T-Burner Mod

[goofyboson]

I'm working on a small mod to Frosty's T-Burner.

I had purchased a 3/4" T-Burner, but the nozzle was visibly out of alignment. Also, it seemed that the Venturi effect wasn't properly tuned (depth of mig tip), since the flame would blow itself out unless the air inlets were nearly entirely choked off, though maybe this was the nozzle alignment too.

To solve these problems I'm thinking of running propane through a threaded pipe that screws into an adapter on a pipe cross (rather than a Tee). This should roughly center the nozzle, while also allowing a variable mig tip depth.

This approach requires the 3/4" npt(m) x 1/8" npt(f) adapter to be tapped to nps, and the ends of the 1/8" nps pipe to be died out to npt. The rest of the build is just assembly.

Does anyone see anything glaringly inadequate or dangerous about this approach? I'm still waiting on some parts before I leak test and try to light it.

[Steve Sells]

We have an entire section devoted to gas forges, perhaps you will get better information if this was posted there, I will move it for you.  Read through the section and you  may get some ideas

[goofyboson]

Thanks Steve! I'm still learning my way around. I've read through several of the introductory threads, and am working through Porter's book now. Certainly a lot to get through.

[Steve Sells]

there is no reason to rush, enjoy the read and you will get more from it than when rushing through.

[Latticino]

Nice mod,  Adjustable nozzle location is one of the things that has always been an issue for me with the T-burner.  Only problem I see is whether reducing crosses are available...

[Buzzkill]

I have a couple thoughts here.  

First off, one of Frosty's early designs used a threaded lamp rod to adjust the depth of the mig tip in the reducing T.  I believe he found that to be more hassle than it was worth and concluded that trimming the mig tip was preferable for tuning in the long run, but if I have the reason wrong I'm confident he will correct me.

Secondly, By using a cross with 3/4" openings all the way around, you limit the air induction somewhat compared to a 1" x 3/4" reducing T.  That will probably produce a more stable flame, but limit the maximum temperature that can be reached and probably also result in a fuel rich burn throughout the operating pressure range even with the mig tip pulled back as far as you can with that arrangement. 

Thirdly, unless you have a flare on the end of the mixing tube, properly tuned T burners tend to blow themselves out when outside the forge and frequently even inside the forge if the pressure is turned up too much before the forge chamber starts glowing.

I'll be interested to see what your results are, but I think what you have done is tamed the beast by limiting its potential.

[goofyboson]

Awesome! Thanks for the input.

I was unaware of Frosty's lamp rod design, I'll have to hunt it down.

The 3/4" cross will certainly increase air inlet impedance, though I could cut out the threads to bring it closer to the 1" in the original design (and maybe reduce air inlet turbulence? Might check with FEA).

At some point it's reinventing the wheel, and if I go that far I might play around with some of the 3D-printed Venturi designs. At this stage I'm just trying to get my forge warmed up, so I'll plumb this out, but also throw together a standard T-Burner.

 

[Frosty]

Originally I used lamp rod and  tapped the T. The problems I ran into was finding fittings to sub to the Mig contact tips without making my own. I also have 3, 3/4" crosses in a locker that I found more work than just drilling and tapping a T. Even when I got them tuned I had to use a smaller mig tip to tune to 3/4" air ports. 

My conclusion where cross fittings ran like this: Crosses are expensive, and don't have 1" female ports, requires a reducer to make up to fuel supply, reducer being pipe thread makes the fuel supply rod less secure so it can be moved out of alignment. Nothing I found produced as hot a flame, less intake air means you MUST introduce less fuel and the fuel jet moved around so it wouldn't burn properly no matter what. And no, turning the threads out of a T for air intakes didn't improve things enough to make it worth the hassle AND you need a lathe to do it properly. 

I can drill and tap a 1" x 3/4" T fitting in under 15 minutes and buy ALL the fittings off the shelf in a proper HVAC plumbing supply for about $10.00 in Alaska. A big box like Home  Depot or Walmart rarely has suitable fittings on the shelf. 

A good method for making an threaded fitting to adjust the mig contact tip is to tap 1/8" scd. 80 pipe nipple to match the mig tips available at the welding supply, a REAL welding supply, NOT the big box. Your welding supply will carry the correct tap and matching drill bit for the mig contact tips they carry, it's common to need to chase the threads in a mig gun. If the mig tip loosens during use it can arc, damage the threads and require chasing so welding supplies carry bits and taps on the shelf.

Anyway, 1/8" scd. 80 plumbing nipple is close to exactly the right ID but may need to be chased to tap. The outside of the nipple can be threaded full length after trimming the pipe threads from the end making up to the T. Use the pipe threads on the other end to make up to the propane supply line.

This mod to the basic T is popular and discussed repeatedly in the Burners 101 sub section of propane burners section. 

The fittings I specified in the illustrated directions are getting harder to find and are intended to make up to 1/4" copper tubing directly on the burner. My shop forge has vertically mounted burners meaning a significant amount heat chimneys up the burner on shut down or is blown through any that aren't running while in use. I felt rubber supply hose ON the burner was susceptible to burning AND was susceptible to being bumped. Bumping the hose could knock the gas jet out of alignment. Copper tubing running to a manifold is not only pretty immune to chimney effect or exhaust flame from another when the burner is shut down plus being no chance of someone tripping over it, settled the issue for me. My set up has a rubber hose from the regulator on the propane tank that makes up directly to a 3/8"  plumbing pipe manifold. From the manifold 1/4" copper tubing makes up to the 3/8" x 1/4" T via appropriate bras fittings. I like flare fittings as the flaring tool works with many sizes of copper tubing as seen under sinks and toilet in the main house.

Frosty The Lucky.

[goofyboson]

Thanks Frosty, you've made my options quite clear! Seems this cross design is a quick and dirty approximation to what you suggest with the 1/8" scd. 80 nipple, and trading power for flexibility isn't what I'm trying to do. I'll use a basic T-Burner for now, and revisit the variable nozzle depth when I have nothing better to do.

[Irondragon Forge ClayWorks]

9 hours ago, goofyboson said:

learning my way around.

Have you read this yet?   READ THIS FIRST  It is the best thread with tips for learning your way around the forum.

[goofyboson]

I have, thanks!