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Hello,
I made some lost wax castings in the flasks using pure copper. In all castings there were large voids and holes, it happened to me sometimes even with silver, but to a lesser extent, with copper instead the final result is completely unusable, I've never been able to figure out what caused it and how to fix it the problem. Does anyone know how I could fix it? Thanks a lot.
Hi MDK, and welcome to the forum.
First you need to tell us what casting method, and torch you are using. Then a member with the knowledge will reply. Dennis.
I heated the flask in which the wax model was contained, inside an oven following a burn out cycle. When it got to temperature I took it out of the oven and placed it on a shelf. I immediately poured molten copper into it. I didn't use a torch for melting, I used an electric furnace with a graphite crucible.Quote:
Originally Posted by Dennis
I put the flask in which the wax model was contained, inside an oven following a burn out cycle. When it got to temperature I took it out of the oven and placed it on a shelf. I immediately poured molten copper into it. I didn't use a torch for melting, I used an electric furnace with a graphite crucible.Quote:
Originally Posted by Dennis
I am not an expert, but unless you are using a vast ecccess of metal, and huge sprues, you will have no success using the force of gravity alone.
You need a casting machine.
Alternatively try the Delft Clay method, which is a form of sand casting, or use cuttlefish.
Have patience and more members will join in. Dennis.
Check out this article about porosity in copper … https://www.totalmateria.com/Article64.htm I think your problem is to do with gassing of pure copper. A floating flux might help like borax. However I don’t think a graphite crucible can handle borax. A gas torch might work better by create a shield and maybe reducing its purity might work by adding silver or tin … I’ve had some successes with copper using small handheld ceramic crucibles and an Oxy propane torch and using powdered borax. Last time I melted some copper, I filmed it and made a video … this is a link to the short, edited down version … https://youtube.com/shorts/xsxq6BJOY9g … N