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Custom Designed Jewelry / Silversmithing / Metalsmithing /Soldering Saftey  / Re:
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on: February 23, 2016, 08:43:54 pm
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Oh yeah, that's a veneer screw I used on the vulcanizer. It's just bolted down on another plate centered on the top plate. I used 12ga wire and grounded the dials to the box. Be sure to be safe when building anything like this. There are potential electrical, fire and pressure explosion hazards involved in making these things. Always wear safety goggles when drilling into metal.
Oh and don't use a glass bowl. You need something with the consistency of plexiglass.
Sent from my SM-G900P using Tapatalk
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Custom Designed Jewelry / Silversmithing / Metalsmithing /Soldering Saftey / DiY Foundry Update
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on: February 23, 2016, 08:35:30 pm
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Soooo I know It's been a while, but here's my updated gear I put together. I made a gas extractor for degassing investment plaster. I used a plastic bowl, a neoprene rubber gasket, a 1/8" thick galvanized steel plate, an old bathroom cabinet for a base, a vacuum pump, and regular brass fittings for the pump to connect to. I also made a vulcanizer using hardwood, red silicone as an insulator, steel plates, light dimmers as dials and stove top heating elements as the heating coils. I put springs in between the bolts and the plates holding the elements to account for thermal expansion of the metals. Also, I made a wax injector out of an old aluminum container, a self-heating cooker, a steel plate, some threaded rods, and NPT brass fittings. I custom made the nozzle out of a 1/4" NPT brass coupler that connects to the ball valve on one end and is soldered to a plasma cutting tip on the other side, that is drilled to the standard hole size of a sprew former. I'm rebuilding a kiln right now and finishing up welding together my vacuum caster. I'll post updates soon. Feel free to ask me any questions. Everything works and is totally cost effective. Don't spend thousands on gear, when you can make it yourself.          |
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Custom Designed Jewelry / Silversmithing / Metalsmithing /Soldering Saftey / Re: Building a vacuum assisted caster for silver and gold.
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on: January 20, 2016, 11:50:40 pm
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I'm having trouble finding a machined aluminum box for this vacuum chamber to fit around the flanged/perforated flask. I read somewhere about people converting pressure cookers into vacuum chambers, so I'm wondering if I can take an old pressure cooker and install a vacuum gauge and a line in for my vacuum pump.
I'll be hitting a few shops tomorrow to see what I can find that's large enough for this and still cost effective. I'm going to be using a 3" diameter flask with the flanged edge. Anyone know a good place to find one for cheap?
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Custom Designed Jewelry / Silversmithing / Metalsmithing /Soldering Saftey / Re: Building a vacuum assisted caster for silver and gold.
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on: January 20, 2016, 11:44:29 pm
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In hopes that this will save some of you having a vacuum casting failure I will share a piece of information that I didn't know about until a smarta$$ told me after I had problems.
In centrifigal casting, the spueing is done like a tree, with the feeder sprues coming off in an angle like a "Y" where the base of the Y is where the button would be.
When sprueing your wax for vacuum casting when you are placing the flask in a cavity, the feeder sprues should be horizontal, like a "T" to the main feeder sprue. This is because the vacuum does not exert the same amount of force ramming the metal into the investment and the metal has a chance to freeze before it can reach the bottom and go out to the sides.
Also, all vacuum cast flasks should have a minimum of 1' investment on the top. If you blow out the investment in a centrifigal caster, the metal generally will hit the back of the cradle and stop there. But with a vacuum caster, you can actually pull it into the caster. The man who "loaned" me his caster made this mistake and there's about 3-4 ounces of silver in the inside of the caster that's welded to the steel. If you sucked this into plastic tubing you could have a potential hazardous situation.
I know that your vacuum caster will work just fine and am looking forward to seeing pictures from all of you how you've made your own machines. But I would recommend that you give a thought to what would happen with the molten metal if you do have a blowout and where it is likely to go. The same thing can and should be said about centrifigal casters, which is why I bought a NeyCraft. The NeyCraft caster has a barrel that moves around with the crucible so if a blowout happens, the metal hits one spot on the barrel instead of being flung all the way around and bouncing around and out. And with casting, it seems, whatever can happen, does.
Debbie K
This is some very important information here, Debbie. Thanks a bunch. This could save us all some serious trouble here. |
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Custom Designed Jewelry / Silversmithing / Metalsmithing /Soldering Saftey / Re: Building a vacuum assisted caster for silver and gold.
