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I Forge Iron

Let the chastising begin


Rolandag2

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I’m new no expert in this field. I cobbled together my forge burner from pieces that I had. I had a old grill burner with a knob that was threaded to 1/8 pipe and screwed into the orifice tube the bell was made from 1 1/2 pipe that was cut and belled to fit the 3/4 pipe. After installing the an adjustable propane regulator and test running it the thing ran better than previously. The knob is a great addition cause it allows me to turn down the flame and use less fuel. Please add anything y’all want as I’m looking for input I welded two pipes to make up the length. I took the pipe and turned it down internally to make it true. Outside doesn’t look professionally made but it works great. Again any input (good, bad, whatever) would be gratefully appreciated. PS I did check it for leaks and it’s sound.

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Sort of an older style Ron Reil burner.  His website has a lot of information about similar burners.  If you could provide an image of the flame it produces, that would help you get input.  Also, a better set of dimensions.  Are you using a mig tip in that cross pipe or just a drilled hole?  You state orifice tube so I suspect the latter.  What size orifice?  How long is the 3/4 pipe? 

Just looking at the pictures and taking some guesses here.  The 3/4 pipe looks to be on the long side and the reducer might be a bit small on the large ID.  This burner may have a problem inducing enough air.  An image of the flame can be looked at to see if this is true. 

Also, the knob is connected to a small valve which is most likely a brass on brass tapered assembly.  There is usually graphite grease but no real seal on the knob shaft.  On the bbq it was probably using 11" WC pressure which is about 0.4 PSI.  I am not sure how that will do with what you are throwing at it.  Either way, I have seen them at the 11" WC leak out the knob shaft.  In a few cases it ignited and sent a good flame out.  At higher pressures, I could see it not being fun.  While it can be used to meter to some extent, it is more of a guillotine.  Better control would come from a needle valve. 

All that said, it's a cool looking burner.  The last burner I thought might not induce enough air turned out a beautiful flame.  Did you bell the 1 1/2 pipe?  How did you go about it?  I look forward to seeing the flame.  Then some of the wise ones can chime in and if there are troubles they can give advise on how to make it better.

I also recommend burners 101 thread on this forum if you are into designing your own burner.  It is a long read but it has a lot of information on the science of burners and their parts.  

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Ok that’s what I wanted to know the knob will probably not stay on after the input I just got. The 1 1/2 x 2.5 pipe was cut along the length and hammered into shape then welded and cleaned up. I used #60 orifice and the 3/4 tube was a total of 9” long with the end being bell shape. I do have a adjustable regulator 0-30 psi regulator. I haven’t run it yet.

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That is a decent looking flame.  It weel heat.  Nice job.

It is a reducing flame which means it is not inducing enough air like I suspected.  It will heat as is but it will not get as hot and it is pumping out the carbon monoxide so be sure to be well ventilated as we all should.  Some people prefer to use a reducing flame as it can prevent scale building up in the forge.

If you want to make it better, the first thing I would try would be shortening the mix tube(3/4 tube).  You stated it as being 9 inches but you also say with the end bell shape which I am not sure I follow.  The general rule of thumb for a starting point length is 8 to 9 times the ID of the mix tube.  If you have a mix tube diameter of 0.824 in(3/4 pipe) then this would be 6.9 to 7.4.  If you go this route, start longer then that and cut off a little at a time.  Can't add it back after you cut it off and all that business.  

Other things that could be done are increasing the size of the end reducer and looking into using a mig tip instead of a drilled hole for the jet/orifice.  Both of these would be more difficult then cutting off lengths of the mix tube.

All that said, I wouldn't do anything until the experts give their opinions as my knowledge is limited and I would not want to steer you wrong.  Also, the flame looks good and can be used as is.  One of my forges has a burner which has a more reducing flame and as long as I am willing to accept the increased fuel usage and carbon monoxide it makes the forge plenty hot.  

