Forge welding in a propane forge

[caver95]

I am trying to make a forge weld in my propane forge, I can do it on a small area for a fire proker, but I tried to make a basket for a handle, and I could not get it. I finally heated it up with a torch and did it. Is my forge not hot enough, did I not do it right? I am using borax for flux. Any advise is welcome.
Nick

[Woody]

From what you have said it is difficult to make an assumption but my guess is it just didn't get hot enough. This is information that I got from the Anvilfire Guru Den several years ago.

"You will need at least 450 BTUs per cubic inch of forge chamber volume if your forge is going to be able to forge-weld. Some would argue for a figure as high as 540 BTUs per cubic inch.

The "Reil Burner" will deliver about 135,000 BTUs at medium to higher gas pressures, and can be cranked up to almost 200,000 BTUs by raising the pressure to 20 psi or more. In the lower pressure range of from 1-6 psi, where I do most of my work, it will produce about 60,000 BTUs, or even a little less. Use the middle figure in any design calculations.

Shoot for a burner to volume ratio of 1:300 or less. Some smiths who are very
knowledgeable would say a more conservative ratio of 1:250 would be safer and insure that your forge will be able to weld. To calculate how many 3/4" burners you will need just divide the total chamber volume of your forge, in cubic inches, by 250 or 300, and then round up. If you come out to a burner requirement of 2-1/3 burners, then you will need 3 burners for your planned forge volume. Always plan conservatively or you may end up with a forge that is too cold to forge-weld."

[ThomasPowers]

Not hot enough or too oxidizing or both. Can you tell me if I am holding this hammer the right way?

[caver95]

Originally Posted by ThomasPowers

Can you tell me if I am holding this hammer the right way?

Yes, you are not.

[caver95]

Originally Posted by Woody

From what you have said it is difficult to make an assumption but my guess is it just didn't get hot enough. This is information that I got from the Anvilfire Guru Den several years ago.

"You will need at least 450 BTUs per cubic inch of forge chamber volume if your forge is going to be able to forge-weld. Some would argue for a figure as high as 540 BTUs per cubic inch.

The "Reil Burner" will deliver about 135,000 BTUs at medium to higher gas pressures, and can be cranked up to almost 200,000 BTUs by raising the pressure to 20 psi or more. In the lower pressure range of from 1-6 psi, where I do most of my work, it will produce about 60,000 BTUs, or even a little less. Use the middle figure in any design calculations.

Shoot for a burner to volume ratio of 1:300 or less. Some smiths who are very
knowledgeable would say a more conservative ratio of 1:250 would be safer and insure that your forge will be able to weld. To calculate how many 3/4" burners you will need just divide the total chamber volume of your forge, in cubic inches, by 250 or 300, and then round up. If you come out to a burner requirement of 2-1/3 burners, then you will need 3 burners for your planned forge volume. Always plan conservatively or you may end up with a forge that is too cold to forge-weld."

I will try putting a couple brinks in the chamber take up some space.

[looper567]

What is your forge insulated with?

[caver95]

Originally Posted by looper567

What is your forge insulated with?

2" of kaowool

I did a little math and I have to much volume and not enough burners. So I am thinking I will make another burner and redo the forge with castable refractory.

[ThomasPowers]

Castable refractory will eat up a lot of heat but be more resistant to flux. You may have to preheat the forge longer before welding.