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Keeping the crucible insulated

Yo! What’s up guys. I’m finally gonna start learning to sand cast so I could try gypsy setting some thicker pieces. Since I work out of an apartment, casting wasn’t much of an option. Now I should be able to cast at my grandparents house, but previously whenever I would try and melt metal down the most I could get with a mapp gas ts8000 torch was around 30 grams.

I don’t believe this is enough for thicker sand casts, and was wondering if y’all have pictures/suggestions for created some sort of firebrick insulation chamber for your crucibles before you cast. Like, do I need to get a specific temp firebrick? hard or soft :smirk:?

I also wanted to mention that I have an acetylene oxygen B tank system, but it’s a little torch and haven’t gotten good results with the rose bud tip.

Hope to see some of ur set ups! Thanks for reading.

30 grams? Even in gold, thats a fair amount of metal. With silver, being less dense, its even more. For many years the shop I worked in routinely cast one or two rings/pieces at a time, carefully using enough metal to fill the sprue, but not much more. Needing 30 grams, almost a troy ounce, was pretty unusual. The majority of rings, even with the sprue, do not need that much. Now, if you are making your patterns to be much more massive than usual jewelry pieces, all bets are off. But its simple to take your model and a suitable bit of similar material to mimic the needed sprue, and weigh it. A bit of juggling with the respective specific gravities (density) of your model and the metal you are casting will tell you exactly how much metal you need… (weight of your model, divided by its S.G., and that number multiplied by the S.G. of the metal you are casting in, gives you the weight of the casting.)

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