Also, to note, even though you plan on refractory in your forge, it is still recommended to rigidize your ceramic blanket.  You can do that before the refractory and use your burner to heat cure it.  On page 2 of Forges 101 is some information on the process.

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2 minutes ago, AnotherCurtis said:

That is a decent looking flame.  It weel heat.  Good job.

It is a reducing flame which means it is not inducing enough air like I suspected.  It will heat as is but it will not get as hot and it is pumping out the carbon monoxide so be sure to be well ventilated as we all should.  Some people prefer to use a reducing flame as it can prevent scale building up in the forge.

If you want to make it better, the first thing I would try would be shortening the mix tube(3/4 tube).  You stated it as being 9 inches but you also say with the end bell shape which I am not sure I follow.  The general rule of thumb for a starting point length is 8 to 9 times the ID of the mix tube.  If you have a mix tube diameter of 0.824 in(3/4 pipe) then this would be 6.9 to 7.4.  If you go this route, start longer then that and cut off a little at a time.  Can't add it back after you cut it off and all that business.  

Other things that could be done are increasing the size of the end reducer and looking into using a mig tip instead of a drilled hole for the jet/orifice.  Both of these would be more difficult then cutting off lengths of the mix tube.

All that said, I wouldn't do anything until the experts give their opinions as my knowledge is limited and I would not want to steer you wrong.  Also, the flame looks good and can be used as is.  One of my forges has a burner which has a more reducing flame and as long as I am willing to accept the increased fuel usage and carbon monoxide it makes the forge plenty hot.  

Also, to note, even though you plan on refractory in your forge, it is still recommended to rigidize your ceramic blanket.  You can do that before the refractory and use your burner to heat cure it.  On page 2 of Forges 101 is some information on the process.

Thank you so much Curtis I thought the mixing tube was to long and planned on cutting 1/2” and testing and tuning 

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No problem.  As far as I know it currently, as you cut off mix tube, you reduce the length of drag which allows the burner to induce more air, however, you are also reducing the amount of length it has to mix the fuel/air so it is a balance.  

If you do go ahead with cutting off mix tube, you might look into different nozzle designs (in your case the threaded area you tapered at the end of the 3/4 pipe) since you will be cutting off your nozzle anyway.  Having a separate piece for a nozzle allows more adjustability as well as not having to make a new nozzle each time you shorten the length of the mix tube.

Once again though, I would do nothing until the experts give their opinion.  They may come in and say I have it all wrong.  

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Curtis has it right.

I would add that you should make one change at a time. The change to a MIG tip (.023") should be your first move, and may be all your burner needs. Fortunately you got the tapering of the mixing tube's end just right for this burner.

Lots of folks that are watching should make note of that.

The MIG tip should make it easier for you to align the jet orifice down the tub's center axis, which I think will not only fix that off-side flame, but contribute greatly to making it hotter. Afterward you may decide to leave well enough alone, and make no further modifications to your burner; we shall see.

The problem you will encounter is getting the tip to screw into the burner with the gas pipe in place; that will be needed, as I don't think it will have room to turn inside the reducer without hitting its wall. The answer is to drill a hole in the end of a section of wooden round rod (old mop or broom handle); make it the same 1/4" diameter as the MIG tip, so that the tip fits snugly, and insert the assembly down the tube. When the tip screws tight into the threaded side hole in the gas pipe, pull on the handle as you revolve it off of the tip.

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  • 2 weeks later...
On ‎12‎/‎21‎/‎2018 at 8:11 AM, AnotherCurtis said:

No problem.  As far as I know it currently, as you cut off mix tube, you reduce the length of drag which allows the burner to induce more air, however, you are also reducing the amount of length it has to mix the fuel/air so it is a balance.

Yes, it is a balance. How radical the flame retention nozzle is (step nozzle versus lightly tapered nozzle versus strongly tapered nozzle) is another factor in that balance, as the more radical the increase in air induction is the more mixing tube length it will tolerate.

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