[TheForge] Modified Side-Arm Burner Troubles

[Marc Godbout]

I think the two things you mentioned hurt your chances for a proper
flame. Blue wisps are unburned propane, but I'm not sure why you
couldn't light a match in there. I would expect enough air from the
entrance to get you a nice bang.

Anyway, I used a 1 1/4" cross fitting on mine. That's the type with four
openings. For the 3/4" mixing tube, I used a 1 1/4" X 3/4" bushing. And
I drilled through a plug for the gas supply. The first go-around had
poor results. Not enough air was getting through. I had a flame, but I
also had quite a bit of propane running out the exits unburned.

So I used a carbide burr on my die grinder to carve a funnel shape into
the bushing. That improved the flame a lot. Next, I drilled a new plug,
this time with the cross fitting attached to the plug. This way I could
better center the gas supply. Again some improvement.

It still wasn't where I wanted it to be, with too much unburned propane.
But my design had a huge design change. I was using a 90deg sweep of
rigid conduit instead of a straight nipple. Conduit is galvanized, and
that left a rough surface inside the tube. I removed the galvanization
(don't ask how) and now it works the way I want it. I get welding
temperatures and have to choke of the air at high pressures. It also
works all the way down to a candle flame.

One last thing, make sure you have enough opening to allow the gas to
escape. A closed-in forge will cause back pressure. For me it meant that
the flame was igniting way back at the gas jet.

Hope this helps.

-Marc

On Sat, 2003-12-27 at 15:17, DillonCo wrote:
> I'm having trouble with my modified side arm burner
> (http://www.geocities.com/zoellerforge/sidearm.html).  Although it works
> well outside the forge chamber, when I light it inside, the flame quickly
> destabelizes (at any pressure).  The flame disappears and very light (cannot
> be see in daylight) blue wisps come out of the exhaust (at are visible in
> the chamber).  I believe the problem is insufficient oxygen because I cannot
> light a match in the chamber after turning off the propane.
> Can anyone help?
> BTW, it's not built perfectly.  I used a symmetric T and a bushing instead
> of an a-symmetric T, and the plug wasn't drilled quite straight (at propane
> nipple is about 2.5* of level).

-- 
Marc Godbout
http://www.ironringforge.com

New England Blacksmiths Membership Director
http://www.newenglandblacksmiths.org