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I Forge Iron

Forge Flutter/Huffing


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Hey all.  New guy here from Baton Rouge making my first post.  I'm glad to find this great resource.  Thanks in advance for your help.


I'm having some trouble with occasional flutter on my front burner, which when it begins to flutter causes a significant drop the temperature and the color of the exhaust changes to maybe more yellow and includes maybe a hint of green, and more volume of fire comes out the door.  I can't figure out exactly what the problem is.  My back burner doesn't flutter at all and the front one doesn't always.  It never flutters until it gets up to heat, and then not always.  But most of the time.  I don't always use the back burner, but if I turn it on, it helps the flutter problem some but does not eliminate it.  Also increasing the gas pressure at the regulator helps, but does not eliminate it. 


My burner set up post-50374-0-44422100-1388659629_thumb.j


Forge post-50374-0-29093500-1388659696_thumb.j


Several months ago, back burner only on first fire up before kaowool. The front burner then tested similarly.post-50374-0-09969400-1388659838_thumb.j


So I was reading earlier posts about other folks similar issues and then cranked it up yesterday to do some troubleshooting.  I think I've ruled out sucking in exhaust from the door.  I don't think that's my problem.  I made an attempt to shield the intake from the exhaust with a large piece of cardboard and it didn't seem to affect the flutter.  post-50374-0-39608900-1388661293_thumb.j  I'm sure I am getting breezes across the intakes, but I don't think that's the problem because only one burner flutters and the wind isn't normally very strong in this location.  Besides, it has run well in heavier wind than I had yesterday.


Yesterday, front burner only, shortly after lighting and before flutter began.  About 13 psi on the gas.post-50374-0-01616900-1388659904_thumb.j


Dragons breath after flutter began.  Maybe I've turned up to 20 psi here and added the back burner, but when there's no fluttering going on, I don't get this kind of volume outside of the forge.  post-50374-0-53247700-1388659937_thumb.j


I don't have much experience (next to none) with other forges so I'm not sure exactly how this thing should ideally operate.


My burners aren't exactly like Reil's in that I used 1 1/2 x 1 reducing couplings with a 1 x 3/4 bushing.  Yeah, I know - modifications...  I got what Home Depot had. Other than that, they are the same.  I guess that will be my next fix as there seems to be a consensus that intake flares really do need to be 2" x 3/4" reducing couplings.  So I'll see if I can round those up today and change them out. 


You can't see them in the photos but I'm using mig tips (.030" I think; 0.76 mm; they may be .025") screwed into the wall of the brass tube.  I don't like that set up.  There's not enough meat to that brass tubing wall for the tip to properly make up, It's sort of loosey goosey. But I think they are bedded in enough hardened thread compound that they are fixed and stable.  Still - not a great set up.  On another burner (a different application) I've mounted the tip differently - see pics.  I made this yoke to span across the opening of the bell post-50374-0-33212400-1388661058_thumb.j and mounted it like this. post-50374-0-72636700-1388661104_thumb.j It's much more solid.  Do any of you think it would be a mistake to mount the jets on the new 2" bells similar to the way I've mounted it on this alternate burner?  Yeah, I know... here I go with another modification but it's solid and I don't see any drawback. 


Also I don't currently have any baffles to choke down air flow.  Do you think I will need that with the new two inch bells?


For those of you who may be curious about my forge, I made it from sheet metal & lined it with 2" of refractory made of artist's clay mixed with sand.  It's real heavy.  I won't ever do that again and wouldn't recommend it.  It was a good bit of work and I couldn't get it up to heat. I just have so much mass there. So I broke down & put one layer of 1" kaowool in it.  It was about $50 for a 25' x 2' roll at the local welding supply house.  They wouldn't sell me a partial roll so I have plenty left over.  Man, that sure made a big difference.  Night & day!  Next time, it'll be just a housing and the kaowool.  I really think this could easily be set up in a metal rural mail box like available from Lowes/HD.  I'm seeing several pictures of fire brick forges on here.  To those guys I would say you'll be much much happier when you get some insulation in there.


I'll post what ever fix works.


Comments please.


Thanks guys.



BTW, I posted the pictures right side up.  Not sideways.  A preview of this post shows them sideways.  Not sure how to fix that.


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I'm far from a gas burner expert. And the only time I have the problem your describing is when I don't get the door open wide enough when I ligh the burners.
things that come to mind,
First have you experimented with how much you close up your openings?

Second most commertial forges have the burners closer to gether

Lastly my commertial forge runs on 5-15 psi wile many folks report their home built a working at 5 psi or less.
Again as I don't have a lot of experience building gassers I may be just posting to see myself type ;-)

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Thanks Charles.  I'll be sure to experiment with the blocking around the openings as you suggest.  And I appreciate your comments on the pressure.  As I said, I'm learning and I don't really know squat about how this thing should work.

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with my gassers huffing is generally indicative that the alignment of the orifice and the burner tube is slightly off or there is a very slight blockage in the orifice---something is not allowing  the gas stream to exceed the flame propagation rate.  Could be the size difference in parts too.


as to whether you need a choke the answer is Yes!, No!, Maybe?  depending on how you plan to use your forge; which you didn't list.


Forge welding and knife forging both can profit form being able to adjust the atmosphere in the forge.  If your burners do a good burn, ornamental work probably does not require one.


I advise trying a plumbing supply place rather than a big box store for parts.

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