[TheForge] hello

[Jerry Frost]

> if i were to line an BBQ grill with clay,what type of clay should i use
> and how thick should i make the lining?
>

Good question. Clays are not all created equal; every so often somebody
posts about using kitty litter, wondering why it isn't working. Kitty litter
is clay but it's non-bonding and non-firing. Not all clays, most in fact,
won't cement themselves well enough to hold together when dry and a good
percentage of the ones that will won't fire and remain dry clay.

Fire clay is cheap and common at your local masonry supply, concrete
company, furnace/heating supplier and many building suppliers. Even here in
Alaska I can buy a 50lb. bag of fire clay for under $20 so even though I
know of several sources of excellent native clays I spend my time and money
more economically at the concrete plant. Depending on where you live you may
have good native clay available and here's a simple test.

Take a decent sized sample, say 2-3 cups worth and dampen it just enough
it'll make a nice hard lump when squeezed in your fist. The lump should
break cleanly and not leave anything but dusty crumbs on your hand. If it
leaves mud it's too wet, if it crumbles it's either too dry or the wrong
kind of clay.

Once you have the sample prepared and it passes the lump test, use a mallet
or wide faced hammer and ram it HARD between a couple 2" x 4"s to make a
test brick about 3-4" wide. Let it dry a day or so and see if it stays in
one piece, crumbles, gets dusty, etc. (this is called "friable") If it stays
reasonably solid and non-friable, start a charcoal briquette fire in the
5lb.+ range and nest the test brick in the pile, under at least a 2
briquette layer. Doing this in a hole in the ground is a good way to contain
the briquettes and not need a bunch.

Let it burn out and cool naturally. If after it's cooled it's in one piece
and still non-friable it'll be fine in a forge and you can move onto making
it into a "refractory" liner. The test is harsher than conditions in your
forge will be but that's as it should be. If it passes the tests, living as
your forge liner will be a breeze.

Whether you're using commercial fire clay or are lucky enough to have native
clay to work with, you don't want to use it straight. Mix it about 1 pt in 4
with coarse sand and add about 1pt. in 6-8 portland cement to that mix. If
using commercial fire clay, mix the clay and portland cement dry first, then
add the sand. Pre-wetting the sand is the easiest way to get a uniform
moisture in your mixture. The clay will want to clump around water droplets
and little wet spots, the sand really helps prevent this. Regardless, mix it
till it has a reasonably uniform moisture content and passes the squeeze a
lump test. This is a pretty standard test for green sand casting to test the
"temper" (moisture content) of the sand and works the same for clay liners.

Once you have your liner mixed and ready, use a wooden mallet to ram it into
your forge pan till it's nice and hard. You will of course want to leave
your air grate open so cover it with something like a disc of wood as thick
as your liner is going to be. If you wrap the edges of the wood disc in a
couple layers of newspaper it will come right out of the clay when you
remove it: The paper just slips off itself and you won't damage the freshly
rammed liner. Remove the disc as soon as you're finished ramming the liner
in.

If you're using a brake drum for a firepot, cut a hole in the pan so the
drum rests on the flange near the rim and make the liner come just to the
top of the rim.

Once it's rammed up, use a butter knife to score it in even sized and shaped
sections. Making shallow (1/4" is plenty) cuts with the butter knife, etc.
will make the shrink/heat checking (cracking) a controlled process instead
of a random and possibly damaging experience.

How thick it should be depends on a couple factors, mainly what the pan's
made of. To use a couple extreme examples: If you're going to make the pan
from 1/2" plywood the liner should be several inches thick to shield it from
the fire. If it's made of 1" steel plate, 1/2" of clay will shield it just
fine. About 1 1/2 - 2" is a good general depth to line a light weight sheet
metal pan such as a BBQ.

Another trick to make it more durable is to run some sheetrock screws
through the pan from the outside so the clay has something to hold onto.

Once your liner is rammed up and scored, let it dry for several days,
hanging a lightbulb in it works really well in damp climates. If you live in
the desert you may want to loosely lay plastic over it to keep it from
drying too fast and checking severely. Once it's well dried, put a 3-4
briquette layer of charcoal over all the lined surfaces and light it up. Let
it burn out and cool naturally and she's ready to go to work.

Something else about BBQ forges, they tend to be too deep so a good thing to
do is make a couple "gates" in opposite sides to pass your stock into and
through. Basically take a sabre saw and cut rectangular notches in opposite
sides of the BBQ forge pan. Make them the same width as your firepot, 9-12"
is plenty and cut them down to about 2-3" above the top of the firepot. Just
for clarity when I say sides, I mean the hinged lid is opening away from the
smith and is the back; the same orientation as when used for grilling
burgers and dogs. Of course you can make the gates in the front and rear if
you wish, it's up to you.

Keep the cutouts so you can make doors out of them. Scrounge some small
hinges and use pop rivets, screws, or whatever you like to mount the cutouts
on your forge pan. Hinge them from the bottom so they'll be out of your way
when open and mount or make a latch to hold them closed when not in use.

Without being able to pass long stock into and through your forge you'll be
limited in what you can do. NOT limiting yourself is one of the most
important things you can do for yourself. Don't however, try to design a
forge nor anything else to do EVERYTHING. A tool that does everything does
nothing well.

Speaking of forges I need to get out and light mine, I have a couple sign
hangers to make.

Frosty
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks

Meadow Lakes, AK.