Venturi burner tuning for my forge?

Robert Hankins

Robert Hankins

Joined
May 19, 2003
Messages
1,848
Don't get over here as much as I used too. But I finally got off my butt and got my forge going --- Well sort of:rolleyes:
Followed the Riel mongo burner instructions 3/4" pipe with 1 1/2" bell attached. Am using a Freon tank turned sideways with the top and bottom cut out.
Here are my initial questions:
How big should my openings be on either end?
Is it normal for the flame to start about 3/4" from where the gas jet is?
Fired up just fine but did not get very hot.
Does the flame have to be pointed directly at the steel?
Tilted mine at about a 45deg so it hits about 2/3rds of the way toward the bottom.
I am using a 0-15 lb regulator along with a normal regulator used for a gas BBQ.
Does not seem to have enough pressure as I expected the flame to be roaring, it was rather tame.
Should the complete flame be blue?
Mine has yellow at the base.
Will get pics in a few.
Thanks for your help guys!
 
Robert, First thing I'd do is chuck that BBQ regulator.
They are designed to operate on low pressure and you need
high pressure at the forge. The other regulator should work
ok by itself. Are you using some kind of orface inside the burner
and if so what size is it.If your using a mig welding tip thats
smaller that .035 then you might need a higher pressure regulator.
The burner should sound like a small jet engine if everything is
right. You won't need to point the flame at the steel if the burner is working ok.
As far as the size of the opening it kind of depends on what your forging.I wouldn't want anything smaller that a 4" square opening in mine. If you use a smaller opening then the flame tends to shoot straight out that hole towards the operator. A larger hole defuses the flame so it just kind of comes out and up. I think your biggest problem is with low gas pressure.
 
Pics
Sitting atop of an old BBQ pretty handy that way and portable.
forge.jpg

forgeburner.jpg

forgehit.jpg

forgereg.jpg

forgeregulator.jpg

forgeside.jpg


OK Please help me get this right!
 
Hey Robert, I second what Ron said, that regulator you have hooked directly to the tank is the problem. Remove that BBQ regulator and couple that hose directly to the propane tank...your other regulator is sufficient.

:)

-Darren
 
Looks like you need to put a flair on the end of that burner, your lucky it burns at all. If you take it out of the forge it probably won't. The flair makes it breath right, for some reason the flar gives you a vacuum effect so that it draw air through.

Here's an easy solution.

http://www.bladeforums.com/forums/showthread.php?s=&threadid=278592&highlight=Reil+Burner

Fix yourself up with something similar and see what happens. All you need is to work on the end of the burner, probably have enough stuff in your junk drawer to do it.
 
Hi,
Looks like one of my rigs. Deep six the BBQ regulator. That adjustable "fish Fryer" regulator will work splendidly.
The flare at the end serves as a flameholder. Keeps the fire positioned so it burns the gas completely and doesn't dance around.
Jay mentioned at the Reil site sells stainless steel flares that work very well. ALTERNATIVE: You can form your own flame holder IN THE INSULATION. Insert burner until tip is just inside the steel shell. At that point just use heavy application of satinite and mold the damp insulation to a very mild cone shape. 12 degrees of slope is standard. Advantage: Free Disadvantage:Burner runs like crap off of the forge.
As to burner alignment, I like to have the burner angled at a near tangent to the cavity. Others like a hot spot.
Many users of these things weld little tracks and make sliding doors for maximum heat.
Try blocking or put a sliding collar on the tube body of burner. That design works pretty well without any holes there at all.
You can regulate the air on the burner by placing a business card over the opening. Suction will keep it in place.
I ised a 2 1/2" bell on mine and used a lathe to chase out the threads to make the flow a litte smoother. Sounds like a rocket.
Enjoy, Ken
PS: I am still using that wood I got from your old garabe cleaning days.
 
your burner looks to have the same proportions that mine does. My 3/4 inch pipe is 8 inches long. I started out with a flare, but now that is long gone. From what I understand the flare is there to slow down the gas flow and act as a flame holder. The velocity of the gas shooting down the burner sucks in the air that it needs to burn, same principle as a carburator on a car.

