Home made furnace questions

[MidFloridaTech]

I am looking to build a furnace. My plan it to use a Steel pot from Wal-Mart, then line it with refractory cement. I was planning on having a pipe running into it but haven't decided on a fuel yet. Is there a reason people use propane versus gasoline or oil with a venturi type setup? I am melting aluminum and brass/bronze only.

I am looking at these different cements but don't know the difference. It says its good to 2700* F so yea it should be plenty good. I think I'll go to Wal mart and get a steel pot and then make a furnace next or this weekend.

http://www.acehardware.com/product/i...Id=24416438094
http://www.acehardware.com/product/i...id=body_rv_img

[RBrandes]

I am assuming you plan to melt metal, no? If so then get over to
http://groups.yahoo.com/group/castinghobby
and join up before you make a big and costly mistake.
Here is a link to my foundry pages:
http://www.foundry.ray-vin.com/
where you can see the construction of my furnace and other casting items.

If you aren't planning on casting metals then please accept my apologies.

Regards, Ray in FLA

[Matt29c]

DO NOT use cement...It WILL explode...Use refractory mix (sometimes refered to as refractory cement, but it isnt cement at all) What I have for my furnace is a popcorn tin (like the ones you get around the holidays) and suspend a 5gallon bucket in it with equal space around, optional if you are using a burner (ie Propane burner or Oil burner) place a PVC pipe inside for the entrance hole of the burner (conects outside popcorn tin with inside 5gallon bucket) and fill with the refractrory mix you bought (fireplace stores and alot of hardeware stores have it you can also buy it online) mix according to the directions and pour it in the mold let it cure for 3-4days (or how ever long the mix directions say). The first fireing is VERY critical you must take it slow as to not allow the left over water inside the refractory mix to boil off to fast and explode. fire it on a low setting for 2-3hrs (or as long as the mix directions say) and then slowly bring it up to peak over the next 2hrs then turn it off and let it cool. When its cool retro fit the bottom of the furnace with firebircks to bring the crucible to the right height. And you are pretty much ready to melt low melting point allowys. Burners and the such are easy to make google search will come up with a 101 different types and styles. Oil burners are nice because they are mostly free just take a bit more engineering then propane. more info can be found at www.backyardmetalcasting.com. be safe and read up on what you want, then build it and have fun melting metal.

[307startup]

DO NOT use cement...It WILL explode...Use refractory mix (sometimes refered to as refractory cement, but it isnt cement at all) What I have for my furnace is a popcorn tin (like the ones you get around the holidays) and suspend a 5gallon bucket in it with equal space around, optional if you are using a burner (ie Propane burner or Oil burner) place a PVC pipe inside for the entrance hole of the burner (conects outside popcorn tin with inside 5gallon bucket) and fill with the refractrory mix you bought (fireplace stores and alot of hardeware stores have it you can also buy it online) mix according to the directions and pour it in the mold let it cure for 3-4days (or how ever long the mix directions say). The first fireing is VERY critical you must take it slow as to not allow the left over water inside the refractory mix to boil off to fast and explode. fire it on a low setting for 2-3hrs (or as long as the mix directions say) and then slowly bring it up to peak over the next 2hrs then turn it off and let it cool. When its cool retro fit the bottom of the furnace with firebircks to bring the crucible to the right height. And you are pretty much ready to melt low melting point allowys. Burners and the such are easy to make google search will come up with a 101 different types and styles. Oil burners are nice because they are mostly free just take a bit more engineering then propane. more info can be found at www.backyardmetalcasting.com. be safe and read up on what you want, then build it and have fun melting metal.

If you'd taken the time to view the links he provided, you'd have realized that he was indeed looking at refractory cement.

[bobk]

I built a blast furnace from a 16 gal. steel drum. I lined it with clay approx. 3 in. thick. It used charcoal for fuel, I could melt anything I wanted to and it was relatively safe. You must use extreme care when ever you try melting metals.

[teamtexas]

I made my home made furnace from an old propane tank and lined it with high temp inuslation, I coated that ith refactory cement. I made my crucible out of some scrap metal pipe I had laying around. I made a propane burner and use a tank like my BBQ uses. I was inspired by this link www.zoellerforge.com/simplegasforge.html check it out. Another good one www.abana.org/ronreil/design1.shtml

Here are a few pics of my furnace at work.

If your intrested I have whats left of the high temp insulation up for sale now on ebay.

Dan

[metalworkz]

Any updates to this thread? I made my furnace based on Dave Gingery's furnace book and the basic design as I made it is noted below. To get complete step by step info for the Gingery furnace you can get the book at :
http://www.lindsaybks.com/
You can make a good furnace fairly easily from a 5 gallon can. You will need to cut a tuyre(inlet hole about 1.25" dia) for the air blast just above the level of the inside base of the refractory. I have used old vacuum cleaners reversed and old style hair dryers with good results for the air blast source, and a simple valve can be included on the inlet pipe to allow for adjustment of the volume. Line the inside perimeter and base with about a 2.5 inches thick 50-50 mixture of fireclay and sand and add water to get a moist consistancy for filling the forms. There are also premixed refractories available but the cost is considerably more. Make sure the crucible or melting pot you will use will fit in the center and can be easily removed with tongs etc. You will need to make a form to hold the refractory in place while you fire the furnace to cure the lining. The lid can be made by making a sheetmetal ring(approx 3-3.5" high) for the outside perimeter and a suitable can can be used for the inside edge and weave a wire between the inside and oustside edges to add strength and hold their relative postions while the form is packed with the same 50-50 mixture of fireclay and sand. The lid can be fired(baked) in a kitchen oven and when done it can be placed on the body of the furnace and used to fire the furnace body with charcoal. Complete instructions available in Gignery's book, or contact me for more info.
Best regards,