[TheForge] Re: Gas forges (burner adjustments)

Wed May 8 21:34:01 2002

        Frosty, I'd love to see some pictures when you get done some trial
and error.  I had a blast doing mine.  Look forward to seeing what your up
to.

Ralph


----- Original Message -----
From: "Jerry Frost" <[email protected]>
To: <[email protected]>
Sent: Wednesday, May 08, 2002 7:30 PM
Subject: Re: [TheForge] Re: Gas forges (burner adjustments)


> Hi Ike:
>
> I don't remember if I replied to your post but don't think so. Also I
> normally wouldn't be getting back till thursday or friday night but I have
> an infection in a toe and being diabetic have to take it pretty seriously
so
> I'm hanging out, keeping off my feet, taking my antibiotics and checking
> E-mail.
>
> You have a huge forge, close enough to 4,700 cu/in as makes no difference.
> To reliably get welding heat in a naturally aspirated propane forge the
rule
> of thumb is 1 ea. 3/4" burner per 300-350 cu/in. In your forge this would
be
> 13-16 ea. 3/4" burners. A 1" burner has twice the output of a 3/4" burner
> but you'd still need 7-8 of them.
>
> My advice at this point is make a smaller forge unless you REALLY need the
> volume. Even if you do need the space I'd make a couple forges rather than
> try using one so large. If I needed one 19" long for heat treating blades
> I'd make it about 4-5" dia. and manifold a number of 1/2" burner nozzles
to
> it from a couple 1" Jet Ejector type inducers. Then build a 12" dia. 12"
or
> so long forge for scrolls and other large volume things.
>
> It's been my experience I can't hand work more than a few inches of stock
at
> a time unless it's a twist, scroll, etc. Most of the time my 6" dia x 12"
> forge with 4" x 6" openings at either end works just fine till I bend
> something then I can't get it back in. <sigh>
>
> One reason blown (gun burner) forges boast low gas supply pressure is
> because of the diameter of the supply line. The larger the supply line,
the
> less pressure you need to supply the same amount of fuel. Gun burners are
> easy to make and tune but tend to be more expensive to build and are tied
to
> a power source. Naturally aspirated burners are cheap, I have less than
> $9.00 in my latest and it'll melt steel in my little forge but they're
> harder to get tuned.
>
> I'm presently working on a forge based on Ralph Sproul's new design. It's
a
> departure from the clamshell design. There is a fixed refractory table
with
> fire brick sidewalls and a refractory lid. The lid is mounted to a jack
and
> can be raised or lowered as needed. The sidewalls can be moved in or out
and
> up or down as needed.
>
> What I'm doing is using 2 1/2" of the ends of a 55gl. drum for table and
> lid. I've rammed up the table but am still working on burner placement for
> the lid. I'm EXPERIMENTING with home made insulating refractory for the
> backer. It's made up from perlite and fireclay without waterglass, furnace
> cement or any of the other possible ingredients. The part meeting the fire
> directly is rammed up using a 4,000f high phosphate refractory that is
> unfortunately unavailable anymore. I'm going to ram up sidewalls in the
same
> manner.
>
> I'm going to form the final burner nozzle flares from the 4,000f rammable
> refractory so they won't burn off. As people are getting burner efficiency
> up they're finding they can't keep nozzles on them and refractory is much
> cheaper than jet or rocket engine alloys would be. <grin>
>
> The basic chamber is going to be 8" x 8" x 8" with 4 ea. 3/4" burner
nozzles
> on a 6" square pattern, driven through a manifold by a 1" jet ejector type
> inducer. Okay, that's easy enough but the trick is going to be the outer
> burner nozzles.
>
> I want to put the outer 4 burner nozzles 16" apart, 45* off the main/inner
> burners. The trick is going to be valving them so I can use them in
whatever
> combination I need. If I can pull it off I can have a forge chamber as
small
> as 6" x 6" x 2" h. to as tall as 20" without remounting the jack, expand
it
> to 18" x 18" up to 20" h., make it 6" w. x 18" l. up to 20" h. or any
> combination in between.
>
> That's probably enough rambling for now. <grin>
>
> Frosty
> ------------------------
> If it ain't forged
> it ain't real.
> Wrought iron is.
> The FrostWorks
>
> ----- Original Message -----
> From: <[email protected]>
> To: <[email protected]>
> Sent: Sunday, May 05, 2002 12:11 PM
> Subject: [TheForge] Re: Gas forges (burner adjustments)
>
>
> >
> > I know that I have been a lurker and Haven't posted anything in a while
> but
> > here goes.
> >
> > I have used an old home made propane forge that is 19" long and 13" dia.
> with
> > 2 atmosphere burners. It was originally made for making long blades. It
> has a
> > number 60 dill hole in the tips. I can't get to welding temp but I can
get
> my
> > heat up and keep stuff workable i.e. 10 1/2" square HR stock in it at
one
> > time. I usually am set at about 10 psi at start and drop to 5-6 psi
after
> it
> > warms up.  I have had very few problems with it and I like it as a base
> > forge. I have seen blower assisted gas forges that can almost melt steel
> in
> > it and use about 2-3 psi on it. I have seen those forge weld all day
long
> and
> > after the day was done they replace the fire brick and continue to work.
> >   I have also seen small 8" long and about 8" dia. atmosphere forge heat
> s-5
> > and s-7 stock up to heat and put into a 25# little giant and forge them
> down
> > to punches and other tools.
> >
> > I have not cleaned my tips in my forge for about a year. I have not had
> any
> > problems with it except for my tips that come through the kaowool.  I
> ended
> > up drilling a hole and putting a screw in and the tip of the screw
melted
> off
> > in about 20 hours of burning.
> >
> > A lot of us here in AZ use propane due to pollution problems here. Most
of
> > the forges are blower assisted types. I think that the style came from
> > someone putting a drawing in a blacksmith newsletter. I have a copy of
the
> > drawing in a book published by the AABA from stuff published by ABANA
> chapter
> > newsletters.
> >
> > I use a 10x15 tent frame with silver tarps for my roof to keep the sun
off
> of
> > me. No walls in the summer. Work at night if possible.
> >
> > I am a hobbyist blacksmith.
> >
> > Later Ike
> > Pan's Forge
> > But it is dry heat.
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