Electric Furnace Build

[Jelly]

Ok, I shouldn't post without actually having something to show. But I want to make a small electric furnace as the pollution laws up here in Washington are pretty strict.

My idea is to use a propane tank for the shell, order some kanthal elements, some sort of automatic temperature control that I can select the heat. Thermocouple/LCD readout. I'll clean this thread up later and add pictures as i find things I want to do

Things I need to get:

Propane tank Shell
Insulated Fire Brick Locally 2.50 a brick.
Kanthal element
Some Type of High temp paint
Thermostat
Temperature Gauge (LCD/Analong, dont care really)
High temp Cord and Connections

I read these Insulated fire bricks can be cut with a skill saw, table saw, other method of sawing but more time is required. I'm not sure what the exact specs are so im not sure if they are hard brick or not.

[GypsyTinker]

I look forward to seeing it! Not enough electric furnaces if you ask me. I think it is super super cheap to run.

[Nudge]

Not as cheap as oil but I understand why you need to go electric. What I do like about them is how clean they are.

Thumbs up for a build

[davidbraley]

If you live in an area where the electricity is cheap, then I imagine it's a great way to go.

All the electricity around here is generated with fossil fuel....

[Nudge]

it's mostly like that here too

[dallen]

Things I need to get:

Propane tank Shell
Insulated Fire Brick Locally 2.50 a brick.
Kanthal element
Some Type of High temp paint
Thermostat
Temperature Gauge (LCD/Analong, dont care really)
High temp Cord and Connections

I read these Insulated fire bricks can be cut with a skill saw, table saw, other method of sawing but more time is required. I'm not sure what the exact specs are so im not sure if they are hard brick or not.

Wear a resperator when cutting the brick, stuffs nasty in the lungs.

heres a link for a place thats reasonable on elements http://www.infraredheaters.com/ They also have an online calculator that you can use. just a thought, I know a guy in Oregon that bought his PID from Cold Fusion I belive out of San Francisco

Instead of going to all the trouble to build a complete furnace why not see if you can find a kiln that someone wants to get rid of, sometimes they are given away as people don't know how to fix em or are just tired of them.

David

[Bull]

I was thinking of trying electric myself! I have the tank and bricks so far....do you guys think I should make an insulation layer behind the bricks?

[Harry]

What kind of bricks do you have Bull? There are the really light ones that feel like you are holding air and carve very easily, these are great insulators on their own. The heavier furnace brick is almost as heavy as a regular fireplace brick and a lot tougher than the insulating brick, these probably would not be too good to use for an electric furnace because they would suck so much of the heat away.

Of course I have never built an electric so this is just my guessin' Would like to have one though, problem here is electric is high.

[Bull]

ah yeah, I have the dense bricks....but I can easily go buy some of the light ones. I was thinking of backing the bricks with a homebrew insulation of fireclay, sand and perlite. I was just wondering cause ShadowFangs didn't have it on his list!
Also, do think a cheap thermocouple mounted inside would last very long? I figured you could at least know the ambient temp inside the furnace to judge the metal temp by. I enjoy building things so I'll probably end up with several furnaces before I find my "go to". I hope I'm not highjacking this thread....but it seemed appropriate to ask the wise sages here!

[Harry]

Like I said I havent built an electric furnace but I do have an opinion I would not mess with the dense bricks, seems to me it would just end up costing more in power to run the furnace over time.

I will leave it to those wise sages you mentioned to offer better informed advice. The thermocouple should be ok, you probably want some kind of protective ceramic sleeve for it.