ramsies11 Posted February 13, 2012 Share Posted February 13, 2012 i know people use flower pots as a foundry, so if i can find one without a hole in the bottom, can i use it as a crucible? and if i cant find one without a hole, my local wally world sells oven bake modeling clay, can i form a crucible/ use that to patch the hole in the bottom? Quote Link to comment Share on other sites More sharing options...
oof Posted February 13, 2012 Share Posted February 13, 2012 most of the flowerpot furnaces crack on the first firing or two. oven bake clays(that i'm familiar with) are polymer clays, and may burn out at those temps. you don't want your crucible pouring out the bottom especially if you're pulling it out of your forge and have it lifted higher than your belly button. if your doing aluminum, steel is a safer way to go. weld a bottom on a piece of pipe, then heat it in the fire to red and cool before use. the oxide layer will help prevent the molten aluminum from disolving the steel. it will still contaminate the melt with iron a little. some are having success with dense castable in a form for making crucibles capable of bronze temps. i've made a crucible out of ramable refractory (noxram) after a friend of mine mentioned his success with it. i've fired it and it rings but i haven't tried it yet. just be aware of the risks....a pocket full of molten metal makes for a bad day. mark Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 13, 2012 Share Posted February 13, 2012 Having melted a terracotta flowerpot in my forge trying to use it for an enameling furnace and having worked with molten metals quite a bit may I say ***************NO!******************* Trying to save money on your crucible is much like using someone working out of their garage for surgery---you will be very lucky to be able to complain afterwards! BTAIM I have used thick walled stainless steel creamers to melt small amounts (several ounces at a time) of silver or brass or bronze in my forge for pouring. Note that these degrade fairly fast. One particularly thick one lasted for four pours! If you are not trained in the safety issues involving molten metal PLEASE find someone who can show you what's involved; there are backyard metal casters everywhere and working with someone who knows what they are doing can save you a world of hurt! I consider molten metal to be much more dangerous than steel that's hundreds of degrees hotter---and I've worked with both! Quote Link to comment Share on other sites More sharing options...
LeeMcKee Posted February 13, 2012 Share Posted February 13, 2012 I agree Thomas... In fact, lower temp metals such as Aluminum or even Pewter will cause MORE damage than cast iron. when it does hit you it sticks instead of being forced away by the steam it creates like iron would....there is nothing worse than having to sit there and take the pain as you slowly put down the ladle before "peeling" the metal off of you, with plenty of skin of course.... Ramsies... Forge a small ladle and melt a couple of small chunks of Aluminum over the forge. wear safety glasses, welding gloves and an apron when doing so. You can make a mould out of a cuttlefish bone that can be purchased at any pet supply for birds. Read, Read, Read, as much info about casting as possible and particularly concerning foundry safety. Start small and work your way up as you skills increase. There are people in your area that cast professionally for sure... go and tour their foundry and if you interested enough ask to apprentice there. That is the only way to learn... Quote Link to comment Share on other sites More sharing options...
MattBower Posted February 13, 2012 Share Posted February 13, 2012 Flower pots were never intended to take the kind of thermal shock that crucibles endure. They also melt at much lower temperatures than refractory ceramics, and they're not intended to retain strength at high temperatures. Flower pot furnaces are typically lined with some kind of refractory mixture; if they're not, then, as oof said, they won't last long. So no, NO, A THOUSAND TIMES NO. Glad you asked. And no, oven bake "clays" are not going to do the trick, either. (I put "clays" in quotes because I'm not sure they contain actual clay. Even if they do, what's holding them together is not sintering of the ceramic particles, as in any normally fired ceramic.) Small commercial crucibles can be had for decent prices. http://www.lmine.com...budget_graphite Note that there is a curing or "tempering" process for clay-graphite crucibles, which you should follow before each melt to gently drive off any absorbed moisture before taking the crucible to metal melting temperatures. Quote Link to comment Share on other sites More sharing options...
dan_m Posted February 13, 2012 Share Posted February 13, 2012 As everyone else said, the answer is no. A steel pipe welded to a plate for the bottom works well for aluminum, but only if you have a welder. If you don't, I'd just order a small crucible, but if you need to go an even cheaper route, a stainless steel container will work as Thomas suggested. Check the kitchen section of thrift stores. A soup can can be used successfully for small amounts of aluminum, I've done it but can't recommend it as its really pushing the limit. If you try that, don't reuse the can, but really a stainless container should run you a dollar or two secondhand, and the small commercial crucibles really are cheap enough to make it not worth the hassle to even mess around with anything else. Plus it should last indefinitely for occasional melting of low temp metals. Quote Link to comment Share on other sites More sharing options...
