Subject: Re: forced air or carburated?

From: [email-masked]
Date: Thu, 04 Jan 1996 12:06:45 EST

Subject: Venturi or Blower
  
The book, How To Build a Gas Forge, illustrates a forced air forge.
What are the pros and cons of either the naturally aspirated or the
forced air gas forges?
  
I would like to build my own, and have aquired 30 or 40 refractory
bricks that should do the job.
  
Thanks
Vance

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*  Message From : BURNS, VANCE A.       *
*  Location     : US-HOUSTON(IS3) LAN   *
*  KOMAIL ID    : FVAB94  (IS3     )    *
*  Date and Time: 01/04/96  11:43:01    *
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From: Steve Smith <[email-masked]>
Date: Thu, 4 Jan 96 11:00:29 MST

I've built both types of forges. Both work very nicely when you get
all the wrinkles out.

My blower forge is a piece of water pipe 12" diameter and 18" long. I
have 2" insulation in it, with a fireclay poured floor. It will hold
large items, like car coil springs nicely. Works well, not much
finesse required to make it work. Not very portable due to being HEAVY
and requiring a cord.

I just finished a prototype no-blower forge. It is heavily cribbed
from the Abana/Rob Gunter design, with some changes, such as:

	double doors (left and right) 
	no preheat on incoming air (only dropped the temp by 120
		degrees F or so, MUCH simpler burner assembly).
	1.5" wall insulation instead of 1"
	modified air inlet horns (flared like a trumpet)

I'll sell sheet metal for $150 plus shipping, or show you plans for
cost and give tons of free advice. When I'm sure I have a stable
design, I will be submitting it to the online resource list.

Big Clue: flame holders (as discussed in your book) are needed with a
blower; they won't work worth beans in a no-blower! Just leave the end
of the tube open (the opposite wall/floor acts like a flame holder).

I'll be happy to help you with more details. I like both forges, but
the portability of the naturally aspirated one is a big plus.

--
Steve Smith
[email-masked]