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I Forge Iron

1/4" Frosty T burner


twigg

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Took my first crack at 1/4" T burner. I'm still waiting on 3/8" x 1/4" reducing tees, so for this initial attempt I used a 3/8 x 3/8 tee and a 3/8 male x 1/4 female hex bushing.

Parts:

  • 3/8 x 3/8 black iron tee
  • 0.6mm 3d printer nozzle (M6 x 1mm threads)
  • 1/8" NPT x 1/4 flare fitting adapter
  • 3/8 male x 1/4 female hex bushing
  • 1/4 x 2 black iron pipe nipple
  • 1/4" x 1/4" stainless coupling
  • 1-1/2" cutoff section of 3/4" pipe
  • 4 screws 8-32

 

IMG_20210210_193529.jpg.611ea7efdc5e758530ae2b0b511f28ab.jpg

 

As far as the instructions, it's pretty much a standard frosty T burner except it uses the 3d printer nozzle instead of a mig tip. After drilling and tapping the 1/4 flare end of the brass fitting, I file the tapered end off (same as in my 3/8" burner build). The one thing I will say is that I made sure to tighten the hex bushing into the tee until it sat flush with the inside surface of the tee. This is to imitate a 3/8 x 1/4 flare as closely as possible, for the "funnel" effect.

The flare nozzle is pretty crude, it's just what I had on the fly. This was very much a kitchen-sink build. I center it using the 4 screws.

And here's some pretty pictures for you pyros out there:

IMG_20210210_193152.jpg.e6037dfa8bcfaeb625583bc758665b06.jpg

I'm hoping some further improvements, starting with a true 3/8 x 1/4 tee will reduce the secondary flame and increase the heat.

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The reducing tees arrived today, and I tried a bunch of things. I tried varying the mixing tube length from 2" to 3", and I swapped back and forth between the 3/8 x 1/4 tee and a 1/4 x 1/4 tee. I also built a slightly better nozzle from spare parts. I found the 1/4"x1/4" tee made the leanest flame and also got the nozzle hotter than the 3/8 x 1/4 tee. I really couldn't tell you why the smaller air inlets gave a leaner flame. The 2" mixing tube length gives the best results.

IMG_20210211_180300.jpg.36ad0d8ff5ab153413f4639cba419a8b.jpgIMG_20210211_180305.jpg.80f6ac0120a5d0ed50880e875a779356.jpg

At least now I can't see any red in the tertiary flame with the lights on. I think that's an improvement. Also, the turn-down range is now below 1psi, whereas before it struggled below 4psi.

Lastly, I mounted it up in my two brick forge (2-1/2" ID), and it swirled nicely with an angle: (skip to about 0:14 in the video, there was a malfunction with the dummy holding the camera)

It doesn't get the forge as hot as my 3/8 burner at 7psi did, no matter how many psis of propane I put into the 1/4" burner. There's very very little dragon's breath though. Below 10 psi, there's only clear exhaust gas, no flame. I'd like it hotter though. I think two of these 1/4" burners could be the winning ticket for my two-bricker. I also need to do more experimentation with nozzles.

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Welcome to the club.  I spend as much time tinkering with burners as I do actually using them. 

A lathe also makes drilling the tee concentric with the mix tube a piece of cake.  

If you are trying to squeak out every drop, spend most of your time on drilling that hole as close as you can get it.  Having the orifice off just a little can reduce induction dramatically.  

The smaller the burner, the smaller the error to screw up things.  Nice job on the tiny burner.  I like the mini forge as well.

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I forgot to measure my errors on this last run, but that could totally be why I got a leaner flame from the 1/4" air inlets than with the 3/8" air inlets. I'm limited by an annoying amount of quill slop in my drill press. If I'm careful to get the hole centered, I can still wind up with crooked threads because the spindle tilted when I chucked the tap. A real lathe would be nice, but I work on borrowed space and everything I own has to be portable. Time to re-read the southbend book before I make any decisions

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