue switches from good rock to dust will be a "sharp" point where the good glue will rip. This is the same issue with having under cutting with welds. Sharp angles on structural materials get a concentration of force and dont spread them out. This creates failure. You got 40-50 Kn and i wouldn't be surprised to see half that in a horizontal.
If the cement pad you poured was mixed by hand it will be less poures because a mixer adds air into the wet cement it helps the cement cure and be stronger as well as creating more tiny divots for the glue to hold on to (work in masonry so cement mortar and stone is my specialty
For about $10/yard you can have added to your mix at the concrete plant anti-crack fibers which add lots of strength to the concrete.
Great stuff as always! Thats amazing they still took 40+kN to pull out!
There is a good chance that granite is stronger in tension than concrete, so maybe you could get this effect in rock?
Also were you twisting/spinning the bolts in the holes? This dislodges dust from the sides of the hole and gives works the glue into the substrate, so if you simply insert the bolt and don't touch it then that could lead to a glue pull-out.
Would've been interesting to know if anything changes when those bolts were loaded to 10kn to all (or one other side) before. Great content btw!
Great point
@@jrmbayne I have to figure out what I meant by this. haha I don't understand my own comment. XD
A lot also depends on the MPA of concrete. On residential house it's around 25 MPA. On highrise I've seen 75 MPA. How strong is your concrete? Just curious? I've always cleaned the holes. Compressed air and a brush. In some situations; the builder has specified a primer on everything from glue in bolts to sikaflex construction adhesive sealant work. Interesting to see real life tests! The Ramset type cures extremely fast and in under 5 minutes you can torque it down. As per specification.
Cannot believe you are not getting more like! At the time i have wath there were 2000 view but only 220 like thats disapointing for a good video like that one
i guess people don't google dirty holes that often haha
would have been interessting to see a proper bolt with well cleaning in compare
Cool to see concrete fail like that. One "ballpark" number for concrete's tensile strength is 300 psi. 51kn is a bit over 11,000 lbf (or 11 kips in US building structural engineering), which at 300 psi would be 38 sq in, or about a 7 inch diameter circle. Not too far off from the patch that "coned out." So the "textbook" way we conceptualize/design for that type of failure in concrete actually lines up with reality!
Surely the fact that your fitting the bolts flat to the floor has an effect as all the duat will fall to the bottom of the hole but if your drilling in to a vartical wall the dust will sit along the whole length of the bolt ? The difference might be tiny but its something to consider maby ?
Can you do a real life tutorial on installation of all aforementioned bolts? And I mean, in rock, at a crag. Do's and do not's, why or why not's.
Iâd love to see a shear test on bolts without glue
i want to highline on glue ins without glue just to be funny
how many days did the concrete cure before test? and what was the PSI rating of the concrete?
so, threaded bolts beat twisted or wavy bolts.
and cleaning your holes is good practice. please do, but you have a good chance at survival if you dont.
Love your channel ! Great content every time.
I feel like you turned a glue-in bolt into an expansion bolt by letting the glue cure in dust.
there is a hilti-z glue in that is designed like that. glue turns into an expansion cone of sorts. made for rocks that seismic activity.
Would be really interesting to do an over-torque / under-torque tests (pullout & shear) on five piece bolts. 3/8 vs 1/2. SS vs PS.
Configuration Shear Pullout
3/8 SS under 50%
3/8 PS under 50%
3/8 SS over 50%
3/8 PS over 50%
3/8 SS over 100%
3/8 PS over 100%
...
Keep going up in torque until just before the install breaks the bolt.
uhhh should have watched the video first haha. Look forward to the video!
My thoughts are the following. The pictures look quite old and I think it's simply possible the glue used then wasn't as good yet. Then for a second I also imagine rock type would make a huge difference. Since then some of the dust might actually be lubricating
I mean it must matter on rock type as of vains going threw the rock could compromise it. Also drilling next the the edge of the concrete is asking for it to be weak
Could you have a go at doing Petzl clour bolts
Someone please correct me if I'm wrong but I think one of the main reasons that the glue separated from the concrete was due to the concrete failing. Atleast for the first two bolts, from this footage, the concrete breaks first and fails catastrophically, causing the concrete around the bolt to crack and fall away from the glue rather than the glue slipping. The 3rd test seems to behave more like expected if the glue was to slip against the concrete however I think it's still a similar thing happening.
The glue wouldn't have stuck to bolt like it did if it was only because concrete failed. I plan on redoing these tests in other rock.
Are DIRTY HOLES a MYTH ?!?!đđđ
This should just make you rest easier knowing your holes are clean. It should make you feel better about the bolt holes to.
These are all the circumstances that will cause a sloppy install to fail before a sling:
#1 âŠ..
Awesome stuff guys
Have you tried j-bweld?
Yes clean hole good hole.
I wonder how the kn would be after some years..
so what would happen if for some reason there was oil in the hole, maybee a guy tryed to lubricate the drill bit
You did a science!!
All anyone really needs to know about clearing holes for epoxy setting is that it was not done during the Big Dig in Boston and led to the death of a motorist via falling cement roof panel.
