Forge and foundry build

[Tom O]

I have seen some made with chains hanging down over the openings to stop the heat loss.

 

[Chris Cramer]

Here are some pictures of the forge with the burner running at 3 - 5 psi, and the air choke tuned to give a none oxidizing flame. It only reaches 1100 degrees at this preasure as it is delivering 100,000 btu/h, I cant seem to get the forge up to forge welding temperature. When I turn up the preasure it barely increases the heat - according to my thermal couple, and just pushes the dragons breath which looks like a sign that heat is only getting pushed out and not being gathered in the forge. It may be because my burner is over sized, but with it running that low should it still be producing such a big flame?

 

[Bofobo]

Try low air pressure into the burner, once its hot enough, what size pipe did you use?

 

[Chris Cramer]

I didn't build this burner, this is a DFM atmospheric burner from devil forge. It's actualy meant for larger forges, but the smaller burner I purchased from them (the dfp) didn't seem hot enough.

 

[Bofobo]

It looks as though the gas is unable to combust in the forge, once it finds enough air outside the combustion chamber (dragons breath) it burns freely but the heat is not maintained inside the forge, when i wanted to melt more than aluminum with a regular propane torch i needed to add compressed air to bring the combustion back into the foundry, it got hot enough to melt the copper and steel crucibel into an inseparable mess, mind you that was 2, 1lb bottles with torch tips and compressed air but you should be able to do the same.

 

[Chris Cramer]

Would adding a blower to the forge body cause oxidation to the the metal being heated if the air blown into the forge doesn't instantly mix with the fuel and combust in the forge, or would I have to convert the burner to a air forced burner by removing the air choke and adding a blower to the back?

 

[Bofobo]

very little pressure is required, could be made to do both? just keep a venturi effect in mind by adding an angle to the incoming air pipe

 

[Chris Cramer]

What would happen if I added the blower to the forge to blow air into the burning chamber would it provide enough oxygen to allow the fuel to combust as soon as it leaves the burner nozel? The gas is supposed to mix with the oxygen inside the burner, but the size of the exhaust on the back side as well as the size of the front opening put together probably isnt enough to allow the gas to flow smoothly and suck in enough oxygen through the vacume effect caused by the high pressure gas.

 

[Chris Cramer]

Thanks for the help, today I tryed using a blower on my burner and it turned out to provide enough oxygen to allow all the gas from the burner to combust in the forge as a neutral flame without any dragons breath. Now I just need to find a way to mount the blower to the back of the burner or in a position close to the back of the burner without being melted by the heat, or find a blower that is metal.

 

[Bofobo]

The blower "should" provide enough of its own cooling power, i used an old hair dryer on my first coal forge and never had a problem with heat transfer thru the not insulated semi truck brake drum and 2" pipe less than 12" from the fire. Mind you the dryer was old enough to be made of bakelite. Glad it worked out