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Nicodimas

Propane Forge

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Hi All,

I recently got my first propane forge, it's 100k BTU model, but I cant seem to get it going correctly. I have it attached to a 20 pound tank if this is relevant pressure wise? I was told I should be able to at least get it going, its a fresh..brand new tank.

I started it about 4 times and have tried the following

Keeping at a lower pressure and it goes out...

At higher pressure it starting cutting in/out and sputtering. However...

1 and 2) At the Burner itself fire appears around there and the rubber area and I am forge to turn it off as that can't be normal having fire at the tip of the burner.

So take #3---4 Turn it on again and have it about 18/20 setting and it rolling...then it starts "sputtering" and cutting in and out.

I am then again forced to cut the gas and retry. This was my best attempt..Any advice.

*) It should not have flame at the burner itself..correct?

 

 

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Post some pics of the forge and burners and I bet someone here can diagnose the problem.  A video should help too. 

Tke the time to add your location to your profile and you might find someone right around to corner from you to trouble shoot it

 

russell 

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I'm betting on it being a air problem. To much or to little is the hard part to figure. frosty is the expert and I'm sure he will chime in sometime. Go read the stuff on the gas forge page if it well come up and see if any of it sounds simalur to what yours is doing. What brand is it by the way?  Did you check for dirt dobbers in the burner tubes and rust in the orfuses?  A lot of times that solves a lot of problems

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That's pretty normal at low pressures. The propane pulls the air in behind it/with it, so you've got to have enough pressure for it to work.  Mine does that until I hit about 3 psi according to my gauge, then the flame will stay in the forge at the end of the tube like it's supposed to.  I don't know what kind of tuning options/choke plates, etc you have, but you may have to make some adjustments to the burner as well.  Have you tried slowly increasing the pressure to see if it will stay lit in the forge with the flame at the end of the tube or have you just shut it down when that happens?

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The best method of troubleshooting it would be to bring it to a local smith that has experience with propane forges.

What did they say when you brought it to a local meeting?

as mentioned sputtering is usually a function of pressure or alignment ---What kind of regulator are you using?

Edited by ThomasPowers

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I have been reading around and found this information and this sounds what is occurring then, I have the choke fully open to.

http://www.atlasknife.com/graham-100k-burner

^ This one.

 

If the flamefront speed exceeds the mixture speed, at first the flame travels back down the burner tube until it runs out of mixture to burn. With nothing to burn, it goes out. The gas keeps flowing and it draws air in, so fresh mixture reaches the chamber after a short delay, ignites in the hot chamber and the flamefront again travels back down the burner tube. This cycle repeats, with each occurence heating up the burner tube slightly and increasing the flamefront speed of subsequent events, until the flamefront establishes at the point of mixing in the Venturi throat. The noise made during this is distinctive and you can usually just turn up the gas pressure and stop it if you catch it in time. If you leave it until there is an established flame in the throat, the burner tube gets properly hot and it's often not possible to just turn up the pressure and get the flame back where it should be.

Edited by Nicodimas

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I haven't worked with that particular burner, but if it came to you assembled I would hope that the manufacturer got the alignment correct.  Thomas gave you the failsafe advice.  If there's anyone in your area who runs propane forges they should be able to sort you out in short order.  If you want to give it another shot on your own then bring the pressure up within the first 10 seconds or so of lighting it.  You just need to get the flame down to the end of the tube before the tube has a chance to heat up.  Otherwise you'll have to wait for it to cool down again or it will continue to burn inside the tube.   If you don't have a flare on the burner it will not stay lit outside the forge either, so you have to do this with the burner in place.

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Thank's Y'all. I am in classes too out here for the foreseeable future..(until next June). So i will probably ask the teacher this week and bring it by..

This will be my second class...(they are running a Natural Gas//or a Coke setup) 

Just so close to figuring it out and want to get hammering!! on my own to practice this stuff that I am learning....

Edited by Nicodimas

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My LP forge works good but I still gave up on it unless heat treating. Too costly,noisy & temperamental for newb such as myself.

I love my charcoal/coal brakedrum forge. I make my own charcoal or use coal from tractor supply for little cost with more consistent results and more versatility aswell.

Edited by jacob's hammer

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I cant quite figure out the video.  was that the end of you burner?  If it was, and it had no flair on the end, it probably wont work outside of the forge.  that has been my experience at least. 

 

Russell

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The ad for that burner that the link takes you to says it won't run outside the forge. That design IMO looks like it needs to run at higher regulated pressure. It then requires the forge to choke down the exhaust to keep the flame from blowing out.

Do you have a pressure guage to monitor lp pressure going to the burner? That will help, bottle pressure typically drops off some after you have it running for a little while and that regulator appears to be a single stage so inlet pressure will effect outlet pressure.

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Long reply disappeared 4 times! So I'm in a BAD mood. Please forgive me if I'm cranky.

Welcome aboard, glad to have you.

You need to tune burners where they're going to be used so mount them in the forge. Also don't worry about what psi someone else's burners run, there are too many variables for it to be useful information unless they live down the street from you. Altitude is a biggy, humidity and ambient temp effect performance. Barometric pressure at Altitude is effected by wind patterns for instance if you live on the west side of the Sierras your barometric pressure will be higher than someone living at the same elevation on the east side. The point is do NOT fret about trying to get YOUR burners to work at someone else's psi.

The sound on your vids tells us more than the pics. Next time back away so the whole burner is in view and shoot against a dark background so the flame is clearly visible. With them mounted in the forge this means a shot straight in the forge so we can see the flame then another shot of the whole forge from the side so we can see the dragon's breath. Again against a dark background.

Mount your burners turn the psi up start at maybe 5+lbs and close the chokes. Light ONE burner. There SHOULD be yellow billowing flames coming from the door maybe 12-18". If not increase the pressure till there is or it's billowing 3' turn it down. A little judgement is called for here.

