first serious testing of my homemade crucibles. 60:40 grog to fireclay.
1 - dry mix, split whilst demoulding, the bottom (now very small crucible) melted iron twice. no drying and no firing
2- dry mix, worked better and has been thoroughly dried but still a small defect at the top when demoulding. not used yet
3-best yet, dry mix, good ramming, thorough drying. not used yet
4-wetter mix, easier ramming but poor result. this became the cupola crucible and worked as a crucible in the induction heater but the cupola aspect failed due to the plug refusing to be removed. i managed to remove some of the contents with a flat bar but its probably junk now.
5-dry mix, shorter and thinner, rapid induction drying and fired for about 15 minutes in propane forge. charged with AL and ingot poured. the inside held up well with the cold AL being very easy to completly remove. a fissure at the base appeared during the induction drying.
for the diy melter crucibles are definitely a thing and being able to form and fire refractory structures with only two ingredients neither of which have a shelf life is a road worth exploring. i mixed 4 kgs of grog and clay and have made 5 crucibles. 50kgs of mix costs about £50. thats about £1/crucible and less as the walls get thinner. the last 2 i bought for the induction melter cost more than the fifty or so i can make from the bags of grog and clay.