OddDuck Posted February 14, 2012 Share Posted February 14, 2012 I'll second Matt, don't do it. Like I told ya in our PM's about this, find yourself a cast iron saucepan, or a chunk of iron pipe with a cap or welded bottom (find a buddy who is a good welder, it should be able to hold water without leaking). I'll un-recommend stainless kitchen anything, I've tried them and they aren't worth even the couple of bux they'll cost you. They last one or two melts at the most and then spring a leak. Stainless does nothing for you at those temps. I know you really really want to try this out, but shortcuts will discourage you due to imminent failure. I've tried a lot of the options that you have put forth, they have been abandoned for good reasons. Like Matt said, check out Ledgend Mine, you can get an economy fireclay crucible for under $20 (before shipping...) and their budget clay-graphite #8 crucibles go for a whopping $28 or so. It'll probably cost that much in welding rod by the time you get a good one made out of pipe. I kid you not, this will save you a bunch of time and heartache, and allow you to learn the actual craft of foundrywork instead of just getting the thing to work. Quote Link to comment Share on other sites More sharing options...
ramsies11 Posted February 15, 2012 Author Share Posted February 15, 2012 i mainly started this as a question of wonderance. but heres my second question, what can i use for an ignot mould? Quote Link to comment Share on other sites More sharing options...
cvmikeray Posted February 15, 2012 Share Posted February 15, 2012 Not an endorsement - just a source I know has casting stuff.http://www.piehtoolco.com/contents/en-us/d834.html Quote Link to comment Share on other sites More sharing options...
MattBower Posted February 15, 2012 Share Posted February 15, 2012 i mainly started this as a question of wonderance. but heres my second question, what can i use for an ignot mould? It's pretty common to use a cast iron muffin tin as an ingot mold. If you know anyone who can weld, you can also make ingot molds from pieces of channel or angle iron. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 16, 2012 Share Posted February 16, 2012 Ingot mold depends a bit on what you are melting and pouring too Quote Link to comment Share on other sites More sharing options...
LeeMcKee Posted February 17, 2012 Share Posted February 17, 2012 I had a ton of car rims to render down into ingots....here is my ingot moulds and such Quote Link to comment Share on other sites More sharing options...
ramsies11 Posted February 18, 2012 Author Share Posted February 18, 2012 lee, that looks neat!i like your array of ingot moulds. are they all cast iron? Quote Link to comment Share on other sites More sharing options...
OddDuck Posted February 20, 2012 Share Posted February 20, 2012 The simplest and most versatile (and dirt cheapest) no-weld crucible mold is just a half-flask filled with greensand and ingot sized depressions pressed or carved in. Infinitely re-useable, you can make as many as you have sand for, and if you are careful when you remove your ingots, reuseable without having to redo it. Quote Link to comment Share on other sites More sharing options...
ramsies11 Posted February 21, 2012 Author Share Posted February 21, 2012 thank you all for your help. id like to close this topic now to keep people from commenting anymore on it. Quote Link to comment Share on other sites More sharing options...
Guest Posted February 21, 2012 Share Posted February 21, 2012 It does not work that way Ramsies, this thread stays open. Quote Link to comment Share on other sites More sharing options...
John Jacob Jinglehimersmet Posted December 2, 2021 Share Posted December 2, 2021 (edited) xxxx xxx to you friend! terracotta pots are fired at 2,000 it's not like molding clay. Terracotta is capable of handling 5000 degrees gold melts at around 1800. Clay was the original form of foundry smelting pot . But you do have to be careful for thermal shock! Edited December 2, 2021 by Mod30 Language Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted December 2, 2021 Share Posted December 2, 2021 Terra cotta is considered a low fired clay; I once tried using a pot to make an enameling furnace in my forge and ended up boiling it. I do not believe your information is accurate based on research and personal experience. Porcelain is a high fired clay. Also many ceramics do not deal well with thermal shock so take that in consideration when using them. Quote Link to comment Share on other sites More sharing options...
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