[TheForge] Chip forge

[Jeffrey Polaski]

I'm just curious, but does anyone have any experience to say how what
the effects are? Has any one tried a forge with different chips?

I'm not sure, but this is how I think of what's going on in a chip
forge. It's purely conjectural, but these are my working assumptions:

	1.) Start with a running and heated forge
	2.) Cram some metal in it. 
	3.) Chips near metal cool down as they radiate heat into cooler
metal 
	4.) Metal starts to heat up
	5.) Hot gas swirling by heats the metal, too
	6.) The cooled-off chips around the metal start to heat up
	7.) As chips heat up they (mostly) radiate more heat into the
metal
	8.) Most of the heat put into a piece is from:
		a.) Hot gas swirling by
		b.) Radiated from the chips
		c.) Physical chip-to-metal contact plays a fairly small
role (not a lot of contact, due to chip size (i.e. 1/2") and, because
we're talking about heat flowing *from* an *insulator*, it's not going
to deliver a lot of heat all at once. 

Given this, I think that a *lot* of thermal mass would be a drawback.
That is, the column of cooled-off chips (from when you just crammed in a
metal bar) would take *longer* to heat up with more thermal mass. I
think this would make it take longer for your bar to heat up, too.

Just a thought, but has anyone put a flat "clamshell half" over a chip
forge to radiate heat back into the pile
	

Jeff Polaski
Research and Graduate Studies Webmaster
University of California, Irvine
http://www.rgs.uci.edu/
949.824.6363

-----Original Message-----
From: theforge-bounces at mailman.qth.net
[mailto:theforge-bounces at mailman.qth.net] On Behalf Of xlch58 at swbell.net
Sent: Monday, March 06, 2006 1:01 PM
To: Sponsored by ABANA
Subject: Re: [TheForge] Chip forge

Rich Maynard wrote:

>I think shape has little or no impact on the heat transfer, as others
have
>commented, other than by using a shape that packs more densely the
thermal
>mass is increased for a given material.
>
Shape does have a major effect on heat transfer.   Since the heat is in 
the gas and the goal is to use the chips to absorb the heat from the gas

and feed it back to the metal, therby avoiding sending such a large 
percentage up the flue, the heat transfer plays a big role.  I suspect 
the thermal storage aspect would be important if the heat supply was 
variable, but it is not. 

Charles


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