[TheForge] claying a forge

[Andy Vida]

Ron wrote:
> 
> Howdy folks, I know this has cropped up before but what are the recipes
> for lining a cast iron portable forge. I know some think it is
> unneccessary but I'll be lighting this puppy up in cold shop usually and
> I don't want to crack the pan. Also I don't think I need to line the
> firepot either. The forge is an old buffalo forge cast iron deal with
> the side arm to hold the blower. Any advice appreciated.

	A few things.  First, I've never tried to use refractory
	cement.  It may not be a good idea, but installation would
	be easier than fire clay.  Next, if you use fire clay, you
	want the clay to be as dry as possible when laying it up.  
	I lined my rivet forge and the clay was a bit too wet.  The
	clay shrunk a LOT, pulled away from the cast iron bed and
	cracked all over the place.  Obviously the clay must still 
	be in a plastic state, so leather hard is not going to work,
	but very, very dry I would recommend in order to minimize
	shrinkage and checking.  
	
	After it sets up and dries to your satisfaction, light a
	"tame" fire in it, allowing the forge to come slowly up 
	to a mild temperature.  This will drive out the remaining
	moisture.

	If the clay cracks in places, not  to panic.  Make a slip
	from your fire clay and pour it into the cracks.  When it
	dries, it may crack again if the fissure was large.  Fill 
	with more slip and let dry.  Keep doing this until it
	no longer cracks.  Give another mild heat if need be, and
	then you should be good to go.  I would suggest that you
	raise the temperature of the forge slowly your first time
	out, just to play it safely.  Remember that the fire clay
	will not vitrify, so water will always be the enemy, so  
	keep the forge as dry as you can.  Dry fire clay is pretty
	tough, in my experience, and should last a long time if
	you take care of it.

	-Andy