Foundry 37: Foam Plug with Pyroceram Glass
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- čas přidán 18. 05. 2019
- This test is similar to Foundry 31 but with a foam plug (Video says Foundry 32 but that video has an inside curve between sprue and runner.
Sprue fills well with the foam plug but runner has a delay in filling similar to Foundry 31. - Auta a dopravní prostředky
I keep learning from your work! For my next casting, I'm going to incorporate what I have learned. I think I am also going to begin using a 3 part mold: a shallow foot (lower drag), a drag (middle drag), and a cope. The shallow foot will only be used to incorporate the runner below the pattern in the drag. That will allow me to feed the mold by the contra-gravity method. It's an idea I have been considering, and I think it can become a routine amendment to the typical cope and drag casting method.
I don't have video capabilities, but I will take still pictures of the process the next time I cast something.
Thanks, Andy!
You're ahead of me. I'm still just wanting to feed horizontally at the bottom of the mold.
One of the things I have learned is how fast speed builds up with depth. I really don't want to pour a mm deeper than I have to so I'm looking at how a ramp to the low section of the pattern will work. Of course on the other hand, if you kill the velocity into t spin trap you can have a slow feed into the mold.
You really need to get you a cell phone to make videos (and they can be used for phone calls).
@@andrewmartin4258 I'm really not talking any more depth than you have in your glass faced molds. Imagine splitting the bottom of the drag off just at the top of the runner. The only thing that would be in the bottom drag would be the imprint of the runner. The opening for the gate would be in the middle drag, and sit right on top of the of the runner when the flask was assembled.
I have a dumb phone, but I don't want anything smarter -- too easy for it to become a leash that other people can use to tug on you with. I do have a little camera, and might try to make some video with it, but it's not a dedicated video camera. I'll think about it. I have done video editing before, and I know what a chore it is, so I do appreciate the planning, time, and skill that go into your work.
Your accent is southern. Northern Georgia? South central Tennessee?
@@carlericvonkleistiii2188 Seems like a good plan. I think it's actually called a cheek.
Cobb County, but I don't live in Smyrna. Where the heck is that anyway? Close to Marietta? (Pronounced Murr-edda)
@@andrewmartin4258 A cheek. I figured someone already had a name for it, but in my limited experience hadn't seen one in use or heard what it was called.
Cobb County -- well, I was close with my guess. I grew up mostly in central SC, but spent a lot of time in western NC as a child. Just moved back to Greenville, SC from western VA (not WV.)
@@andrewmartin4258 , You're quite correct. The bottom most part of a flask is the drag, the top is the cope. Anything between the two (no matter how many there are) is called a Cheek. In several videos I have made I made use of the cheek when making the mold. I invite you to watch my videos.
I was particularly interested in the melting rate of the foam plug and how the metal pushed the smoke out of the mold cavity almost immediately. I intend to try using foam plugs at the base of the sprue so that the pouring basin and sprue will fill and pressurize the gating system. That way turbulence will be eliminated before the metal will reach the ingates. Nice exhibition video.
Thanks for your kind comments!
This sprue is designed to be tapered to keep the metal front intact. I think it does that but it is difficult to see. What the foam plug at the top does is ensure you have established a liquid level before flow begins down the sprue to avoid ingesting air and it does that that very well. While pouring you can see continuous fluid level.
I like that the smoke first of all is made by consuming oxygen, then flushes the air ahead of it. That was an unexpected bonus of the foam.
I know this cost you a chuck of money for the glass, it is a great demonstration! It just seems safer to not have the glass explode. Your work should be shown in college courses. Great, great job.
Once the money is spent, you hardly miss it. I still have one piece of Pyroceram. My plan is to try to pull it off while the metal is still liquid.
Hmmm, not sure which college courses would want a non-technical discussion of what happens in a flask.
I have grand plans to summarize what I've been doing in the hope that it will be a cookbook sort of on how to minimize oxide film damage to home castings.
Thanks for the nice comment.
Looking forward to your cook book. As I get closer to retirement I want to spend lots of time doing metal casting, machining, and reinventing old processes. You are doing what I would love to do.
@@acrussell1959 Glad to hear you have a retirement goal. I'm new to metal casting but love it. And it is nice to be retired, have good health, and be able to pursue your passion.
@@andrewmartin4258 Wish I was retired. I'll turn 60 in August...still have ways to go.
@@andrewmartin4258 , after the skin of the casting has formed I hope. People who make busts that are hollow on the inside usually wait 3 seconds for the skin to form before they pour the liquid metal back into the crucible. Saves metal that way.
Thank you! This was worth a thousand words!
Thanks for your kind words!
Always interesting when your new posts are up. 👍
What happens if the mold part is below the sprue? How would it fill?
Thank you!
If the mold is below the sprue, or if yo pour directly into the mold you will retain all the oxides going down the sprue in the mold. This is the primary cause of defects such as porosity and hot tears. You can get a superficially complete casting pouring in directly but it will have internal defects. When the metal hits the bottom it will splash, breaking the oxide film and creating more during the splashing and turbulence.
