17 years ago
a coating of colloidal silica and zircon. I can say that the forge is
definitely hotter with the ITC-100.
before it would get to a good orange heat, with maybe half of the
inside at a "strong glow" at 5 p.s.i. Now, with the ITC-100, at 5
p.s.i. the whole inside has a "strong glow" and it gets to yellow for a
six inch radius where the burner flame hits the floor of the forge.
The IR shooting out of the forge is much more intense... I wear a
kevlar glove, and if I leave my left hand by the opening for more than
about 30 seconds it'll start to smoke... I've had to start misting it
with water from a spray bottle...
For the next person to try it, here's some notes:
More insulation is better... I don't think you need more than a 3"
thick layer, but I'd go for at least 2" of ceramic blanket.
I soaked the fibers of the ceramic blanket with colloidal silica, let
it dry, and then painted on some more silica and zircon. I don't
remember the proportions I used, but it was, maybe, as thick as light
cream... I needed to make more of a thick slurry and add a lot more
zircon. Also, the zircon I used is fairly fine mesh stuff. The ITC-100
is a lot more coarse, more like the grit on 120 grit sandpaper. (I
don't know of that matters)
It would have gone better if I used a mister to spray on the silica,
and then let it *almost* dry out, and then added another layer of
silica & zircon. The coating gets pretty crunchy when it dries, and the
cracks (from brushing on another layer) don't really go away. Once it
dries it doesn't really get "soft" again. It's better to do the coating
all-at-once then one layer every couple of days.
If you can, spray it on. Brushing works, too, but spraying causes fewer
I'd try mixing in some satanite, or some other refractory clay, too.
The ITC-100 has some clay in it, and I can tell there is a difference,
although I'm not sure how to explain it. It just seems tougher with the
clay in it.
It's been a hoot making this thing and fooling around with it. I have a
couple of ideas for making a "poor mans" recuperative forge, so I think
I'll make one more... I'll take pictures and keep you all posted.