Burner problem

D

DrThunder88

Joined
Apr 26, 2007
Messages
957
I'm getting set up to try forging, but my burner will not light or stay lit for more than a few seconds. The design is based on a few different plans found online. It's built out of mostly 1 1/2" black pipe and uses a ~100 CFM blower. The propane runs through a 0-15 PSI regulator and traverses a brass needle valve prior to entering the burner itself.



I can light the propane when the blower is off, resulting in a billowy orange "eternal flame"-style flame. As soon as I turn the air on, even with the intake of the blower closed off, the flame sputters and dies.

Admittedly, I haven't run the propane at any pressures higher than 10 psi for fear of freezing up the propane tank in the last couple days' 15 degree weather. Is insufficient pressure the likely problem?
 
You may have too much air and not enough propane. How do you control the air flow? Is your blower a hand crank or electric motor driven? Whatever it is, try starting off with little air and then slowly add more air. It could also be that you're not letting your forge heat up enough before kicking in the blower. Try letting it warm up before you add more air.
 
The one thing I don't see is a control valve for the air, that will be necessary for this type of burner. I suggest a 1 1/2" gate valve, it what I use.
Thanks,
Del
 
My burner is very similar and I run it with the air almost closed off.

I turn the air on first, throw in a lit piece of paper then shoot the gas to it. Works fine.
 
Last edited:
Did you try lighting it in the forge or have you just tried lighting it outside the forge? The type burner you made needs to be in the forge for it to stay lit. A few ventura style burners will burn outside the forge.
 
Thank you for the responses. I did try running it in the forge yesterday, and it did provide the longest burn time, but it was sputtering heavily and died when I nudged the air control open slightly.

The air control (not shown) is a sliding plate over the squirrel cage blower intake. I had a ball valve to use, but I would have had to increase the height of the burner and, consequently, the forge to fit it in.
 
DrThunder88 said:
Thank you for the responses. I did try running it in the forge yesterday, and it did provide the longest burn time, but it was sputtering heavily and died when I nudged the air control open slightly.

The air control (not shown) is a sliding plate over the squirrel cage blower intake. I had a ball valve to use, but I would have had to increase the height of the burner and, consequently, the forge to fit it in.
Click to expand...

Sounds like to much air if it went out after you gave it more air. Just try cracking the baffle when you try starting it and then adjust after its had a chance to warm up some. If you were running at 10 pounds pressure that is a lot higher than it needs to be also.
 
A baffle plate on a blower isn't going to be enough to limit the airflow. You have too much air going through the burner (and a whole bunch of gas as well!).

You'll need a gate valve to really control it. As with Don's setup, my forge runs like a rocket with the gate valve almost entirely closed and with very little gas (running about 1 psi). The amount of air I needed when I first get the forge dialed in was much, much less than I thought it would have been.

--nathan
 
Last edited:
DrThunder88 said:
Thank you for the responses. I did try running it in the forge yesterday, and it did provide the longest burn time, but it was sputtering heavily and died when I nudged the air control open slightly.

The air control (not shown) is a sliding plate over the squirrel cage blower intake. I had a ball valve to use, but I would have had to increase the height of the burner and, consequently, the forge to fit it in.
Click to expand...

Just how big is your forge? What shape is the combustion chamber? (a picture is worth a thousand words) Remember, at 100 cfm, thats roughly 1.7 cfs. The combustion chamber on my forge is only .5 cubic feet. I can't imagine your forge being more than 1 cubic ft. in volume. See if you can't wire in a dimmer switch to your blower. (I'm assuming its electric.) If that doesn't work, then you will either need a bigger forge, or a smaller blower.

Quick question. What is the ideal air/fuel mix with a propane forge?
 
bladsmth said:
69,
There is no jet on a blown burner.
Stacy
Click to expand...

Thought I'd ask cause he said the design was based off of several designs on the web, and when I converted my venturi burner to blown I didn't change anything with the jetting. If it did I would have suggested that it might be too small or plugged with some shmegma or maybe the needle valve isn't working like it should be.
 
Sometimes that Teflon tape (which I have read is not a good idea with propane because it interacts and produces nasty toxic fumes) dangles down inside the pipe and impedes the flow. Friend and I built a couple of these and had terrible trouble as you describe until we cleared the goop out. Speaking of fumes, be SURE to use the forge with plenty of ventilation!!
 
I've never seen any sources talking about toxic fumes from teflon and propane. In fact, it's always recommended in the use of pipe threads transporting natural gas or propane. There ARE different grades of teflon tape, and the double thickness (yellow) teflon tape is recommended for gas installations. Be aware to always wrap the tape in the same direction of the tightening of the threads, and never use teflon in flare or other precision fittings. If you use white teflon, use 3-4 complete wraps.

--nathan
 
I hadn't considered that my forge may be too small for the burner. It is a roughly tubular 6 inch by 9 inch chamber.

If need be, I'll look at rebuilding the burner to fit a valve after the blower. That was my original intention, but the ball valves I found would not fit with the way the cart is assembled.

I have heard of Teflon coating on cookware degrading and emitting toxic vapors if heated up too high, so I tried to keep it as far behind the nozzle as possible and only on the joints that had to remain somewhat mobile.

Thanks again. Lots of stuff to think about.
 
Just put an elbow on the air pipe, and mount the valve and blower 90 degrees to the direction it is now. That will give you all the room you want.
Stacy
 
You say you used various designs found on the net for this burner. Can you please tell which ones and where they are found. I cant seem to find anything like what you have here. Perhaps if we knew the original design could be of more help.
 
my burner is almost exactly the same as yours. If I were you I would unscrew everthing from the t on the burner side and replace it all with the black iron nipple at the bottom of you photo. then either make a flame holder of some sort and you should be good to go. But your burner is at least three times too big for the size of forge I am envisioning that you have. my burner this size is in a forge that has a 22 inch diameter by 24 inch deep verticle forge and I run it with the air nearly closed.
 
You must log in or register to reply here.
Back
Top