Mini Charcoal Furnace

Step 11 This was a fun experiment !!! Some conclusions

As I predicted my furnace started to crack after more meltings. Before it will "die" I hope to get a small object sand casting. And after that I'll scrap this furnace and make a bigger and better one.

I don't recommend using tin cans at all, it can be dangerous, I got a few ingots out of it but one corn can I used broke inside the furnace with big holes.

This was a great experiment for first time aluminium casting.
Hope you enjoyed my instructable.

This is a short video I made, I know its not great and my hand is in the way and a bit of slag fell  into the muffin tray but it gives the general idea of ingot making.

Comments

[bobbuilder09]

hello,

i am sure i read somewhere that if the inner refactory mix is not to thick, and then surounded by a layer of sand (allows expansion) or probably ceramic wool, then a further layer of refactory insutation, then a expandable layer (you get the onion ring effect idea) then the refactory layers are allowed to expand and contract without too much stress and therefore cracking. i think some experimentation is needed.

to hold the solid layers together(at the top), some wire netting, or stainless steel wire in a zig zag fashion around the circumference (binding)between the layers would bind the whole lot together, whilst allowing expansion,

just food for thought

[Lambskin]

Can you melt copper with it?

[didgitalpunk]

very nice instructables! i started making a forge about threedays ago the crucible i made is a 5mm steel oxygen bottle an the forge itself is an old propane bottle( the one i used is about 50cm in diameter)

[NutandBolt]

Hi thanks for your comment, I think you made great crucible I was using beans can for my first few melts and that is a bad idea although I got away making a few ingots befor holes appeared. So 5mm thick steel sounds great. I am in the stage of scraping my furnace and making a proper one with proper refractory using the same old propane gas tank as you are planing to use. Regarding the paint don't worry about all the impurities once you get your high tempature and the aluminum is ready to be poured you just have to remove all the slag with fork or some other great instrument. It would be great if you can post a few images of your crucible/furnace. Thanks again :-)

[didgitalpunk]

thanks for the tips! yhea i'll try to post some videos of what i did but it'll take about two weeks but i wont forget! thank again!

[didgitalpunk]

ho yeah i forgot. if you put aluminum with paint on it, does the paint burn and desintegrates or does it form slag? thnksfor answering!

[greenfreak]

dude! this is great!.... im gunna build one when i get some more cement! and im gunna use a metal box to keep it more sturdy!... thanks so much for the instructable!

[NutandBolt]

You are welcomed, My next furnace I will build in metal box too. I agree it's much more sturdy. If you do build one post some images.

[greenfreak]

alright man! will do...

[ld2i]

Very well written, one of the best furnace/forge articles I've read. I'll be sure to try this once I get my hands on some materials. I have a couple of questions though if you would be so kind: Is it possible to use normal cement, or does it have to be the special refectory cement? And also, would this work to melt aluminum cans as well, or would those just disintegrate?

[NutandBolt]

Thank you very much I appreciate you positve comment . If you use normal cement the furnace will probably crack. As you can see in my last images after a few uses.
You can place the cement in some metal container, the container will probably prolong the furnace life. You can google furnace refractory mix and you will see many sites that provide guides for the proper materials and mix ratio.
Most people start by melting cans the only thing is you need a lot of cans to get some decent amount of molten aluminium. And the cans produce alot of slag that have to be removed.
I would recommend melting some aluminium objects that you have no use for they will give you more molten aluminium.

[ld2i]

Ah, I see. I'll look into that then. Thanks for the help, I appreciate it.