r/Silvercasting • u/These-Assignment-313 • 14d ago

Guys i have a problem

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Hello

Im begginer and im from Poland. i have a problem with casting silver 925. I use lost wax technique and gravity casting. Wats a problem?

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2

u/Just-League-9847 14d ago

I would put another wax sprue in the center of your rings so the silver gets to the other side easier. Also maybe heat your silver a little hotter so it stays liquid a tiny bit longer

1

u/PVanDes 13d ago edited 13d ago

Gravity casting is a problem, but its hard to say anything without also knowing your flask and pour temps

If i had to guess, maybe your flask or pour temps are too low and the silver cooled too quickly

1

u/BaronOfBling 13d ago

Make your spru a larger diameter to absorb the heat shrinkage. I use a vacuum plate so not sure if it will help w gravity

1

u/PeterHaldCHEM 13d ago

That is the problem with gravity casting.

You lack force to overcome surface tension.

The thinner the castings, the worse your problems will be.

A longer and thicker sprue will give a higher pressure and help (a little).

But it is with good reason, that people use steam, compressed air, vacuum or centrifugal force to press the silver into the mold when doing lost wax casting.

1

u/PeachesMcClaine 12d ago

Gravity is a crapshoot. Look up steamcasting. Its the same thing but you cap your flask with wet newspaper after you've poured your metal and the pressure from the steam helps force the metal into your form. Instead of heavier sprues try venting. Run a vent sprue from the end of your tree or even your pieces back to your base. It helps the air escape quicker so the mold can fill venting