[TheForge] Re: reducing fuel costs by improving forge efficiency.

Mon Aug 2 08:07:51 EDT 2004

        Marc,  Am I correct in saying the 12" tank with 2 1/2 inches of
insulating material leaves a 7" finished forge?   If so I see why you get
the decent heat.
        What size are the burners in this forge - 3/4?

        What are you talking about heating a lamp base with the lid ends up?
Does it not heat well laying down?.......or is this a three legged colonial
lighting fixture base your talking about?

        I'm curious as to what made the castable hard to mold to shape?  The
mix is too watery and settles? or the insulation had to be affixed to the
lid somehow? or does it just stick to the metal and you have a finished lid?
Is there any need for stainless holding brackets at the edges?  I've never
worked with this material so I was asking. You seem to indicate you'd go to
Kaowool next round...........would that be blanket your thinking of? or the
M board?
        I find the blanket much cheaper than the board.  The board does have
the ability to hold in a flat plane - but I'm dissappointed in the
replacement costs when I drop something and it flips up and hits the board
breaking it.  I have found the folded stainless edge components to have held
up well in the lid after five years of use.  This is also mostly because
I've kept the bricks under them so the direct flame travel is not on them
all the time.  I"ve wondered how the Kaowool blanket in a domed lid would
work out.  If you had stainless edges to support the arc of the blanket, and
the blanket was coated with a reflective glaze - it would certainly be
cheaper than the M board. (about 1/3)
        The best option would be if you could fasten the blanket in a flat
lid somehow to stay up and not fall in.  I wonder how stainless bolts and
washers would hold up to the intense heat of the center of the ceiling
panel.  Right around the burners, the ceiling gets intensely hot in my
forge.  Thoughts on how to keep the blanket up and flat could leed to the
cheapest option for a ceiling.  A blanket would dent or the coating might
get broken, but it would be very easily repairable.........the M board is
all done when it breaks and falls.  You only get to use it in smaller forges
as replacement insulation then.
        I'm actually thinking of making a smaller forge to accomadate the
three half sheets of broken M board I've got since running these two units.
Mostly I've been careful of not breaking the board, but workshops tend to
have folks who don't pay attention to it as much.

        One thing I question is how a domed lid would hold up for staying
straight.  I had to go to 1/4 x 2 x 2 angle iron to get my lid to stay
straight under the rising heat and not create "a curved shape" while
operating and coming off the bricks on the end.  By this I mean the lid does
distort and move, and the lighter angle iron I tried earlier, tended to
curve into a shape like a rocking chair runner (not as drastic, but about
3/16 to 1/4" up on the ends - allowing the gasses to pass by the stainless
full time).  I found the heavier angle iron and slotted holes for the
fasteners worked well and allowed for the movement during operation and
cooling.
        Does your domed lid stay straight? or does it warp up with
temperature?  This is another consideration in designing a floating lid.

        Your sliding rear wall is a neat idea.......... I've not used one in
my forge as the burners seem to generate so much heat I don't need to
contain it when doing 6-8 pieces at once.  The scale build up is tolerable -
but this could improve things.  I find the forge's "dragon breath" to be
much less when half the pressure heads out the rear opening.........it makes
for less heat transfer into longer parts, and less flame to singe your arms.
I've found laying a brick flat midway of the forge allows the flame travel
to go to the rear and still contain some of the heat for parts that don't
pass thru.  I also use broken bricks as insulation to control the heat into
less of the part for bending a tight radius.

        I'm real curious as to the best idea for a lid shape and fasteners
that will work with the Kaowool blanket used flat.
        For some reason, I'm not enthused about clamped bricks.  Paul had
run support rods thru bricks he'd put into his frame - it was a lot of work
on drilling, aligning, etc.

        Frosty's suggestion of bringing the burners in from the side is a
good one, as it keeps the lid less complicated.  Side burners would be easy
to mount.

Ralph


----- Original Message -----
From: "Marc Godbout" <marc at ironringforge.com>
To: "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Sunday, August 01, 2004 9:53 PM
Subject: Re: [TheForge] Re: reducing fuel costs by improving forge
efficiency.


> Hi, Ralph. I did use a tank. I cut the ends off of a 30lb propane
> cylinder, then cut the cylinder in half lengthwise. The two half were
> welded end-to-end to get my 18" length. I was going to try a bigger tank
> and not have to weld, but these are wider than what I was going for. The
> 30lb is the same diameter as a 20lb - 12". The next higher sizes start
> at 14".
>
> I find the hinged front and back very useful for wider things like lamp
> bases. It's much quicker than jacking up the roof and re-arranging
> bricks.
>
> The castable insulating refractory seems to be holding out real well. No
> falling rock yet :-). I also embedded some SS needles in the mix. It's
> supposed to help hold things together when cracks happen.
>
> If I were to do it again, I would probably use Kaowool for the roof
> insulation. The castable was a pain to mold. I would think the
> flexibility, compared with the M-board, would make it withstand the
> falling-pole problem. Maybe. But the simple cut-and-stuff would seem to
> be a simple way to insulate.
>
> The weight isn't bad at all. I think the roof, without the burners, was
> 35 lbs. That's 18"L X 12"wide (outside dimension), with 2" - 2 1/2"
> insulation thickness. The bigger tanks would have been a bit heavier, as
> they're 14" wide and the shell is thicker.
>
> As for getting a smaller insides, I've got a sliding rear wall with a
> "mousehole" cutout for long stock. This back wall is carved to match the
> arched ceiling. If I ever want to move the side walls in, I think I
> would just add a brick inside, instead. But I haven't ever tried that,
> and I'm not so sure why I would need to. The way the burners are mounted
> I get a decent enough spot heat.
>
> --Marc
>
> On Sun, 2004-08-01 at 18:58, Ralph Sproul wrote:
> >     Hi Frosty,  These considerations on how to build a forge
"top/ceiling"
> > were my
> > head scratchers as well.  I opted for the Kaowool M board as it is
> > hard/rigid
> .
> .
> .
> >      However, I see the picture on Marc Godbout's page of a domed roof
with
> > castable refractory as an insulation and it makes sense to me.  It
appears
> > he used a tank of sorts - and made his ends hinge up for more room to
stand
> > something in his forge. BUT when the lid is considered as a unit, it can
be
> > sealed
> > around it's perimeter.
> >     I think I'd leave these ends closed or welded on the domed tank
> > approach - be it a tank or a barrel with ends - and thus
> > solve the "sealing the ends" problem when moving in the bricks.
> >
> --
> Marc Godbout
> http://www.ironringforge.com
>
> New England Blacksmiths Membership Director
> http://www.newenglandblacksmiths.org
>
>
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