Hello all,

Last night my friend and I built a functional aluminum forge, however the only weak point was the crucible. We used a ceramic mug that held up reasonably well (20min@1300°F+) but eventually cracked from the heat. In an effort to build a stronger crucible, I was thinking of using cement. A cylinder with walls 3/4" thick, a 2 3/4" hole in the center to hold the materials to be melted, and a 1" floor to withstand the higher temperatures from the bottom, and a cap with a 1" plug to fit into the crucible pot.

Would you expect the cement to hold up to the high temperatures (Maybe 2000°F) for a longer amount of time? I tried to do research online, and found out that cement wont crumble until ~ 2000°C, but I'm sure that was brand specific and things such as mixing methods could affect the strength of the concrete. Any suggestions there would be helpful too.

Obviously more experimentation is in order, but any information anyone might have would help tremendously.

In my musings on the subject I always imagined I'd use a short piece of steel pipe with an endcap, then cleaned and polished. If you had access to a welder you could add eyelets too.

http://i36.tinypic.com/sdmhx3.jpg
From DIY.

Check out this thread:
http://www.totse.com/community/showthread.php?t=2161194

Check out this site:
http://backyardmetalcasting.com/ccfurnace01.html

Just a steel pipe with a disk welded onto one end should last for a few runs.

Steel will work just fine, peferably something about 1/4" thick. It'll take longer for it to heat up and melt your aluminum, but it would be safer than concrete.

Concrete would suck for a crucible. It would get brittle and crumble quickly. Also it would have to be 100% free of moisture before you use it or it would immediately crack open.

For Aluminum just use a steel pipe nipple with a cap screwed on one end. Or hit up Ebay and buy a proper crucible.

Or it'd build up pressure...and.... BOOM!!

Make one using ceramic, but air = bad. Just buy one for cheap(but good quality). Better then having a chunk of concrete in you right?

Or it'd build up pressure...and.... BOOM!!

Make one using ceramic, but air = bad. Just buy one for cheap(but good quality). Better then having a chunk of concrete in you right?

Ahh yes....I forgot that it would be just like making a fire ring out of rocks you pull out of a river or stream. Your crucible could turn into a fragmentation grenade or even worse a grenade full of molten metal.