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2:32 am
November 8, 2010
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I fired up my new forge today and while it did come up to temperature it seems like the burner was a little erratic. I tried adjusting the air/fuel mixture but could never seem to get it to come out of it. It's almost like it's stuttering.
My best guess is that the fuel isn't mixing as well as it should but that's just a guess. Anybody ever run into something like this?
Here is a quick diagram of what I am using.
Thanks!
Jim
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4:19 am
NWBA Member
April 19, 2010
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What kind of baffle do you have at the end where burner enters the forge? Can make a big difference. Blower is sure big enough.. Orifice size?
6:49 am
December 10, 2010
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I had a similar issue in the beginning. I changed the layout just a tad. Here is mine...
notice the gas pointing down the tube
[Image Can Not Be Found]
Keep on Forgin
The difference between stupidity and genius is that genius has its limits.
Albert Einstein
11:36 am
September 6, 2010
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JimB,
For these blown burners to work efficiently, you should be able to adjust not only the gas supply but also the air flow. From your diagram, there is no way to adjust the air. I’m guessing that your blower is blowing too much air for the amount of gas.
There is an easy way to check. Put a piece of steel in the forge. If scale is forming inside the forge then you have an oxidizing flame (too much air).
Something else to check is back pressure in the forge. Remember that the amount of air/gas you pump into the forge must have somewhere to go. If the opening in the forge is too small it creates back pressure in the burner.
2:15 pm
NWBA Member
April 19, 2010
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something you might also try that i found helped mix the air and gas is stainless steel "scrunchy" (pot scrubber) in the end going into the forge just enuf to stay without blowing out it does two things it mixes the gas and air and helps burn back in the burner ... i was able to reduce gas pressure and it increased the heat in the forge when i did this ..downside is it eventually burns out and if you put too much in it blocks down airflow...good luck!
2:35 pm
January 18, 2011
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Gas orifice size ????
"Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind."
— Dr. Seuss
3:49 pm
NWBA Member
August 7, 2010
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Good Morning,
If you add a gate or ball valve after the blower motor, you can control the air volume. I used a plastic gate valve on mine (because I had it) and it has worked fine for over 15 years. If there is heat back to the blower, you have burn back. Air is too slow/low. Electric blowers work best without a reostat (tried that, gate valve works more gooder).
The trick is to have enough gas pressure (small orifice = higher gas pressure, large orifice = low gas pressure), using an adjustable regulator (I prefer using one with a gauge so you can go back to known good), adjustable air pressure/volume. Adjust to the type of flame you want/need inside your firebox. Looking at the flame outside the fire-box proves nothing. Air/Gas that goes into the firebox MUST COME OUT SOMEWHERE!! It won't work if the doors are closed (read - chimney).
Large orifice means the volume of propane will be high. High propane draw means the propane tank will freeze. Joining 2 or 3 propane tanks together, in parallel, means the draw from each tank is less than with one tank. This means it will take a lot longer for the propane tanks to freeze. If you are using 20 lbs. propane tanks, sit them in tubs of water, water will act as a heat sink and allow you to use the forge for longer periods of time.
You must tinker, to get it working.
As long as we are above our shoes, We know where we are.:happy:
4:55 pm
November 8, 2010
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Sorry for the incomplete info guys I was wore out yesterday.
I have a slide gate right above the blower which can turn the air down to just a trickle when it's closed.
The gas is delivered through a threaded cap on the bottom of the T. I was told that it didn't need to be up into the T so I just threaded a brass fitting into the cap and the ball valve is below that.
I tried running it with the doors wide open and then with one side semi closed and finally with both sides semi closed. I used half a firebrick to block it with left an inch of opening on all for sides.
I have two tanks hooked up to a 140,000 BTU regulator @ 11" WC/0.5 PSI
Eric: Don't understand what you mean by baffle?
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6:13 pm
May 22, 2010
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I'm assuming here that you are using a Ribbon Burner with this setup? Which means you need as part of your setup, a chamber/baffle where the input tube (the gas and air mixture) that goes into the actual burner part. So you should have on the backside of your ribbon burner, a plate that either has a bunch of holes in it, or as Eric G stated, a nice wad of steel wool can accomplish this as well. This accomplishes mixing the air/fuel just before it is let out through the ribbon burner.
