[TheForge] Fanning the flames

[Daniel Kretchmar]

Paul,
        When some friends and students made mine based on Aldren
Watson's book, we made a few changes.
1. I scaled it down so that I could make all 3 paddles (2 paddles and
one center board) out of a single sheet of plywood.  I used 1/2" thick
mock wainscoting.  It came with grooves cut in it every 6" to make it
look like separate boards.
2.  The ribs were made from 2 pieces of 3/4 inch flat stock that I
attached to the leather with washers and pop rivets on the inside.
3.  I made the flaps from some 3/16" luan plywood that had been part
of a shipping crate.  We covered the flaps with suede and installed
them in a removable panel so that we could do maintenance on the
inside if we had to. The rectangular panels had enough room for two 9"
air holes. The panels were attached to the paddles with 3 inch lath
(3" x .25")  After several trials, we ended up having to cut the air
intake holes to 9" in diameter.  Anything smaller and they wouldn't
let in enough air.
4.   The final change was to make the nozzle out of 2" pipe so that it
would fit the air intake pipe that is attached to my Civil War Box
forge.  I have one side of 2" pipe union on the forge and the 3 copies
of other side of the union attached to the bellows, the crank blower,
and the last one connected to a squirrel cage blower with a dimmer
switch. The pipe union makes it easy to assemble and switch air
sources if I have to.  I NEED to make an anti-flashback box with a
flap going toward the forge, but with an interior lip to prevent the
bellows pulling air from the fire.  I learned that as long as there is
air in the top lung, it is okay to fill (lower) the bottom paddle, but
if the bottom paddle is somehow prevented from dropping while the air
is blown out the top lung, then the lowering of the bottom paddle will
draw air from the forge. I charred some of the wood inside the
bellows, but that is all.  Now I make sure never to hold the arm down,
or pull to slowly.  I just never seem to get around to making that
anti-flash back box valve.

I can send send anyone pictures of my bellows that were taken during
the trial run.  Drop me a line privately.

Danr

On Sun, Dec 19, 2010 at 8:00 AM, Paul N <crosspein at sbcglobal.net> wrote:
> I'm thinking about building a double-lung bellows as a winter project.
> (Actually 2 of them, one for myself, and a second to use as a working
> facsimile at a historic site nearby)
>
> I have two references ("The Blacksmith, Ironworker and Farrier" by
> Aldrean A. Watson, and "How to Make a Blacksmith's Bellow" by Robert M.
> Heath) The designs are very similar, but not identical. These are big
> boys, about 38" across, and probably 5' long.
>
> I'm wondering if anyone on the list has any advice to offer. I was going
> to make the paddles and ribs out of 3/4" plywood instead of the 1"
> planks described in the books. I'm also wondering if I can get by with a
> naugahyde or similar sides to avoid the expense and maintenance of leather.
>
> I'm thinking that if the plywood isn't heavy enough to draw air, I can
> hang some weight on the bottom paddle as needed. Similarly for the top
> paddle. I can pile weight on top of it as necessary.
>
> This sounds workable, but I'm wondering if anyone tried this and found
> it disappointing, or perhaps had a suggestion to offer.
>
> **Paul
>
>
>
> ______________________________________________________________
> TheForge mailing list
> Home: http://mailman.qth.net/mailman/listinfo/theforge
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:TheForge at mailman.qth.net
>
> TheForge mail list group photo site is
> http://www.photoworks.com
> Login: blacksmithblacksmith at hotmail.com
> Password: anvil
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>



-- 
"Estattu alvarligt, nei?"