Building a propane forge.... Help, I dont want to blow myself up!

[Dustin Stephens 1]

So I have decided to build a firebrick forge, loosely on the zoeller forge design. I was wondering if it would be better to build my burner or just buy one... My forge will be roughly 175-200 cubic inches chamber diameter so Ill only need one. Anyone on here good at burner building? Good reference material? ect... thanks in advance

[C.Anderson 13]

I just recently built a burner for about $29 in parts, including all of the brass pieces from the ball valve forward. The end result works well enough, though i haven't done any adjusting so I don't know if it will weld when done. I already had a POL adapter and a regulator so it was just a matter of a hose with adapters, the ball valve, a 90, brass nipple, mig tip, a 1 1/4" x 1/8" reducer, the 1 1/4' x 3/4" x 1 1/4" tee, and the remaining burner tube parts. It burns quick and clean from about 1psi to 17psi. My forge is about 300ci, but where I have the burner placed is for heat treating and basic forge work rather than best heat.

Here's a short video. Building the burner was a lot easier than it seems up front.

And a few pictures of the burner parts. The only thing I didn't get quite how I wanted it was adapting the 1/8" brass nipple to the mig tip. Currently I have a weird adapter piece in there, but I'd like to make something a bit more solid.


Burner parts.


Assembled.

In the forge.


All warmed up at about 12psi.

A few notes:

-I don't have any ITC lining, just satanite.
-I didn't use a burner flare, just molded it into the upper hole in my kaowool with satanite and a shaped dowel.

-I have the parts for a second burner if I wish, and have a few holes setup in my forge to move the burners around for different operations. I can put a swirl flame in by running the burners on a tangent, or directly down, in three separate positions.

Hope that helps!

Edited January 26, 2016 by C.Anderson

[Dustin Stephens 1]

saweet!! I think i can do it. just have to be very very careful. No beers during this build:)

[C.Anderson 13]

saweet!! I think i can do it. just have to be very very careful. No beers during this build:)

 

Yep lol. the only modification was tapping the inside of the weird little adapter for the mig tip, and drilling out the 1/2" x 1/8" brass adapter so the brass nipple would slide through. Outside of that it was literally a screw together deal.

[Wes Detrick 482]

Cris,

What you built looks pretty much like a sidearm burner minus the flare. I have two in my forge, and they will get to welding heat. Takes a shitload of gas, but I think that is due to my forge rather than the capabilities of the torches.

[C.Anderson 13]

Cris,

What you built looks pretty much like a sidearm burner minus the flare. I have two in my forge, and they will get to welding heat. Takes a shitload of gas, but I think that is due to my forge rather than the capabilities of the torches.

Pretty much, yep! The flare is built into the forge lining though...so it won't wear out . I've still got to learn to tune the things...but they definitely get hot, that's for sure.

 

What mig tips/orifice are you using, out of curiosity?

[Jerrod Miller 333]

I tried a welding tip like the one in the second picture Chris posted, but had problems and switched to a taper tip with wonderful improvements. I had got a sweet deal on the blunter tips, so I just tossed one in a lathe and added the taper, but if you're buying one to begin with I would get something that looks like this one. Also, this thread may be of interest here.

[C.Anderson 13]

Hey there Jerrod!

Is there any real benefit to the taper tips? I was actually hoping I could find a tip that I could screw directly into the tapped 1/8" nipple. I hate having a junction there!

[Jerrod Miller 333]

I definitely noticed a huge difference with the tapered tip. I still need to adjust my nozzle tip to get closer to the burner tube, as it is currently closer to the middle of the T opening. My initial trials didn't show a noticeable difference moving the tip depth. After some other adjustments I think it is time to revisit the tip placement. How does one talk about this without sounding dirty?

[C.Anderson 13]

Nose my friend...the nose placement lol.

I haven't adjusted where my injection NOSE is either lol. Something I definitely need to do .

[Dustin Stephens 1]

Very good deal! Thanks Cris and Jared, if I happen to die, dont let my wife sell my guns for what I told her I paid for them! Next, Ive been kicking around the idea of which insulator to use. Is the insulating fire brick or the wool/ceramic blanket stuff better?

[C.Anderson 13]

I used blanket because it's much easier to form. That said, if you do so be sure you coat it with satanite or some other refractory mortar. Breathing in little pieces of refractory blanket is very, very bad for you.

[Jerrod Miller 333]

Blanket is generally used because it is so easy to shape, but if you want a squared forge, or something self supporting then you can use brick. There are pros and cons to each. Both my gas forges are blanket lined.

[C.Anderson 13]

I tried a welding tip like the one in the second picture Chris posted, but had problems and switched to a taper tip with wonderful improvements. I had got a sweet deal on the blunter tips, so I just tossed one in a lathe and added the taper, but if you're buying one to begin with I would get something that looks like this one. Also, this thread may be of interest here.