This entire series of videos is aimed at minimizing bifilm creation during pouring by minimizing turbulence, providing a bypass runner to take the lead oxides, and filling the mold cavity below 20 inches per second velocity in the gate into the mold.
Thanks for commenting.
Did you design these ways or had they been used by foundries historically? Good quality fill.
Thanks for your kind comments!
I've been trying to learn and improve my castings. Using the glass flask with video has helped me see where what I'm doing can be improved. This was basically to compare a curved sprue with what people normally do. The curved sprue avoids mixing with air and the foam plug pushes a non-oxygen contained slug of vapor in front of the metal front. Liquid aluminum is very susceptible to oxygen.
Very instructive video, thank you. But please, what is the "plug" that holds the metal (mark 1) 1/22... right at the beginning of the pour? Thank you
Styrofoam. In my case it is the pink foam board I use for lost foam casting as well.
Not only does it allow a short pause before metal begins flowing down the sprue to insure there is a stable liquid level in the pouring cup, it flushes air from the mold with the vaporized foam. It think the foam also reacts with oxygen when it is hot thereby also reducing the potential for aluminum contact with oxygen.
Thanks for commenting.
@@andrewmartin4258 Many thanks. I do a little foundry work for fun... And it takes a long time to learn. But this is the 1st time I've understood that casting has to be slow, regular. No air pockets. And the little "plug/styrofoam" allows preliminary filling of the casting cavity, absorbing oxygen as it burns. It's fabulous, magical! And nature adds a skin around the liquid, a skin that you have to learn not to tear. No book explains this! It's one of my best foundry lessons! (note: I practice steam modelling, so I rather cast brass, bronze (from salvage)MERCI CHER MONSIEUR!
@@cccbbb3161 Slow and uniform (regular) but as fast as is practical to maintain control. 😂
Steam modeling is very cool!
I doubt there's as much value with using foam in brass or bronze casting but there might be some.
Merci, mon ami
I love your videos with the cut away "ant farm" views. I learn a lot about how the metal moves and what works well. I would like to ask though, could you do a pour where everything is wrong? Show us what a bad pour looks like, and the consequences of a bad pour. Point out what each problem looks like on a cast part so we can better identify our problems after a bad pour, so we can better address our specific issues.
Interesting request. I'll think on that one.
you can get a small improvement @1:38 by a purpose-built curve in runner bar base. helps the ingate even more!
Thanks for the comment.
Nice to see the pyroceram worked out on the side of not breaking. A bit disappointing that the aluminum adheres to the surface. I wonder if there is a coating which could be applied to prevent the surface damage to the pyroceram and wouldn't impair the transparency too much?
A coating would be an interesting idea. Kiln wash would probably be too obscuring.
water glass perhaps? good for 2,000 F
@@currenciacurrencia1860 sodium silicate as a surface coating... maybe.
The question is, what coatings will adhere to the surface of the Pyroceram, will not obscure the visuals too much, will be successful in protecting the Pyroceram from molten aluminum at pouring temperatures and will not significantly change the pouring characteristics by reducing or increasing the metal wetting to the surface?
@@currenciacurrencia1860 That's worth a try, if I can get it on smooth enough. Thanks!
One can dilute or thicken water glass to any viscosity you prefer. You can pour it, brush it, spray it, or mix it with silica sand or alumina oxide.
In using it for binder in sand, it eliminates the need to be using 10% clay. Clay expands at 1,000 F (500 C) and this causes surface finish troubles in the pour of aluminium just when you do not need that happening.
Disculpe maestro una pregunta como se llama ese sistema de vaciado por piscina de rebozo
I regret the translation of your comment is not easy for me to understand.
The pouring basin is the design shared by Olfoundryman. Martin (his first name, no relation to me) really knows his stuff and has helped me tremendously. You can rely on anything and everything he says.
@@andrewmartin4258 Excuse me, teacher, but I wanted to know what that emptying system is called, the rebozo pool.
@@heilerdelarosa It is a pouring basin with a foam plug.
It's interest to see the aluminum solidify, but somehow, without the glass explosion it feels very anticlimactic.
I guess that says a lot about my mental condition 🤔.
The explosion always makes me jump, but I missed it too.
Good progress. I would have liked to seen a closeup at 3:54. Maybe next time ;-)
Lean closer to your screen, please.
I plan to polish it and give it a good inspection. Just didn't do it for this video.
You could do this with zinc instead, the glass might hold up better
Yes, zinc would not damage the glass. It would make a col video, but I was interested in aluminum. The density of zinc is much greater than aluminum. I have no idea how it compares on viscosity at pouring temperature.
Thanks for commenting.
Got sent here by swdweeb. Glad to have been aimed here .Will be spending some time perusing your videos! Good watching.
Thanks for commenting. Anything you can add is appreciated.