casting .03125" script words in graphite with aluminum
I made a graphite mold with 1/32" em slots but getting the metal into the pockets has turned out problematic. I'm considering milling a cover plate with journals to transmit the aluminum to one end of a word while venting at the other end. The pockets are script words, so there will be multiple paths for the metal to follow.
How much height of pressure from my crucible would be enough to force the aluminum through to the vents or should I consider some other form of pressure?
At present, am considering a stainless enclosure that reroutes the flame from around the sides of the graphite plate, back inward above it to a center graphite "drilled" crucible mounted to the top plate.
I'm using discarded EDM graphite and I have one that's about 8 inches long that I could drill out for a crucible but if that's not enough height for this situation, it'd be a lot of time wasted.
Any thoughts or alternate ideas?
Re: casting .03125" script words in graphite with aluminum
I actually used 3 graphite plates, ~.150" thick each. Bottom plate with letter pockets sits directly over flame. Second plate has v cut-thru slots that I put cut lengths of .070 aluminum wire into for melting. Top plate was for physical pressure against wire to aid melting, as well as a cover to keep oxygen from causing too much slag and mold oxidation. Bottom plate got cherry red. Second plate somewhat less. Top was red only in center. The proposed stainless shield re-route of heat would improve the upper plates heat I think. My propane tank was nearly empty so I didn't get a very long burn.