Metal Casting Zone

Hey guys,
i'm fairly new to this whole field and the first furnace i tried to make with charcoal ended up melting the entire project until aluminium caame out the ventilation tube. I have designed a project for a electric furnace but now just before construction, i have second thoughts over my design and the potential dangers of performing the heating with electrical heating elements.

My desing is a large flowerpot with a tin in the middle wrapped in the heating element. out side the tin will be covered with ciment fondu as insulation. when dry the tin is gently removed, leaving the element inside around the outside of the heating chamber. My fear is the electricity. Making sure there is no contact with the sides whatsoever to avoid 240V.

Does anyone know what would insulate the electricity but not the heat capable of melting aluminium?

or is this just a bad idea altogether???

What type of elements are you using, a kiln type coil or an oven element? You always have to be careful with the electric, insulate everything outside the furnace and use high temp appliance wire for the connections. Always turn the power off before reaching inside the furnace with tongs or anything metal.

Welcome to the form.

Hi Pickle_64,

Why don't you stay with the charcoal furnace? at least you know it will melt your metal, you just need a better crusible.

As for the electric furnace I think you may use a lot of power to not melt much metal. I am not sure what your concern is, the refractory in which you cast the heating element will electrically insulate it, and providing the element does not touch itself from wrap to wrap there should be no short circate there. You do need to ensure the refractory is perfectly dry befor you atempt to melt metal.

What crucible are you intending useing in this furnace?

Good luck (you may need it)

Peter.

My main focus with electricity was the cleanliness of the process relative to some others. I'm not scared of a short circuit between loops of coils(i'm using coils by the way) but i am most fearful of an earth leakage which involves me forgetting to turn the power off once, reaching with tongs, contact being made with the live element and me going into cardiac arrest from 15 amps at 240v.

recently after posting, i managed to see kits for sale at lost and foundry for gas furnaces, which made me wonder whether in your opinions, for someone who has never operated a furnace except for a coffee tin which was highly uncontrolled charcoal powered, should my furnace be storebought and perhaps build a furnace later down the line when i have more experience and knowlege in this area? (long sentence)

Thanks for the Welcome.
I live in Newcastle, Australia and i'm a trainee electrical engineer for Energy Australia.

Hi Pickle_64,

As you are making the furnace I would expect you will make your own tongs, why not insulate the handels, a piece of old hose should do.

Wether you build a furnace or buy a kit is up to you and your finances. There are some good books on casting which cover furnace building, have you read any/many of these?

Peter.

yeah,, i've looked around in several websites for books about construction but am now feeling a purchase is the better option.