Forum / Welding, Forge & Casting
✅ First aluminum melt: crucible made from a steel pipe cap. How long will it last?
@thrift_queen_mo
Oct 14, 2026 · 404 views
Welded a cap onto 4 inch pipe for a crucible, did two melts of cans. Works, but the inside is getting flaky. Is this a problem?
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2 replies
✅ Accepted solution
It is dissolving into your aluminum. Steel crucibles work for a handful of melts, then they get thin and your castings pick up iron (brittle, hard to machine). A clay-graphite A4 is about $35 and lasts years if you preheat it and never set it on cold concrete. Also: stop melting cans. Mostly oxide and paint; use cast scrap, heat sinks, old pistons.
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And check the weld on that cap every melt. A crucible failing mid-pour is the scariest thing in this hobby.
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