Clear ya holes. Clean holes.
How do these numbers compare to clean and clean-ish holes for strictly glue in (non-expansion)
bolts?
So do you think it would make any difference if you set the bolts horizontally in the concrete, then laid the slab down to do the test? Iâm just wondering if the dust will settle differently if youâre drilling and placing them in vertical vs horizontal dirty holes.
Where can you get the equipment to put in glue in bolts
its all in the bolting bible on slackline.com
Hey guys, I was wondering if you had ever tried break testing Samson amsteel blue dyneema fiber cord. The one I am looking at is 1/8 inch and was wondering what it would do with a single strand, a double strand, a three cord braid, and double three cord braid. I am looking at this academically from a stand point of an emergency high-rise rappeling system. It would only have to work once but could be retrieved and used again and could be stored in a small space while still allowing for several hundred feet of decent.
it has a low melting point so i don't know if it is good for rappelling. we have done a bunch of amsteel dyneema break tests. hit ctrl f on our slacksnap chart on our website to see all of them slackline.com
I think my biggest issue here is that concrete is not solid rock. For one, the failure mode is different. The rock almost certainly isn't going to give out structurally before the bolt pulls out. But more importantly, concrete is constructed of very fine rock particles which makes it far more rough of a surface. I could easily imagine that this makes the glue bond much easier with the edges of the hole, whereas the inside of a hole in rock is likely to be very smooth and much more likely to pull out. Just a theory, but I would greatly appreciate a test with real rock!
Tests starting at 8:06 are in granite.
Oh interesting. Nice!
Some solid rock isn't really solid rock either. Sandstones and various other sedimentary rocks are also a cemented aggregate with a very fine structure (and are typically considerably weaker than concrete). Granite is a pretty different material, as are metamorphic rocks, and they would fail somewhat differently.
not all rocks are as hard as you might think. my backyard is full of rock that spalled like this concrete. I even had granite in the sierras that i tested completely cone on me. I have had extremely great adhesion on granite tests too. Check out our boltbuster chart on website, we have only published a few of all that we have done. slackline.com
Epoxy bolts
Oh man I have a dirty mind I love all your wordsđ
Cheers.
More powder just helps bond the bolt to epoxy to the concrete,epoxy acts as a fluid an Mixes all together
44 kn an 55 kn come on that hold ur house
How long have the concrete hardened?
I'd like to meet this Jim you speak of....
Freshly poured concrete canât compare to natural rock, so Iâd imagine the tests will be compromised.
You also tested with a vertical hole so all the dust would go to the bottom of the hole and itâs unlikely it would affect strength but a horizontal hole would cause the dust to sit along the whole length of the hole which could reduce strength
WOW!!!
Just for perspective, do you know what properly brushed bolts in this concrete fail at?
almost the same hahahaha. check out boltbuster chart on slackline.com
awesome video man! thank you, by the way what is the end song name?
i don't know. i hired someone fancy to make that for me haha
I love dirty holes!
Are there tests in threaded rod glued-in, with nut-washer and hanger?
yes, in sandstone. hit ctrl F on boltbuster chart. on slackline.com
HowNOTtoHIGHLINE Thanks a lot bronx!
So nice to see all the job youâre doing
Do you have any idea how much your drop tower is going to cost? We'll need to do a gofundme or something :)
Yup. Picking out dynos and blueprinting it and figuring out at least 50 experiments. Then after I have something to present to everyone then I will do a go fund me. It will be a really cool project!
Its good to stay away from dirty holes, it's bad for your health
2:01
âSuper coned outâ
Is this a good or a bad sign?
Pulling out a cone of concrete means the glue has some adhesion to the wall of the hole
It shows how the force is being applied on the concrete. Super interesting is what it is!
Epoxy is a broad term covering a range of adhesives. The epoxy that works best for wood is not the epoxy that works best for metals. I have not specific knowledge about epoxy and various materials, but I believe there is no reason to think that the epoxy that works in concrete will work equally well in granite (or limestone or sandstone or shale or . . . .) Since actually climbing/highlining bolts are placed in naturally occurring rock, your experiments in concrete may have little bearing on what happens out in the wild.
I have done hundreds of epoxy glue in tests in rocks. It works just fine :)
Have you ever tried to pull thunderbolts to see the strength of them?
send link to thunderbolts? i haven't seen them
Were his bolts old or newly installed? I would imagine bolts that had been wiggled a bit from use over the course of a few months or longer, would slide out the hole a lot easier...
Kind of a pointless test, as climbing bolts are placed in rock and this is sub en959. Also the bolts are placed far too close to each other. Plus you didn't allow for the different types of epoxy glues out there.
Your test are very hole-y. I mean dirt-y. I mean they need a shower. I mean looking good.
You all should see how well flex glue holds in bolts lolol
Is it just me, or did anybody else feel sorry for that ant that crawled up to the bolt at 1:33 just before it blasted out of the concrete?
Nobody is on tiktok
Looks like maybe the concrete wasn't properly cured?