Propane forge

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peppen108

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Apr 14, 2012
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I´m looking in to buying or building a propane torch. I found this one which is built by a guy. The camber is 6"x6"x16". The insulation is 2".

6865485718.jpg


Are the any obvious flaws whit the design?
 
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As a general blacksmithing forge that will work well.
As a bladesmithing forge, it has some issues.

Look for (or build) a forge with a tangential burner. That means it enters the chamber at an angle, and makes the flame swirl.
2" of insulation is excellent.
Fully open ends are not as good as ports on the ends. That isn't a deal breaker, as you can just stack or cut fire bricks to close off parts of the ends.
That forge will be harder to do any HT with, due to the two hot spots. A muffle pipe will help, but not eliminate the problem.

If the price and availability is best for you with that forge, it will be OK. Get about ten fire bricks from the seller to block the front and back and make "doors/ports".
 
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I found a video of a forge by the same maker.

[video=youtube;jSJAM30xPB4]http://www.youtube.com/watch?v=jSJAM30xPB4[/video]

The flame goes straight down. Could this be used to HT at all or am i better of whit a some bricks an a propane torch.
 
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That is what I was talking about. The straight down burners are less useful for HT.....but still far superior to a two brick forge.

The way to even out the heat is to use a piece of 2" pipe, which is called a muffle.

First, pre-heat the forge for ten minutes to fully soak the refractory liner. This will make for a more even heat distribution. The forge pressure should be turned down to run as close to the desired temperature as it can be regulated. For HT, that is almost at the flame out pressure for most venturi burners.
Then, place a long piece of pipe inside the forge. The pipe will keep the direct flames off the blade. Put the knife blade inside the pipe. Check the knife and move in and out as needed to get and even heating. When the blade reaches non-magnetic, heat a little redder, about 100°F hotter, and then quench. Canola oil will work if you don't have a commercial quenchant.
 
What Stacy is so delicately trying to say is a square forge it going to give you hot spots, not good for knife making. What you are looking for is something like this one I made. I am going to provide you some links.

The angle of the burners is what you need to keep in mind as some of these links do not use an angled burner. The angle keeps it from be focused directly on the blade steel and creates a vortex effect inside the forge! My forge origionally had the burners designed straight into the side. A well known knife maker Ed Caffery was looking at a picture of it and clued me in that I was going to have hot spots with the burner design. I cut the holes for the burners out and patched the tube and re-welded them at the angle you see in the pic. I have never looked back and am so glad I did that before I lined the forge.


click on tumbnails for larger view:








My forge has been ever evolving. It has been moved to what I affectionately like to call the "War Wagon".






It is now in the process of being reworked to be run by a PID and controlled with a solenoid gas valve, thanks in no small part to all the advice and help by our own Stacy! When I finally get it all done and hooked up and running I will post some new photo's of the whole set-up!

http://www.bladeforums.com/forums/s...-a-gas-Solenoid-Valve?p=10627685#post10627685


If you are proficient in welding and ask a few questions you can build your own! Here are some links to some ideas on building one an the different burners you can build and buy, as well as a few sites you can buy materials.



http://fredlyfx.com/large propane.htm

http://fredlyfx.com/progress.htm

http://ronreil.abana.org/design2.shtml

http://zoellerforge.com/

http://www.rayrogers.com/blower.htm

http://www.ccallis.com/black_iron_fittings.htm

http://www.cornerhardware.com/index...page=2&zenid=a322a34851d7fbdaf37b41fc4b9dbf6a

http://www.arscives.com/bladesign/forge.tutorial.htm

I hope all this info helps and feel free to contact me if I can give some more info or just fill in the blanks!
 
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That is awfully nice! I will look in to the last links tonight.

I have some drawings on a forge where the muffler is indirectly heated mad by Tubal Cain. He says that he has maximized the furnace fore one burner and the muffler tube is only 6" so i guess 4" blades is about what you can heat. This is a rough sketch.

ugn.png
 
Some language barriers need clearing up:
You have already found out that the device to make and heat treating a blade is a FORGE.
The tube down the center of a forge when doing Heat treatment is called a MUFFLE.

If that forge is only 6" long, it is too small to do much.
I would suggest a forge with a 12" to 16" length. A 12" forge can run on one burner, and a 16" forge does well on two.
 
I am sorry the pic i posted was of another forge. The one in the first post seems to be less suited fore HT than i hoped (fore the reasons bladsmth
stated).

Thanks fore the help every one.
 
One safety point- make sure the pipe you use as a muffle is not galvanized. Black pipe only. Galvanized emits vapors that are dangerous to your health
 
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