Forced Air Burner Tuning- Help

[gables]

A recent car repair wiped out all of my fun money and some savings but I decided selling my canoe was worth the cost of burner parts and rebuilding some savings. I am, however, having tuning issues.

Here is the synopsis of my brief experiments. I have the regulator at 8-9 psi. I have a needle valve for gas control and a gate valve for air control. Too much flame gives me a log yellow flame. Too much air blows out the flame. Can't seem to find a happy medium. Below is video link. At the end of the video it seems to burn well but then blows out.

  Burner

[kbaknife]

I regulate my gas at only 4 pounds.
That's to give me welding heat for damascus, and when I'm doing some heat treating and/or forging smaller blades, I only run about 3 1/2#s.
Then tune it from there with the needle valve and gate valve.

What's the CFM on your blower?

[Scott Roush]

hey... i guess that saves you replying to me email. Thanks Karl....

[gables]

My blower is rated 56cfm but I have it choked down with the gate valve. Thanks for the input. I'll adjust regulator and open up the needle valve some more.

[Scott Roush]

Mine is 75 Karl.  And... You have the gate valve for adjusting the atmosphere... Mine has a couple of holes I can use to put a choke plate. Do you see any advantage to having a gate valve?

sorry for jumping in here but I was working on my forge just as this thread started!

[kbaknife]

Mine is 70CFM, Scott, on my large forge and I think 50 on the small one.
I only use the gate valve on one of my forges because the blower body won't accommodate an intake flap.
That gate valve is not only for adjusting atmosphere, but temperature as well, for when the gas pressure is lowered/raised.
I just find that fine balance between having a little flame coming out the door, and NOT! having the combustion try to work BACKWARDS into the blower body.
And this needs to be adjusted as you raise and/or lower the line pressure.
(These have since been re-configured to suit my new pedestal arrangement)


Gate valve:

   


No gate valve:
(This one has the adjustable intake flap on the blower on the side away from us here.)

   

   

[Scott Roush]

Thanks Karl...

well I just fired it up. Now I see why folks recommend eye protection. Man it gets bright in there. I will now be adding some UV protection when I'm running it like that for when I finally start forge welding. But man this is nice... a lot easier to control the heat.

Just realized something though. I didn't cut in a rear exit for working with longer stock!!! Back to grinding...

[Scott Roush]

Karl.... I see that you have some kind of square tubing welded on to your rear exit.  Do you keep that shut most of the time?  I'm just wondering about how to handle mine and about getting even heats for heat treating,etc....

Right now I have just have a smaller rectangular hole ground out to stick the tip through...

[kbaknife]

Scott, I'm not even sure if it really works - but I have no indication to the contrary, either.
I consider that square tubing an "extension" of the forge body.
When welding up and drawing out damascus billets, I pass the bar through the main body and into that tube, and I feel it retains some of its acquired heat a little longer, rather than cooling off by sticking out into the room air on the other side, if it was simply an un-obstructed opening.
I have a bolted door on the end of the tubing if the bar becomes too long and must be passed on through, but I keep it closed nearly all of the time.
I also have a feeling I can use less fuel and keep the forge hotter if I'm not losing heat out the back door.
So, I have one on each forge.
We hear lots of things in the knife making world, and once I heard an explanation of a process that I might use here, "It won't hurt anything, and it might help!".