Author Topic: Propane Tank Furnace/Forge  (Read 5037 times)

Offline Will_D

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Propane Tank Furnace/Forge
« on: March 09, 2015, 05:27:43 PM »
I have just picked up a 42 lb Propane tank. (I think it is a 19 Kg one and it is 830 mm tall.

Anyway its bigger than the normal 11 Kg ones that have been modded.

So applying a bit of lateral thought I came up with this mod:



It can be Coke/Charcoal fired or Propane fired for furnace use.

Pop in the grate and load up some coke, add the extension collar and its a forge. For serious forge welding pop on the lid. The various cutouts/holes in the extension are just to support long bits that need to be held in place without having to hold them! (Like long tongs!)

Mad or what?

All comments sugestions are VERY welcome before comitting
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Offline vtsteam

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Re: Propane Tank Furnace/Forge
« Reply #1 on: March 09, 2015, 07:29:02 PM »
Looks pretty good to me Will. The only thing that might be different in what I like, personally, for a small furnace this size is about 12" of internal bore height to fit in enough charcoal not to have to pull out the crucible and renew fuel when melting say 5 lbs of aluminum. There's plenty of room for a propane furnace, but solid fuel does take up space.

I shoot for 2" refractory in a 12" diam. shell and a bore of 8" seems to work well for me.

For my bigger oil burning Iron furnace and firebrick lining I went with 4" refractory thickness, and ended up with about 7 to 7-1/2" bore, as I remember it. It is a little tight getting tongs in there around an A-6 crucible, and I wished it was 8".

But your plan to use it for a forge, too seems like it would work fine.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

RobWilson

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Re: Propane Tank Furnace/Forge
« Reply #2 on: March 10, 2015, 04:51:15 PM »
Hi Will


If your planning on coke firing , drop the blast hole to an inch from the bottom and have it come in parallel , also you will need a grate about 2" , 3" inches from the bottom . fill with coke and fire ,let burn down , this pre heats furnace . then pack with coke until crucible top is 1/2 inch bellow furnace top and pack round with coke , charge with metal (cast iron ) and give it plenty of blast . The charge of coke will burn down and the crucible sink down as the fuel is used , you may need to reposition the crucible form time to time (it may tilt a tad)


Rob   

Offline vtsteam

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Re: Propane Tank Furnace/Forge
« Reply #3 on: March 10, 2015, 07:32:02 PM »
iron? Will, were you planning to melt iron, or was it aluminum?
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline Will_D

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Re: Propane Tank Furnace/Forge
« Reply #4 on: March 11, 2015, 05:26:37 AM »
I didn't mention iron!

Aluminium first then maybe brasses and the like.

I may never get round to Iron - Its scary stuff!

But thanks for all the great suggestions.
Engineer and Chemist to the NHC.ie
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Offline vtsteam

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Re: Propane Tank Furnace/Forge
« Reply #5 on: March 11, 2015, 08:26:38 AM »
Well, you could, if you follow Rob's instructions and used a suitable high temp refractory. But not with plaster of Paris (if you were considering it). And my suggestions were only based on melting aluminum w/ charcoal briquets or propane. I, like Rob, also just run the tuyere near the bottom and straight in vs. angled up. I do angle it somewhat tangentially -- more for propane than charcoal.

I know you're worried about spills running down the tuyere, but with small quantities of aluminum, I think the hazzards can be exaggerated in online reading. And if you're over a good bed of sand I'm not sure having the aluminum solidify in the well is preferable to having it run out into a sand basin.

The blast pipe on mine is aluminum tube, and I doubt a serious leak of aluminum would make it to the blower, and a slight angle on the blast pipe is enough to guarantee it won't. Otherwise, with a steep tuyere as you show, the blower has to be situated and angled down from above, which is awkward.

The tuyere on mine is maybe a half inch above the bottom, which if you multiply times an 8 inch bore, is a fair amount of containing volume anyway, and most leaks from a metal crucible are relatively slow. I guess if you shattered a ceramic version it could go fast, but hard to imagine how that would happen with such totality.  When new to casting, fear of the unknown tends to exaggerate concerns, but really this is a tiny amount of metal compared to even small scale commercial practice. I'm not trying to minimize caution, but if reasonable, things will go well.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg