Small compact Propane Forge - How HOT will it get?

[Zeppe807]

I have made a box, and I am planning to make a torch tonight from this site:
http://ronreil.abana.org/burner.gif
http://www.popsci.com/diy/article/2009-11/build-your-own-propane-forge
But I am worried the torch will be too big, use too much gas, or not get hot enough to forge weld railroad spikes.

Will I be happy with using this over my charcoal forge?

The small torch was there for effect.

Thanks,

 

[Smitty3215]

I forge weld in a gas forge daily. the only thing is the flux will eat the liner alive.

 

[Zeppe807]

I forge weld in a gas forge daily. the only thing is the flux will eat the liner alive.

I didn't think about that. is there a solution to that? My main concern is that I can get it hot enough quick enough to get things done. I don't forge weld much. It is mainly going to be used to shape knives, and other small projects, considering the size.

I appreciate the experience. Thanks.




Joe

 

[Zeppe807]

Well, I made a new torch for the forge, but 2 things:
1) I should have gotten black pipe, not galvanized.
2) I don't think the regulator that I have flows enough.

It does not produce a flame like a torch, and I am also wondering if I make it out of smaller diameter pipe, would it produce a better flame. (?)

Anyways, I think I am going back to my old forge to finish my current project, and while I look for more info.



Joe Zeppe

 

[Sureshot]

I have never built a forge but I am interested in building one. Used one many years ago.

If I were you I would get rid of the regulator. Use a needle valve or if still not enough a small ball valve to control the flow. That is all a tiger torch uses and we used to make some tiger torches with needle valves before the safety cops said they had to be factory and now they are pretty much banned completely.

 

[kazlx]

This might help

http://www.docsmachine.com/projects/forge/fg01.html

 

[zkling]

Hi Zeppe807,

I have been doing bladesmithing for the past ~8 years. Trying to remain frugal and space conscious I have went through multiple different forge designs.

I have settled on two different types of forges for general forging work. Each based on what your intended goal is.

My high temp forge is based upon a Don Fogg vertical style forge. The vertical forge is great for welding as the flux and junk falls to the bottom of the forge. This is powered by an old residential oil burner, converted to burn WVO and kero to save on propane costs. This has kao wool insulation with a top coat of hard refractory to prevent the flux from eating away at the insulation.

My second forge is more of a traditional horizontal forge such as yours. However I much prefer a blown style of propane burner. It is an old oxygen cylinder lined with Kao - wool insulation.

With your venturi style burner, you will need a "high pressure" propane regulator that will allow adjustments form 0-~25psi. In your picture it looks like you have a BBQ style regulator, most of which are regulated in W.C. and translate to ~1psi max.

I prefer the blown style burner as it is much more efficient, especially when using smaller 20lb propane bottles. The smaller BBQ bottles can actually freeze up with a venturi style burner when turned up to welding temps.

You also may want to consider a insulation blanket such as Kao wool or the like on the outside of your firebrick. Firebrick by itself is not to good of an insulator.

Here is a link to a really great bladesmithing site. VERY knowledgeable / friendly / talented people over there.

http://forums.dfoggknives.com/

As well as a good tutorial on vertical forge building with a blown burner.

http://www.dfoggknives.com/forge.htm

As for why your burner does not seem to be very "torch like". You really need to verify the pressure going into the burner. Also what diameter is your orifice? I suspect you have a lack of pressure going in, or too large of an orifice.

Welcome to the great hobby of knife making. Warning... your friends / neighbors may begin to think you are crazy.

 

[kindyr]

First question: are those firebricks the hard kind or the soft kind? based on my Limited) knowledge on the subject, the hard kind are typically structural, and designed simply to handle the heat, while the soft kind are refractory in nature, reflectinging and better keeping the heat in the forge. For a forge like this, I beleive the recommendation is to use the soft, possible with a peice of hard firebrick on the bottom where you would chew up soft brick pulling the steel in and out.

Second question: is that a regulator for the small can's of propane? It looks a lot like the one I had on a small camp stove. For a burner like that, you'd need at least one for the 25# or larger propane tanks, and preferably a High flow regulator like on Large BTU propane grills or boiling pots.

 

[Zeppe807]

Hi Zeppe807,

I have been doing bladesmithing for the past ~8 years. Trying to remain frugal and space conscious I have went through multiple different forge designs.

I have settled on two different types of forges for general forging work. Each based on what your intended goal is.

My high temp forge is based upon a Don Fogg vertical style forge. The vertical forge is great for welding as the flux and junk falls to the bottom of the forge. This is powered by an old residential oil burner, converted to burn WVO and kero to save on propane costs. This has kao wool insulation with a top coat of hard refractory to prevent the flux from eating away at the insulation.

My second forge is more of a traditional horizontal forge such as yours. However I much prefer a blown style of propane burner. It is an old oxygen cylinder lined with Kao - wool insulation.

With your venturi style burner, you will need a "high pressure" propane regulator that will allow adjustments form 0-~25psi. In your picture it looks like you have a BBQ style regulator, most of which are regulated in W.C. and translate to ~1psi max.
Yeah the regulator is off a BBQ, I had it lying around, I thought I had a regulator off an old cabover camper, but I couldn't find it. What is the easiest way to plumb the lp tank to a hose, is there an adapter from the tank threads to a npt?
I prefer the blown style burner as it is much more efficient, especially when using smaller 20lb propane bottles.I will have to look it up. The smaller BBQ bottles can actually freeze up with a venturi style burner when turned up to welding temps.

You also may want to consider a insulation blanket such as Kao wool or the like on the outside of your firebrick. Firebrick by itself is not to good of an insulator.

Here is a link to a really great bladesmithing site. VERY knowledgeable / friendly / talented people over there.

http://forums.dfoggknives.com/

As well as a good tutorial on vertical forge building with a blown burner.

http://www.dfoggknives.com/forge.htm
I feel like I am registered to too many addicting sites already, please don't tempt me
As for why your burner does not seem to be very "torch like". You really need to verify the pressure going into the burner. Also what diameter is your orifice? I drilled it out with a jet drill set to .04". I made it to the specs set out in the link above. I am sure that I am not getting the pressure needed. I suspect you have a lack of pressure going in, or too large of an orifice.

Welcome to the great hobby of knife making. Warning... your friends / neighbors may begin to think you are crazy. They already do!

I have been making a few here and there. I lost the chance to make my "next knife" for my Uncle before he passed away, and it has been bothering me a lot. I want to make some more for those around me. Each one has been different, and fitting for the person getting it. They are no masterpiece, but a nice unique knife that will last forever.

I am trying to get a couple done for Christmas, and will probably resort to my old blown charcoal forge. But I will have to wait till this weekend to go get it, it is not at my new house yet.

All the help and info is great, I will have to do some more research.



Thanks,
Joe Zeppe

 

[Zeppe807]

First question: are those firebricks the hard kind or the soft kind? based on my Limited) knowledge on the subject, the hard kind are typically structural, and designed simply to handle the heat, while the soft kind are refractory in nature, reflectinging and better keeping the heat in the forge. For a forge like this, I beleive the recommendation is to use the soft, possible with a peice of hard firebrick on the bottom where you would chew up soft brick pulling the steel in and out. Softer, and the higher temp bricks at the stove store...

Second question: is that a regulator for the small can's of propane?yes It looks a lot like the one I had on a small camp stove. For a burner like that, you'd need at least one for the 25# or larger propane tanks, and preferably a High flow regulator like on Large BTU propane grills or boiling pots.

I will have to look for a bigger regulator.



Thanks,
Joe Zeppe

 

[Amitygravel]

Joe ,
I'll try to describe my friends forge the best I can. Unfortunately I don't have any photos of it in my phone , might be there this Saturday and will get pics and post them up.
His current set up is single burner , fire brick base (yes flux eats it up , that's just the way it is ). The rest is made of Kao-wool blanket and board.
The regulator is an exatylene unit even though he uses propane.
This setup is also forced air using a small blower that he usually gets from Grainger.
Black iron pipe is used for the burner and I believe its either 1 1/2 or 2 inch diameter.

Kao-wool is awesome stuff. Really does the trick for containing heat.
Using your new forge and lining or even wrapping it will make a big difference.
Enough so that a two or three propane torches would get you up to a working temp though you may have to bring your interior dimensions down.

Here's a shot of a recent batch.

 

[zkling]

Here is the kind of regulator you are going to need for the venturi style burner.

http://www.hightemptools.com/propaneregulators.html

Back when I started lots of guys used regulators from some cajun restaurant supply house.

Also that site is good to snoop around on and look for ideas in terms of forge design.

You can also get the regulators at a welding supply house, just take note of the threads. Most of the large propane tanks are internally threaded and don't have an OPD like the standard 20lbers. Any quality regulator in the 0-30psi range will work. Get one that has a pressure gauge readout, it is so much easier to reset. And for safety sake always check connects with liquid soap. I have always been really hesitant about flammable gas and leaky connections.

Have fun.

 

[theknurl]

you need more propane?

use a larger flow acetylene regulator....like a 'd' series Victor

be aware you may have to manifold tanks together at really high flows

i made a 70-80 gallon crawdad cooker......the flow rate was so high it would freeze the tank.....8, 1/8" orifaces@15PSI

but it would be at a roiling boil in 25 minutes

 

[Zeppe807]

you need more propane?

use a larger flow acetylene regulator....like a 'd' series Victor

be aware you may have to manifold tanks together at really high flows

i made a 70-80 gallon crawdad cooker......the flow rate was so high it would freeze the tank.....8, 1/8" orifaces@15PSI

but it would be at a roiling boil in 25 minutes

I was just thinking about an old CO2 (or was it Oxygen?) regulator. I was thinking the flow rate would be much better, but would the propane be Okay through the regulator?

I will have to chase it down and then get an adaptor for the propane tank.



Joe Zeppe