I'm not sure if you understand what I just said, I will look for a picture or drawing to help me convey what it is that everyone here is saying, =)
Brad Roland :hot:
6:17 pm
May 22, 2010
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I found a nice article by John Emmerling about Ribbon burners, this has the pictures I'm looking for, right on the first page it shows the parts you need for the ribbon burner ... take a look, it should help you put ...
Brad Roland :hot:
1:17 am
November 8, 2010
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I am familiar with the ribbon burners and plan on building one eventually, but for now I just want one of those oh-so-easy pipe burners that everybody's always talking about 😉
I came up with a few ideas to try tomorrow and I'll post something about my findings.
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3:39 am
August 2, 2010
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Jim, From your illustration it looks like you are trying to build a so called "zero pressure burner". I think you were given some erroneous information about where your gas line should end. Tomorrow try continuing the gas feed line up through the lower part of the T until it is at least into if not centered in the air path. You needn't bother trying to bend it over to match the air flow. You are basically building something like an old automobile carborator and the fast moving air from your blower passing over the open end of your gas supply pipe will draw a volume of fuel with it. Adjusting the air flow will cause the fuel volume to follow it. (Bernoullli/ Venturi) Resist the temptation to add a nozzle or mig tip or other orifice at the end of the pipe in this configuration. However you will want to raid your gas barbecue for it's low pressure regulator to control the gas flow. (Remember this is a forced air not an atmospheric burner and you do not require the energy of high pressure gas to entrain air. You are looking for volume not pressure here.) You do not want to inject gas at too high a pressure in this system but rather allow the volume of gas sucked out of the pipe to be regulated by the air flow. There is a much better explanation available on a process heating web site but I don't have a link handy. I think it may be burners 101 or heating 101, someone will surely chime in with it. I hope this is some little help, Steve G
4:03 am
JimB;7667 wrote: I am familiar with the ribbon burners and plan on building one eventually, but for now I just want one of those oh-so-easy pipe burners that everybody's always talking about 😉
I came up with a few ideas to try tomorrow and I'll post something about my findings.
fwiw, bite the bullet and build a ribbon burner now. your gas consumption will be about half of what you are considering, and the heat factor will be 100% greater. A little more effort will go a long way.
Short of that, build a venturi forge.
Forget a blown pipe forge. They are the most inefficient.
JE
4:57 am
November 8, 2010
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Sorry to keep digging this thread up 🙂 🙂 🙂
I thought ribbon burners weren't recommended for smaller forges. My forge only has a 0.25 ft^3 chamber so I was kinda iffy on the ribbon burner.
Any experiences with building them that small?
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5:58 am
March 22, 2010
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That is a pretty little forge, I dont know, John? ever build I micro ribbon burner forge?
Whatever you are, be a good one.
Abraham Lincoln
7:07 pm
May 22, 2010
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Why not just reduce your pipe and ribbon burner proportionately to the size of your forge, I don't see why that would not work. It might, however, make it a bit more of a challenge to make it smaller! =)
:bounce:
Brad Roland :hot:
12:33 am
May 14, 2010
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Larry L;7988 wrote: That is a pretty little forge, I dont know, John? ever build I micro ribbon burner forge?
Larry....
I just ordered a 2" square ribbon burner from Joppa. I will be building a small (1/4 to 1/3rd cubic foot). This burner works with a venturi (I am buying from them also), so there is no blower needed. I am still searching for a quieter forge. This may be it... Hope so.
After I get it working, I will report on it.
Grandkids and blacksmithing... Joy Joy Joy..............................YouTube Channel: djhammerd
4:01 am
November 8, 2010
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This forge is HUGE compared to my first one @ 144 in^3 😉
Shouldn't be too difficult to build a smaller one. I'll know all about it after I finish building it 😉
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4:43 am
May 14, 2010
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JimB;8048 wrote: This forge is HUGE compared to my first one @ 144 in^3 😉
Shouldn't be too difficult to build a smaller one. I'll know all about it after I finish building it 😉
A cubic foot contains 1728 cubic inches. The forge I'm hoping my new burner will support (quietly) will be less than 400 cubic inches in the burn chamber.
Grandkids and blacksmithing... Joy Joy Joy..............................YouTube Channel: djhammerd
6:41 am
November 8, 2010
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Yeah doubt I'll need anything near a cubic foot anytime soon 🙂 The little 144 in^3 one was a small pile of fire bricks with a single venturi burner heating it.
I was looking at the burners sold by Joppa and they look pretty solid.
Probably close to what I'll need for mine
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