Anyone ever tried slip casting their own crucibles? https://www.google.com/url?sa=t&sou...FjAMegQICBAB&usg=AOvVaw2Nc3zQP1YNKGxlTfjGrnM8
There are some threads here (or was it AA?) where people have made their own crucibles, also some youtube videos I've seen as well, but none that were slip cast as I recall.. The take-away I got was that if I had no other way of getting one a usable one could be rammed up, but that I would rather fork over some cash and save the trouble.
Couple of guys on AA made crucibles, I seem to recall thermal conductivity was just one of the issues.
I'm checking out stuff sitting around my man-space, aluminum hydroxide, zirconia silicate, silica carbide, bone ash, kaolin, fire clay, cmc gum, veegum, and some other such paraphernalia. Thinking, "how hard can it possibly be to do something like make my own high temp crucible?" This type of thinking is one of the key benefits of complete ignorance on a given topic. Ok, maybe take a baby step and make a liner or wash that will extend the life of my crucibles. Guess I'll have to do some digging, reading, perhaps experimentation.
That's funny.....but so true! IMO, this is one area where you're better off buying, especially if you have iron in your sites. Here's A thread that kicks it around. The AA links are dead. http://forums.thehomefoundry.org/in...hips-homemade-crucibles-the-story-so-far.476/ Best, Kelly
Yeah, I imagine that one can’t use insulating material like alumina or zirconium oxide. However, if graphite or silica carbide-based, I’d think that thermal conductivity wouldn’t be a problem. Seems like challenge is finding a good binder. A lot of graphite crucibles use fire clay. I don’t understand how these crucibles withstand iron melting temps. Even high-fire clays have melting temps less than 2800F except those that contain insulating materials like alumina or zirconium (I think).
I'm sure it has been done and maybe you can do it, but I'd just pay the man! I'd hate to see the bottom fall out on you above your feet. We would have to change your name here to STUMPY!
I ran down this rabbit hole. Turned a wooden plug for A4 , cast a POP mould, and then slip cast Mullite. A friends wife is a potter, so he fired it for me in her oven. The failures were: - The mullite needed too much water, therefore it only slip cast to a wall thickness of about 6mm (1/4") I believe the way around that is to use a sodium silicate solution. - It got a shrink tear on the inner lower corner during drying. I tried to dry it nice an slowly over days, but it still tore. The moisture gradient between the outside which lost it's moisture to the POP mould, and the inside is severe. - For some reason I cant remember, it is not full height. Maybe it cracked on the lip so I had to trim it? - I smoothed over the tear, but it caused a crack during firing. I let my kid paint it for easter, and use it as a pot plant vase. For aluminium, a thick walled steel pipe crucible is safe enough, even if it does contaminate the alloy a bit, so I was really looking for a crucible for iron and bronze. Seeing the result of my efforts pushed me to just buy quality crucibles, and minimise that safety risk.
I took a photo of that A4 mullite crucible. Doesnt really show much, as the pot plant left too much gunge in it to see the crack.
Checking out vids linked to by @Al2O3 and other similar vids, appears that more popular approaches are vibrating and/or ramming crucible material into mold creating thicker walls. Thickness would need to be uniform. After watching vids, I think that this might be easier than slip casting. After thinking about issue, I agree with earlier comments it’s that cheaper and more reliable to purchase crucible if using clay/graphite. However, I might experiment with making crucible liners, maybe silica carbide. Shrinkage and fragility are still problems. Been reading up on topic, but don’t have a good solution yet.
