Metal Casting Zone

Yes, if you get a small tank to build vacuum in then a ball valve to release it all at once. All you would need is a table like the one you have built and some metal tubes to pour your investment molds in. I've seen a video on You toob, I liked it because they didn't build a chamber to put the mold in. Just set it on a hole and pulled the vacuum down through it. I've got some of the red silicone rubber but I'm not sure of the temp rating on it. I think it's 1700F I need to contact the company. I've been trying to get some 3 and 4 inch conduit from the electricians at work, no luck yet.

I do love engineering on the cheep. And do enjoy your images. Oddly the gizmos that do not go beyond pen and ink are sometimes much more instructive and helpful in general in the long run.

I have to say I think Jammer was dead wrong on this one:

"Just be careful, if it did break it would send glass flying in all directions."

Not glass, nope he's wrong, just really fast moving shards.

Mind you I was the fool often seen walking out on 10 foot planks over entryways on 3O inches of aluminum walking stilts throwing up insulation and swinging a stapler as fast as I could. That and many other such misadventures. Not stupid, just invincible. I recon I was about 22 then. Now if I stand up too fast the world starts spinning and I might end up falling back into my seat or kissing the carpet.

You have proof of concept there for $13. Now throw more thought at it before more action, and ponder what 200% more investment could yield you. Just how very much better can you make it with another 25 bucks. Safer and more accurate and repeatable results, limiting reworks. Might want to dismiss the safety aspects, you've got two eyes. 75% chance you wouldn't even be facing it when the shards went flying.

Blobber

I hear you about safety. Worth it... but I don't understand what 200% more investment is all about. What are you talking about? And what's another $25 for? Got anything specific in mind?

As a de-bubbler, this is more than concept, I tried it, it works! As a vacuum caster, yes, just a concept - although, as a side note, I tried STEAM casting last night for the first time and it worked! Amazing and cheaper than ANY other option. I found all the additional supplies I needed laying around (one dowel, one jar lid)!

I made the wax very hastily, not expecting this to work, but it did. 1.5 hours, start to finish. Includes wax modeling, investing, burnout, casting and polish!

Your little kiln must be working well. Steam casting is interesting, looks like a good way to get burnt. Oh well, I've been burned before.

Here's one video of a vacuum table. This guy has all the expensive toys. Looks like it would be easy to build.

Yeah, my hand did get a little HOT. Gloves next time.

Looks like the secret to vacuum casting is that silicon rubber pad, and making sure your flask is sitting on that nice and tight. Seems like a little clamp might help ensure a good seal.

Steam, sling, gravity via a heavy button; with all the ways to get a job done its sometimes hard to choose one.

Dave I didn't see you had updated an earlier post to mention you put up a Lexan shield between you and your glass vacuum chamber. Glad of that.

I think I sound like an old ninny sometimes hammering safety so much. I'm just very aware of the shy folks that don't post but read our post, (they are many, we are few,) and the folks years from the present that search the forums and might follow our example, and even give weight to my comments even if that is to cheer something on that I actually feel is a bad idea.

OK enough of that.

Sorry I wasn't clear. By "doubling investment" I was talking about doubling dollar cost. Not investment powder.

Dave the 200% or $26 were rough figures for doubling or tripling your small investment of $13. $26-39 likely is affordable, although it has been a while since I looked in your wallet.

The device might work as is but I would call it more "proof of effect" and not "proof of concept," as it is unsafe in that configuration. Jammer's chamber is likely polycarbonate plastic and may break into several pieces,but glass will explode after the implosion sending many different sized transparent shards that would be very difficult to dig out of human tissue especially the white of worst case cornea of the eye.

So how would I throw more coin at it? First of course a better chamber. Perhaps a simple heavy pipe coupling and an inch of flat Plexiglas on top of that, even two layers of 1/2" glued together. Rubber gasket can go above and below. A regulator valve so I actually know what amount of vacuum I am using and can inssure what has worked very well can be reproduced. By adjustment for differing needs such as investment vs silicone vs a different brand and viscosity of silicone, etc. And a safety valve to release anything over the maximum vacuum I will ever need. The box you are using has unused top area, so a larger chamber is possible if larger gasket was accuired, And since there is no obstruction even a larger table could be placed on top of that. So Safety first, effectiveness second, and maximizing utility third.

I am not familiar with the fundamentals of refrigerator compressors. Seems I remember the freon was mentioned as the primary lubricant for the bearings as well as its other benefits.

I like the thick-plexi-over-a-pipe solution for safe "bell jar" and a vacuum gauge is probably also a great idea. In those two ways alone, another $30 could certainly afford some improvements to the system. Great ideas.

I've never heard of the refrigerant acting as a lubricant in the compressor system. Then again I haven't ever really heard much about what goes on underneath a refrigerator. Worth looking into.

I believe blobber is right. You may freeze up you compressor if you run it very long with out oil. Check with an appliance repairman and ask him what the best type of oil you could drop in before you start it up. I think a couple drops of a light machine oil would work. run the exhaust into a can with some coffee filters or cloth to minimize the oil vapor in the room.
Check with local scuba shops for tanks that failed hydro, or with the place that tests them. One of the big aluminum ones would be good, just cut it off and put something flat in the bottom for a table and cover with lexan/polycarbanate. The shop I used to go to was in Ballard on Shilshole Ave. or check with Divers Institute of Technology, My Alma Mater. But, that was back in the 80's. They are still there, just moved north of the Ballard bridge on the canal. Get a bowl of chili at Mike's for me if you go.