[TheForge] propane forge

[Dave Brown]

At 10:42 04/08/02 -0400, you wrote:
>Dave Brown <quahog@tds.net> wrote:
> >the Sandia style box forges.  Still, I'm somewhat swayed by the 'swirl'
> >argument.

I think that the Sandia gets most of it's advantage from the preheating of 
the intake air via the intake manifold/heat exchanger.  Still, btu's in vs 
btu's out implies that round vs box furnace combustion chambers of 
equivalent volume would perform about the same.  The recuperative style 
benefits from increasing the btu's in for the same volume of gas supplied 
btu's.  It's a bit of a quandary, but the bottom line is that we will each 
gravitate to what works best for us.  Right?

>This is the site for the Swan forge I don't see the Mini Mother, but the 
>Mother is there, http://swan-portaforge.co.uk/ The picture really doesn't 
>show how well it works. Don't get me wrong, I don't believe that any forge 
>is the answer for everything. But it worked really good, I like the door 
>system as well.

Interesting site.  The doors lift straight up, right?  I can see where that 
might be an advantage over a drop open door or a swing out door, and 
is  probably in the same class as the doors that pivot upwards.

> >My large propane forge (10"ID" uses a piece of round flue liner (not clay,
> >it looks like some sort of compressed ceramic fibre like kao-board).  This
> >made a great inner liner for the forge.

>i would like to get some ridgid board but my supplier will only sell it in 
>the box. It would be about 10 times more than I need, making it rather 
>expensive. Where did you get the flue liner that you have?

Keep in mind that flue liner is a different thing than rigid ceramic 
refractory board.  It's only about 1/4" or maybe a little more 
thickness.  Also, it is NOT a clay liner like they use in home fireplace 
chimneys.  It is designed for large industrial flues and chimneys and will 
deteriorate somewhat when used inside a forge/furnace combustion 
chamber.  Look for a larger industrial supplier of firebrick and refractory 
products, it's a relatively common item for them and comes in a variety of 
shapes and sizes (square, rectangle, round, elliptical, etc...)  and comes 
in short lengths just like clay chimney liners do.  You must use another 
insulating refractory (e.g. Kaowool) around the liner if you use it in a 
forge.  I forget the price I paid.  The flue liner will protect/preserve 
the Kaowool and when it becomes necessary to change it is a lot 
cheaper.  But like Kaowool, first you have to find a local supplier ....

Where are you located?  The last place I saw flue liner was up in St. Paul, 
Minnesota.

Dave