My burner will not stay lite outside the forge. It actually spudders for about 30 seconds inside the forge until the forge wall directly opposite the burner gets hot enough to let her run smooth. I used a #59 drill bit for the jet. It is important to get the gas stream running straight down the center of the burner to get the hottest flame. If you used set screws to hold the tube in the flare, you can tune it while the burner is lit and in the forge.

Just light it up and move the tube in and out and rotate it. You will hear the difference. Now just position the tube until the noise is the loudest and tighten your set screws.

Also, i run my burner between 2 to 15 psi, bepending on what I am doing. On my new forge I can run at about 9 PSI and get to welding temps. I usually fire it up at 13 PSI and once it is warmed up cut back on the gas. On my old forge I had to run at 13PSI to get to welding temps.

Hope that helps, but i probably just repeated what everybody else said.:)
 
Well I think you definitely need to block off the openings some. I used compacted kaowool board to block off the back leaving a 3"x2" opening and the front opening is just like Ron's freon tank forge that he has the directions for on his web page, which is around 3.5"x4". You definitely need to get some satanite or better yet ITC-100 (or satanite coated with ITC-100) on that kaowool, it will improve it's performance markedly. One thing to keep in mind is that you can not block off the openings completely because a venturi type burner will not work. Many people I know just block off the opening with stacked fire bricks which allows you to adjust the opening sizes to whatever you wish. It might even work better if you reduce the inside dimensions by adding another layer of 1" kaowool (the picture is kind of hard to tell if you just have one layer of kaowool in there or two).

Using Ron's very basic EZ burner my freon tank mini-forge easily gets to welding temperature at around 6 to 10 psi and I generally forge at around 3 to 4 psi. I can even cut it down to as low as .5 psi for heat treating.
My EZ burner which doesn't even have a flared nozzle stays lit in open air as well. I think I drilled the orifice with a No. 58 drill if I remember right, but I built my burner before they thought to use the welding tips. The orifice is drilled in a 1/16" brass nipple that passes through the bell of the reducer.
 
This has been a great help so far Thanks all of you.
There is just one layer of Koa Wool I will add another one and coat it with Sanite and reduce the openings to your suggestions.
Report in a day or so.
I used a #57 drill for the jet drilled into the feed pipe.
Will add a flare if needed after I refire it.
 
Removing the BBQ reg helped greatly! Started to glow the Koa in just a few minutes.
Pics after I do my tweeks.
Hard to believe how relatively simple this is to make.
After I get more in tune with using this beast I have a 3' piece of 8" pipe that will turn into my Sword HT Forge:D
This will be so much fun to work with...
 
Blinker,
Lot of good advice here. Sounds like you got it pretty well sorted out. Ken mentioned the flare issue. You will find that you will get a more efficient burn for the PSI with a well adjusted flare on the business end of your torch. Although the flare will act somewhat as a flame arrester it's primary function is enhancing the vortex effect. Simplified: the restriction caused by your torch tube is releived at the flare accelerating the flow speed causing the torch to suck in more air on the intake side. This is what creates the blast torch effect. The speed through the tube is relative to your gas pressure being fed, the jet or orfice size it's fed through, and the amount of free air available at the intake. A well centered jet/orfice is also critical for best burn.
Always attempt to make everything as adjustable as possible so that fine tuning is easier.
Note: Only change one thing at a time! Check for results before
changing anything else.
I agree with the others that your chamber appears to be to large for one burner. You will need some way to adjust the size of your end openings to account for cross drafts and back pressure. Simple stuff really. A rounded soft fire brick plug will work well, sloppy fit is better for back pressure problems.
Have fun with it and play careful!
crex
 
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