[TheForge] hybrid burners, reducing atmospheres, and SAFETY

[Ben Barrett]

So I've been following these burner threads, and now try to call my
venturi "atmospheric", and to call my buddy's forced-air + propane
setup a "gun burner"... so what qualifies as a "hybrid"? :)

More importantly, what tips can you offer in finding the sweet spot?
I have trouble finding it on my 3/4" mini-rex... I just got one of
Art's fine Montanan burners at the Spring NWBA conference, and haven't
hooked it up yet, but am anxious to try out my 2nd burner and learn by
comparison.
So far, I've been limited by a BBQ regulator, also, so I'm not
surprised that I'm having trouble tuning the rex.  I know it
deserves/needs better.

Anywhoo, is there something I can do by observing the little wads of
paper I toss in there?  I'm pretty sure my current/old setup is too
oxidizing, so it makes sense to slowly (say, session by session) turn
it back until the evidence of oxidization disappears.... surely there
are some good tricks out there from all y'all old-timers ;)

regards,

ben

PS - some said this conf in Enumclaw, WA was smaller than usual,
prolly due to being only a week after the one in California.  I had a
great time though, very treasured time in my smithing memory.  Thanks
to all who help make these conferences happen, and especially to the
extra attention to welcome new-bees like me :)


On 5/4/07, Kathy <keporter at comcast.net> wrote:
> The hybrid style burner has a facet I've not seen discussed; it tends to run
> with a slightly oxidizing flame. Each burner has a "sweet spot" in its turndown
> range, which is neutral burning with the choke wide open. However, throughout
> the rest of its range the choke must be used to keep from ending up with an
> oxidizing flame. This is no big deal as long as you're aware of the potential
> problem. However, all the comments about oxidizing problems in forges with
> hybrid burners has convinced me that it's time someone pointed out the obvious.
> Don't just open up the burner and adjust the gas pressure for flame size,
> thinking that this is all the adjustment needed. You must also choke the burner
> a little if you're outside the sweet spot.
>
> What Jerry said about the problem of free oxygen in a forge run on propane is
> also quite correct. It is truer of propane and methane than other fuels, but
> applies even to oxyacetylene. When you burn any fuel, there will be some fuel
> molecules, and also some superheated metal devouring scale causing oxygen
> molecules blasted out ahead of the wave front of accelerated flames. Whether you
> choke your burner to make a reducing (fuel rich) internal environment, or add a
> lump of charcoal to make sure the oxygen is eliminated before it can touch your
> work, is up to you.
>
> Whichever path you take, make darn sure that your working environment is
> protected from the carbon monoxide rich exhaust you will then be creating
> (powered exhaust hood and CO monitor).
> Mikey
>
>
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