Starting my first and only electric foundry build

Hi DIY and welcome to the forum.

First off, I'd say a big no to the materials you suggest for the refractory. PoP and concrete have no place in a foundry furnace. Use real refractory, at least for the hot face. I'd skip the steel wool too but some use stainless steel needles. I use an electric furnace for aluminum. You can see my build at the link in my signature of this post and also a recent rebuild I did at the link below in this forum. My furnace is a bit elaborate but suits me. There is a lot of information in the build threads that may be useful to you. I wind my own coils and there is discussion and video of my coil winder in the build threads. I used Kanthal A1. If you are only going to melt aluminum you could also use NiCr60 or other NiCr alloys. Kanthal A1 has higher max operating temp but it doesn't maintain it's mechanical properties as well at those temps and you don't need that temp capability for aluminum. I operate my furnace at 1800-1900F for aluminum melts and it performs fine. There is at least one other electric build posted here as well. Do some searching and reading and come back to us. How much aluminum do you want to be able to melt and pour in a single shot?

http://forums.thehomefoundry.org/index.php?threads/furnace-fail-reconstruction.209/

Scott K took a different approach which may also be of interest to you.

http://forums.thehomefoundry.org/index.php?threads/homemade-electric-furnace.80/
http://forums.thehomefoundry.org/index.php?threads/how-i-am-making-an-electric-furnace.81/

Best,
Kelly

 

Welcome to TheHomeFoundry!

It's called 'castable refractory', but not to be confused with the stuff at (ie.) Lowe's that is meant for patching cracks in wood stove bricks - you won't find it in big box stores at all. It comes in powder form in 50-55lb bags; some very popular brand names are Mizzou and Kast-O-Lite, and those are rated for really high temperature work up to and including cast iron. You may never plan on melting iron or even copper alloys, but you would not regret using these high quality materials if you really want this to be your last furnace build. I built my (waste oil-fired) furnace using a brand called Unicast-70 for the innermost layer, rated to 3200F, because that is the type of refractory my foundry products supplier carries. I'm very happy with it, I've melted aluminum many times and done a couple of bronze melts, and it just laughs at what I have come to think of as "heat".

Another option would be to use insulating firebricks, like they build ceramics kilns out of. You should be able to get them from a local pottery supplies business, but you may need to ask them about it to find out as in my experience their websites tend not to list every product they can order in or even that they keep in stock. They're very easy to shape and work with, but they are quite fragile.

Casting steel is said to be out of reach for the vast majority of home gamers. Melting it... maybe... but probably not successfully casting it. That is the usual answer to that question anyhow.

Good luck!

Jeff

 

This eBay seller offers a lot of different refractory material. Shipping is a killer so it pays to find local sources.

http://stores.ebay.com/HIGH-TEMP-REFRACTORY-STORE?_trksid=p2047675.l2563

Electric is ok if you are going to melt aluminum but you'll want a fuel fired furnace for higher melt point alloys. Steel is unlikely for the home gamer. Iron is possible but not a good starting point for the inexperienced. You also wont likely start off melting an entire cylinder head at one time and will want to build a crucible furnace. The crucible holds the molten metal. More research for you to do!

Best,
Kelly

 

I drove 5 hours each way to get my refractory, and only later found out the local pottery supply business where I got my ceramic fiber blanket and insulating firebrick could have special ordered it for me, which I forgot to mention above. I had reason to make that 10h round trip anyhow when I got mine (visiting a friend for the weekend), but even if I hadn't, the hour-long tour that company owner Tim of Smelko Foundry Products' gave me of his warehouse alone was worth every kilometer.

This question actually comes up commonly. Many have recommended getting in touch with guys who install/repair boilers, hinting that opened but only partially used bags of the stuff might be had off the back of a truck at a work site for the price of a 6-pack if not for free. So there may be some good castable refractory closer than you think, if you talk to the right people...

Jeff

 

It's ok to start off with a steel crucible but I'd suggest you build your furnace to accommodate a proper clay graphite or Silicon Carbide crucible.......you'll be glad you did if you progress in foundry practice. I'm not familiar with that particular Refractory but have used other HW products. You might also consider buying some ceramic wool for insulation. Are you still thinking electric or fuel fired burner?

I didn't realize Harbison Walker had a retail Amazon store front. Here's the link from DIY's post. This might be useful to those with no local sources. Now, if you were a Amazon Prime member and could get 55lb bags with free shipping what a treat that would be. The prices with free shipping at that site are amplified to cover shipping.

https://www.amazon.com/s?marketplac...YVW6BQGA&merchant=AI420YVW6BQGA&redirect=true

Best,
Kelly

 

I don't know anything about that variety either, but this one is similarly priced and comes very highly recommended:
https://www.amazon.com/MIZZOU-CASTA...rd_wg=VK5lP&psc=1&refRID=M3ETVGN9S9J1BDWW1253

You could always just use insulating firebrick. If you're careful not to ding it too much with your crucible tongs, this may hold up quite well since in an electric furnace you won't have a burner blasting right onto it. The light bricks are also very easy to carve grooves into for holding the coils. With the ceramic fiber blanket option, you'd definitely want to seal in the insulation behind something that will keep the fibers from going airborne and being inhaled.

Jeff