I was looking around Grainger, and found these as well, which might work better as I believe they are the right diameter to just screw into the 1/8" nipple:

 

https://www.grainger.com/product/AMERICAN-TORCH-TIP-Contact-Tip-45G045?functionCode=P2IDP2PCP

 

In addition, they come in packages of 5 for $12 lol. I'm running .036" now....but I'm curious what all you guys are running.

Edited January 27, 2016 by C.Anderson

[Dustin Stephens 1]

I think my rural king sells those tips. Also, Larry zoeller has a burner that the damper hole is at a 45 instead of a 90, same affect or is one better?

[C.Anderson 13]

45 is better. Harder to find by a mile. I went to my local industrial plumbing supply and they hadn't even heard of them. I've found them here though. At the other places I've found them in the past they were all on back order once put in the cart however...so I never bothered to pursue it.

[Wes Detrick 482]

Pretty much, yep! The flare is built into the forge lining though...so it won't wear out . I've still got to learn to tune the things...but they definitely get hot, that's for sure.

 

What mig tips/orifice are you using, out of curiosity?

 

I believe they are .045 contact tips. I didn't build my burners; but they were built by a friend from the design over at Zoeller forge for his sidearms.

[Dustin Stephens 1]

Thanks Cris for all your help, I will look into some places around here and if I find any cheap, I'll let you know

[Jerrod Miller 333]

In addition, they come in packages of 5 for $12 lol. I'm running .036" now....but I'm curious what all you guys are running.

I have 0.030" in mine at the moment. I've been thinking about dropping down to 0.024" and bumping up the pressure. The intended effect would be to inject the same amount of propane into the forge, but have it moving faster and thus pulling more air with it, improving my efficiency.

[C.Anderson 13]

I wonder how well that will work Jerrod. The concept seems there, but the most efficient forges I know of work at lower pressures lol...so I would have to think it through.

[Joshua States 1,220]

If I can jump in here for a moment, this discussion is venturing into the limiting factors associated with the venturi style burner, namely fuel efficiency and setting air/fuel mixture ratios.

Fuel efficiency should not be measured in terms of what pressure you are running at, but what heat output you get for the volume of fuel you are using. While this can be very difficult to determine exactly without expensive temperature measuring equipment, I can offer a simple method for determining the heat output at a specific fuel consumption rate (psi at the regulator), and a simple method for adjusting the air/fuel mixture on the type of burner Chris has.

 

First: The heat of the flame. Typically the hotter a flame is, the more toward the blue/white end of the color spectrum it appears. The flame in Chris's video appears pretty much in the orange/yellow range, so it is probably not getting as hot as it could be considering the pressure he is running (5 psi) and the size of the burner he uses. What I like about my NC Tools forge is that the flames come out of the burners blue/white and the forge heats up very quickly. One item of note: The air intake ports on my NC Tools forge are quite small when compared to the air port on that 2" pipe elbow. (I can take a picture and post it later) So, the air fuel mix is quite different compared to what you get with an open 2" elbow.

 

Second: Adjusting the air/fuel mixture. You could tap a small hole in the lip of that air port and cut a 2" diameter disk to use as a partial cover (I have seen this done with great results). The disk is drilled to accept the screw and the disk is rotated to partially cover the air intake hole. Turn the forge on, set the working pressure, and adjust the air admittance until the flame reaches a blue/white color. You are then operating at the most efficient air/fuel mixture for that pressure. i.e. you are getting the most heat out of a specific fuel flow rate.

[Dustin Stephens 1]

Sounds good Josh, when i build mine, I do want a damper on my air intake so that should cover it pretty well. Im not real familiar with propane and setting the air/fuel ratio, but how you described it sounds pretty easy

[C.Anderson 13]

Quick corrections! It's a 1 1/4 x 1 x 1 1/4 tee, and I've made zero attempts to improve or tune anything yet . When I do my first moves will be a choke, and injection nozzle placement.

 

But...I do agree with you completely Joshua! Just no time right now to go into it completely. Please, carry on!

Edited January 27, 2016 by C.Anderson

[Jerrod Miller 333]

I drilled and tapped a hole like that that thinking I would need it, but I'm still trying to get MORE air, not less. I hope to eventually need to reduce my incoming air, because then I really can try to control it and be efficient. Right now I can play with my pressure and needle valve to get flow changes. I worry that my needle valve is a bit of an unknown restriction and the pipe between the valve and the MIG tip causes something other than what I think is going on based on my regulator setting. More playing needs to be done for sure, but I can weld and heat treat, so it is just a matter of fuel consumption for me.

[Joshua States 1,220]

Chris I apologise for not getting the size right on that tee fitting. Should have checked. You could do a quick trial choke and see if it improves the heat just by using a piece of duct tape to cover part of the intake hole.