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on: January 20, 2016, 11:40:21 pm
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Built a vacuum table 4 yrs ago. Purschased a used HVAC air conditioner service vacuum, you can find them on Craigs list quite often. used a sheet of 1/4" aluminum for the table, drilled and tapped a hole in the center and use a sheet of red hi temp silicone gasket material for the seal. there is an additional tapped hole with a valve off to the side to be used with a plexi bell jar that I use for debubblizing investment.
In use the standard flask is filled short of the rim by 3/8 to 1/2" with a series of short holes drilled around the outside edge of the flask for additional surface area for the vacuum to draw on. do not dill more the a inch deep and watch out for the location of your wax pattern. when the flask has calcined it is placed on the gasket, the pump is started and as soon as it draws a vacuum the molten metal is poured in.
I have pictures of the table and will see if I can find them for posting.
That sounds very interesting. I would certainly love to take a look at some pictures to get a better idea of what you created here. Thanks for your input on the subject! |
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Custom Designed Jewelry / Silversmithing / Metalsmithing /Soldering Saftey / Re: Building a vacuum assisted caster for silver and gold.
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on: January 19, 2016, 10:18:53 pm
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Thank you guys for all your input on this subject. Hopefully I can get this little project to work so I can share helpful information with anyone that's interested.
Debby, I'm using a vacuum cavity to fit the perforated flasks used for vacuum casting. This allows for the vacuum to pull on the investment from all sides, allowing the flow of the molten metal to fill every little recess in the mould perfectly. I've been doing a lot of research on the subject, and it appears that when you use a vacuum caster that only pulls on the flask from the base, that it doesn't fill the horizontal cavities in the plaster very well.
I've been reading that centrifugal casting has a higher initial fill temperature, which helps it all solidify more homogeneously, but that vacuum assisted casting fills the moulds more precisely than any other form of casting when using the perforated flasks.
I found some of these silicon gaskets for real cheap on eBay. They have a notably lower max temperature than the casting temperature for the both silver and gold, so like Debby said, they will deteriorate with use. Apparently they also make graphite gaskets to use in combination with the red silicon gaskets and this really extends the life of the silicon since graphite is such a poor thermal conductor.
I'll be ordering parts today and tomorrow and hitting the Home Depo for some extra fittings and such and I'll share my progress with you guys as I go along. Again, thanks for all your input, guys.
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Custom Designed Jewelry / Silversmithing / Metalsmithing /Soldering Saftey / Re: Building a vacuum assisted caster for silver and gold.
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on: January 19, 2016, 02:31:22 pm
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Thanks, Shawn. I'll actually be sharing all my successful DIY plans for creating both a vacuum castor, a investment vacuum chamber, a propane/ compressed air torch and a vulcanizer with everybody here once I am done creating my little foundry. Hopefully it'll help somebody else find out how to make all of this for cheap, since these big corporations have been getting the best of us all charging hundreds of dollars for parts that require nowhere near that much to assemble.
DIY all day.
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Custom Designed Jewelry / Silversmithing / Metalsmithing /Soldering Saftey / Building a vacuum assisted caster for silver and gold.
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on: January 19, 2016, 01:20:24 pm
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Okay guys, so this topic might be stretching the boundaries of this specific part of the forum a little bit, but I was hoping somebody here might have a little knowledge about this and this seemed to be the best place to ask this question on this forum.
I am building a vacuum casting machine out of a vacuum pump, silicon hoses and some metal canisters that are air tight and cut to fit the perforated vacuum flasks normally used with the actual retail machines.
In order to assure that the seals do not melt away when the hot flask is placed into it, I need a little information on where I can find the right type of seals for this so that the pump can create a vacuum inside the canister and pull the metal down into the mould.
Any ideas are welcome, thank you.
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Lapidary Shop / Moderator, Catmandewe ( Tony ) / Miscellaneous Shop Talk / Re: Polishing a crack
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on: November 29, 2015, 03:42:27 pm
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I've had this same issue. So you guys recommend epoxy to fill the cracks after cleaning them out? I had this issue with Labradorite, and the cracks only became visible after cerium oxide was used. I had used diamond grit from 80-14,000 to do the prepolishing and first polishing stage. I heard sonic jewelry cleaners could work out for this, but I've yet to try it.
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