Now with the yellow dragon's breath somewhere around 12-18" SLOWLY start opening the choke till it's roaring. Examine the flame. If you're familiar with using an oxy acet flame you know what to look for. Torch flames have 3 parts, the primary central or core flame, opaque light blue, the secondary flame is darker blue and transparent surrounding the primary and extending farther from the torch tip. Finally is the tertiary flame which is much more transparent and soft even feathery or fluttering at the very end.

The tertiary flame in a forge is what we call "Dragon's Breath" and comes out the forge door. It shouldn't extend very far, a few inches if good, 6" is good. It should be clean blue with NO yellow and at most a hint of orange. The orange in the dragon's breath indicates it's running a little rich producing a reducing atmosphere in the forge. This is a two edged sword, a reducing atmosphere will prevent the steel from oxidizing IN the forge this is especially good when welding. Unfortunately it means the forge is making more Carbon Monoxide, (CO) than it needs to. Any fire will consume oxy and produce exhaust including CO, gas forges especially propane forges make a LOT of CO. Good ventilation is a MUST and CO/Fire alarms are a REALLY good idea.

Keep a notebook and Note: psig, the sound and volume, flame shape including dragon's breath, time till the forge temperature plateaus and it's color.

Don't forget to tune the other burner too. ;)

Well, that's the basics and with a little practice you'll be the local GURU, it's really pretty easy once you get the hang of it. The gauge's real utility is so you can repeat target temps without having to tune for them, different materials and processes like different forge temps. Note what works and more importantly what doesn't work in the notebook.

If you run into problems give me a shout.

Frosty The Lucky.

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You mentioned getting a new 20 pound tank. Many states used the compulsive replacement of old five gallon propane cylinders with upgraded models featuring overflow devices as an opportunity to also quietly include internal pressure limiting devices that are capable of running a barbecue, but hopelessly under-powered for running a typical burner. If you ended up with one of these tanks, it will never provide sufficient gas to power even the smallest NA burner. Should this be your problem, buying a much larger tank locally or buying a new five gallon tank in another state are your only solutions.

Mikey

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Every naturally aspirated burner has a "turn down range; this consists of the amount of input pressure to the gas jet between the maximum jpressure, above which the flame blows clear off the burner, and the minimum input pressure, below which the flame becomes erratic and finally burns back into the mixing tube. These are pretty straight forward adjustments and easily gotten used to.

But, most NA burners need to be choked back until they warm up; then the choke sleeve or choke plate can be opened all the way. This is such a basic problem that most of us forget it's a real surprise for newbies.

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On a NA burner what would be considered more important when constructing? Maintaining smooth airflow so it can induce as much air as possible or not really worrying about that so any turbulance created helps mix the air and propane more in the tube as well as the outlet lip/flare.

I am wondering if I should lower the propane velocity with a larger mig tip so the heat stays in the forge a bit longer?

The burners I have made so far have been the Ron Reil improved designs and I did what ever I could to improve airflow, blended out the seam in the pipe, blended where the tube joins the reducer and generally cleaned any burrs ect. Carefully adjusted the aiming of the mig tip (.035) to shoot straight down the middle. 

When running the burner it will run lean without a choke and when tuned with the choke for a neutral flame the choke is probably 80% closed. It runs stable from 1-2 psi up to 30-35 psi. By the time I get to 6-7psi its really starting to roar and by 30 the outlets of the forge look like rocket exhausts.

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Naw, the weld seam in the pipe won't generate enough turbulence to do more than improve mixing. Stable from 1-2psi up to 30-35psi is outstanding? It sounds like your burner's working fine, I wouldn't tinker with it much. Why don't you bring it to the January meeting so we can all get a look at it?

If you want to experiment with the jet put the one in it now in an envelope or little box and label it. Experiment on another mig tip, that one works a treat. If you start with the same size you can enlarge the orifice dia. a little at a time with torch tip files. It's a lot less risky than drill bits, copper can be tricky jamming and breaking bits.

Frosty The Lucky.

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Frosty has it right,

But you can also use MIG tips the next size up, and insert capillary tube in them, in order to come up with the orifice you want without drilling, there are many ways to get around drilling in copper; all of them are better than drilling.

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I used torch cleaning files to clean and size the mig tip. I learned the hard way about trying to drill the tips on my wire feed trying to resize on when I had to replace one on a Sunday in the middle of a project! 

I will look in the thread but if its not there, when and where is the January meeting?  I have been trying to make it to one for a while now but its like a jinx, something always seems to come up at the last minute!

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I knew I forgot to write something down at the last meeting. Darned TREE! I put the question out I'll post it in the Alaskan Association section here when I hear back. Till then I'm writing a note to myself before I hit "Submit."

Frosty The Lucky.

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One of things you must do is to dump that propane cylinder and get a 100 pound or larger.  Any cylinder that has a triangular handle will not work well.  Those cylinders have an overfill device, and also a valve that closes when the output volume exceeds a certain amount.  To reset that valve you need to close the cylinder valve and let the gas in the outlet hose go away.  A small cylinder will also freeze up and that will restrict flow as well.

The larger cylinders are easier to find in rural areas where propane is used more.  I got mine at a big box hardware store in a rural area for 1/2 of what the local propane supplier was asking so try that route if you live in an urban sprawl like I do.

Sometimes, the flame will not really stabilize until the forge heats up and lights the gas as it goes in.

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Got this working, went to a open forge and found out..there was shipping material stuck in the line.  

 Forgot to post a response..or It didn't actually go through.. 

Works really well and Yea I definitely have to start it and turn it up as it gets hotter. I definitely will be investing in a larger cylinder in the future.

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