Dunbear

T burner flare questions

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My take on a Frosty T burner. 

  • I've been reading everything I can on this forum but its my first time building a forge so please bring me up to speed if I'm off on something. I've built a T burner following Frosty's method, had to make some minor changes on how the mig tip is mounted  due to lack of available hardware in my area. The problem I'm running into is when I use a thread protector on the end of my burner as frosty suggests I cant keep the thing burning (not slowing down the gas enough?) but when I put on a bell reducer it works without a hitch. This brings me to my question of what to do with the flare end inside of the actual forge? Will the issues I'm having with the thread protector be negated by having the burner in the actual forge environment/making a bell from the ceramic wool/kast-o-lite or should I increase the size of the hole in my forge wall to accommodate the larger bell reducer that I know will produce a good flame? Any insight into the area where the burners enter the forge would be greatly appreciated. I'm hoping to get a solid plan together before I start putting in my wool/refractory materials. 1101180933.thumb.jpg.74bdb4f7a4ce559b419322c62d8be643.jpg
  • 0.035 mig tip, 6" pipe nipple, 1x3/4 T joint, 3/4"x1 1/4 bell reducer 
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The burner will almost certainly behave differently inside the forge.  Without seeing a flame in either configuration it's difficult to tell if it's tuned somewhere near right outside the forge.  Regardless, it's best to tune the burner in the environment it will be used.

A quick observation on your burner though - you have a lot of length in your fitting arrangement going into the T.  That can potentially allow for a lot of leverage on the connection at the T, which can throw off your jet alignment in the least case or result in a break in the worst case.  Obviously a broken gas line there with a running forge is not something you want to experience up close.

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I was thinking the same thing in regards to the leverage on the T. I plan to support it when it gets installed on the final product. When I get back to the shop ill try and take a photo of it burning to help clear things up.  

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Im located in western South Dakota. Yes the teflon tape is rated for propane. The link youve provided has some good tips, Thank you. 

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Welcome aboard Dunbear, glad to have you. Telling us where you live now isn't going to stick in our minds once we leave this post. If you put it in the header anybody seeing your header will know where you are. 

Making a home built burner well enough it'll burn properly in or out of the forge is really ticklish. Tune it where you're going to use it. 

Point 1, as Buzz says you have a dangerous amount of junk between the supply hose and T, lose everything. put a "Street elbow" in the fitting welded to the T and you can connect the hose directly. However I recommend a little distance between the T and anything flammable like the propane hose so a short nipple is good, 2"-3" max. I run 1/4" copper pipe between the hose and burner so I don't have to care how hot it gets or flames shoot on it, etc.

You don't need very large supply lines to the jet, it's 0.035" ID the supply pipe only needs to be maybe 1/2 again as large, say 0.050" ID to provide all the gas it'll need. No, don't go looking for tubing that small, I use copper refrigerator tubing and flare fittings. 

It's light and flexible so it won't knock the jet out of alignment. Jet alignment is the single most important construction detail to get right!

Being flexible if someone trips on the propane hose nothing will break, sure it might kink the line or even jerk the forge around but it's not going to break the copper line nor produce an unregulated fuel fire.

Flares. Until recently I KNEW a bell reducer flare wouldn't work, then a bunch of guys started making them work and work better than my burners usually do. So, a bell reducer is just a matter of tuning for it. Same for a thread protector or coupler, it's just a tuning issue. No biggy, you gotta tune it anyway.

I'm not a fan of the size penetration through the shell and liner necessary to use a bell reducer "flare." Guys do it though so it's just a construction detail.

Other guys shape the refractory to produce the flare successfully. It's a little bit of a mess but not bad and potentially very effective. The problem is getting the right flare. I've never messed with doing it this way so can't say. I like it though.

Thinking about it before submitting the post I realized I do use refractory to shape burner nozzles, see the NARB. Start with something simple though.

Frosty The Lucky.

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Thank you for the advice, ill definitely re-work the gas supply. In my head i was thinking the farther away i could get the gas hose the better but i see your point loud and clear. Here is a video of the burner running, not sure how well its tuned as this is my first go, but its much improved over anything i got playing with the thread protector as a flare. 

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You're welcome, it's my pleasure. I don't know what kind of video file that is but once I looked I couldn't shut it off. A still pic works as well, I can see the flame velocity is pretty high even with the bell reducer. Have you tried turning the PSI down?

Agreed, the farther the hose is from the forge the better, within reason. Trip hazards are to be avoided if at all possible.

Frosty The Lucky.

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That was an mp4 file perhaps the issue has something to do with how I uploaded it. Here is a still picture. I do not have a gauge on my regulator so I'm not sure what psi that is but I have a wide range where I can still hold a flame so turning it down shouldn't be an issue. My main concern is keeping it from producing too much CO2. Id rather not die a tragic death if it can be avoided.

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My bad, carbon monoxide is what I was after. Any tips on keeping the CO produced by the forge to a minimum?

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You'll find yourself at cross purposes there.  Yes, you can minimize CO production by running a fuel lean mixture.   However, this will cause your steel to oxidize inside the forge and create more scale, which means more loss of stock and potentially more carbon burned out of the steel while you are heating it.  We normally intentionally run a slightly fuel rich mixture.  We know that will produce more CO, but it also limits or eliminates the formation of scale on the steel while it is heating in the forge.  Of course once you remove a piece from the forge scale will form almost instantaneously when it hits the normal atmosphere outside the forge.   As said already, if you are going to forge indoors, get a CO detector and place it a few feet from the forge - roughly the distance you spend most of your forging time.   If you forge outside there shouldn't be much of an issue unless you are constantly intentionally standing in the exhaust gas stream.

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As I sometimes forge blades I tend to run rich and ventilate the heck out of my work space. We have had folks ask: "is opening a window in their garage is enough?" My reply is that I open two 10'x10' roll up doors on opposite ends of my shop along the general wind pattern, I have 10' walls and open gables; that seems to work for me...

What really causes issues is when your forge re-runs previous exhaust back through---why I don't like vertical burner plans a greater chance that hot exhaust rising can get cycled back through.

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