forge problem

CWendling

CWendling

Knifemaker / Craftsman / Service Provider
Joined
Sep 10, 2005
Messages
528
So I still havent figured out why my forge wont run smooth and was hoping someone could help. It is a darren ellis 4" forge. It sputters, like its going out and relighting. I have run it off three tanks, a 100lb and 2 bbq tanks and get the same issue, so i dont think its the tank. He replaced the regulator once, so i dont think it is the regulator. ive messed with the settings, turning gas from 5-8psi or so and adjusting the gate valve at the forge, with no seeming change. Someone before had said the tip might need to be adjusted? If so, is that this piece inside? how would i adjust it? It seems prettywell locked in place. looking in the forge i have a bit of blue flame coming from the end of the gas pipe into the forge, and then a nice reddish swirl. It will get to about 17-1800 in a few minutes, and thats when it really starts to sputter.
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If you're making it to 1700-1800F, you're pas the critical point where the forge should be self igniting, so we can rule out "too cold".

If you could answera few questions it will be easier to help you figure it out:

  • Is it a forced air or atmospheric burner?
  • When you have it running, What does the flame exiting the mouth of the forge look like? Is it blue, or orange?
  • About how far out from the forge mouth is the flame projecting?
  • What does the forge sound like prior to the sputtering?

-d
 
1.it is not forced air.
2.im in the sunlight when running it, so i dont see any flame out the front, but can see the heat wave. the rear of the forge is blocked with a firebrick
3.like i said, dont really see flame out the front
4.it sounds like a jet engine i guess

should i be running higher than 5psi or so off of the propane tank?
 
It seems like it cant get enough air into. I had the same problem with my venturi forge, I modified to a forced air and the problem solved. But as it is a well known forge, it may be because of something about your valve or there is a production fault... Maybe it is best to discuss it with the producer..
 
CWendling said:
1.it is not forced air.
2.im in the sunlight when running it, so i dont see any flame out the front, but can see the heat wave. the rear of the forge is blocked with a firebrick
3.like i said, dont really see flame out the front
4.it sounds like a jet engine i guess

should i be running higher than 5psi or so off of the propane tank?
Click to expand...

My experience is mostly with forced air setups, but I can tell you that you should be seeing some flame out the front of the forge when it's running right. What this indicates is that you have a bit of fuel left unburned because it ran out of oxygen inside the forge for combustion. This ensures you have a reducing atmosphere, which will reduce scaling as you work. I'd up the pressure a bit until you get 2-3" of "dragon's breath" exiting the front of the forge. Try at dusk if you're having trouble seeing it until you get the feel for it. My guess is that you do not have enough gas going once you get to heat which is causing your sputtering. Once the forge is hot, your fuel combusts more rapidly inside the forge. If you are burning all of your fuel and have excess air, your flame will "go out" before more fuel makes it out into the burner, hence the sputtering.

Once it start pulsing/sputtering, try upping the pressure slightly a bit at a time and see if it settles out.

-d
 
1. Loosen nut #1 from Nut #2. That will allow you to move pipe nipple #3 in or out. The mig tip should be centered in the opening, but you may have to move it farther up the burner tube.
2. The burner tube should be about 1/2" back from the chamber opening.
3. turn the gas down even more.
 

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You can also test it outside the forge to see what the flame is doing just clamp it in a vise or somehow hold it and then move the mig tip in and out until you get a nice looking flame you may also need to adjust the flare at the end of the burner but basically you should get a flame that is right at the end of the burner without moving past the end of the tube once you get it dialed in you it really doesn't need any adjustment and should run from next to no pressure on up. Check http://www.zoellerforge.com/faq.html for more info on turning.

I have one of Darrens burners and it will easily run my 7" vertical forge at 2000+ at 3 or 4 psi I added a damper on the air input for more control of the type of flame.
 
On venturi burners ( atmospheric) there are several things that cause problems that are sometimes hard to figure out.
One is too low pressure, another is too high pressure. Too low and the flame wants to climb back in the burner tube, causing sputtering and squealing.
Too high and it blows out, then reignites, causing sputtering and popping.

Also, if the burner tube ,or the flare, sticks out in the chamber, it heats up. Once it gets hot enough, the flame wants to ignite too soon, and tries to burn back in the tube, where the heat ignites it.

Placement of the jet tube is critical, and must be set at the forge site. Even if it was set at the factory, differences in equipment,altitude, and other things can change how the venturi draws air.

Some solutions to all these are:

1)Make sure the orifice is clear and the proper size. It should be pointing straight down the center of the burner.
2)Make sure the jet tube (with the orifice on the end) is placed in the exact spot to create the venturi.
3)Make sure the forge has enough exhaust porting to allow the chamber pressure to stay low enough to prevent back pressure in the burner tube.Too high a chamber pressure will cause collapse of the venturi, causing sputtering or flame-out. With the forge running at full blast, and up to high heat, there is a lot of hot expanded gas trying to get out the ports. Most forges are designed to have big enough openings. Block one up and you cut the exhaust porting in half. (Try putting a 1" tail pipe on your V-8 and see how it runs.)
4)Make sure the burner flare or burner tube is not projecting into the chamber. The flare should be about 1/2 to 3/4" back, smoothly bedded in a cone of refractory. The burner tube should be placed so it is just at the start of the flare, or slightly back from that point.
5)Raise or lower the pressure and observe the changes.
6) As pointed out, adding a damper plate to the air port can make fine tuning easier.
7) Change to a blown burner and eliminate most of these problems.

Stacy
 
If that's an Ellis burner, it should be complete with all the right parts and it shouldn't be too tough to run well. If you haven't tried, I'd consider taking the gas tube out and make sure there's no debris or sealing tape getting in the way or in the mig tip.

I'd also guess the forge is set up right. If you want to run it at 5 psi, a choke on the air intake like others mentioned could be a good idea.

Best of luck, Craig
 
Thanks for all the suggestions. I think I still have some tuning to go, but its running much better. I didnt change anything on the mig tip, but I did move the burner in closer to the chamber and i removed a bit of refractory that was a little bit over the opening into the chamber. No more sputtering at all. Its hovering around 1900 with the psi at 10 and the gate valve almost all the way open. About 4-6" of blue flame out the front. So Im thinking move the burner a little farther in? Does that sound right?
 
Cory,

Don't get the flare inside the forge or you'll burn it out pretty quickly the opening should be clear and the end of the flare should be just past the forge body inside the insulation but not past it. I think that the burner is intended to run with the gate/ball valve all the way open and use the pressure to control the temp. If I ran mine at 10 psi it would be way above 1900. Try tuning it with the ball valve full open and reduce the psi start at 5 and see how it goes.

Tim
 
Ok. Im still farther back than that with the end of the flare. The instructions said 1/2" back, so right now its about 1/2" or so back of the forge body, before the insulation. It seems when i originally assembled it, I measured wrong apparantly and was about an 2" back of the forge body before. Which I guess is what was making it sputter. Ill move it closer to the insulation tomorrow and see what happens
 
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