Flame spreader

I’ve wanted a simple flame spreader tip for a propane torch for many years.  I recently got around to looking on Ebay etc, but couldn’t find a cheap one.  It helped when I saw a picture of one that wasn’t fully enclosed.  I figured I could make something with an open back like that, so I did.

A piece of 3/4″ copper pipe slit open should provide good starting material, so I found a scrap.  To help me understand what I’d be doing in bending it up, I first made the shape up from scrap cardboard.  That was a very useful exercise.

A couple of cuts with a hacksaw and some flattening and I had the basic starting shape.  I can’t believe I was dumb enough to make the cuts by eye without measuring.  I really do know that I can’t get away with that, and now I have yet another embarrassingly asymmetrical physical reminder of that.  Maybe someday I’ll learn.

Another surprise (that I should have foreseen) was that it gets really hot.  That means it oxidizes a lot and is unpleasant to handle after it cools down.  So it’s asymmetric, ugly, and dirty.  But at least it works about as I’d hoped.

It’s not like a bunsen burner flame spreader where the flame is all outside the spreader.  Here the hot inner cone of the flame directly hits the spreader.  I even reshaped the spot it hits so it would spread out a little more.  Flame pictures are always a challenge, so I used the CHDK firmware in my little Canon to get widely bracketed  exposures and picturenaut HDR software to make this one.

The spreader is basically successful and certainly functional, and it also serves to remind me (again!) to never cut anything without measuring first.

GaveUp3359Update 12/1/15:  I’m not sure what happened to the spreader.  I sort of think it fell behind the bench – a fatal fall.  Anyway, I gave in and bought one.  Looks like Bernz discontinued them, but you can get anything on Ebay.  I drilled a hole so I can hang it near the torch NewSpreaderInPlace3361heads.

I haven’t even fired it up yet, but I expect it will become my new go-to for bending plastic.  Interesting progression.


BenchLighter3413Update 12/3/15:  I always use spark lighters to light the torch (that doesn’t have electronic ignition), so it was an interesting lesson to learn that those don’t work well with a flame spreader in place!  And trying to put the spreader on the torch after it’s lit doesn’t work out well, Lighter3407either.

But since I always keep a butane lighter on the electronics bench (for heat shrink tubing) and stock cheapies, it was easy to add an open flame lighter near the torch stuff.

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4 Responses to Flame spreader

  1. Com Entor says:

    Did you use a red magic marker to mark your lines or did you cut yourself?

    • Jim says:

      Yeah, it’s just red marker – thanks for asking. I’m happy enough to show my errors, but I do try to clean up the blood before I take pictures. :)

  2. Stacey says:

    Hi Jim
    I am wondering how you attached your homemade flame spreader to your torch ?

    • Jim says:

      Hi Stacey,

      It’s just a friction fit. It’s pretty easy to bend the sort of cylindrical tabs at the bottom (before you put it on the torch) so it stays on well.



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