Bryan Hannis on mon 9 oct 00
Can anyone tell me what are the best grates to use in a wood fired kiln?? I
have been thinking of using strips of high alumina shelves 1"x2" by 9" long
but also could cut fire bricks to that size or even silicone shelves to that
Please email me direct.
vince pitelka on mon 9 oct 00
> Can anyone tell me what are the best grates to use in a wood fired kiln??
> have been thinking of using strips of high alumina shelves 1"x2" by 9"
> but also could cut fire bricks to that size or even silicone shelves to
> Please email me direct.
I'm posting this to the list, and hoping others do, because I would like to
see what they have to say about it.
I like wood kilns without grates, because any grate design reduces the
radiated heat from the coal bed. But if you decide you need them, I would
not use anything breakable - brick or silicon carbide. You are far better
off looking for a cheap source of thick cast iron or steel bar or rod stock,
and designing the firebox to make it as easy as possible to replace the
grate-bars. They can be replaced via removeable plugs in the front or side
of the firebox, dependent on which way the grate bars run, which is in turn
dependent on the shape of the firebox and the location of the stoking port.
Small-gauge steel railroad track, such as is used in mine tunnels works very
well. Large machine shafting (2" O.D.) or large bar stock works well. For
the money, the best grate-bars are cast iron, because they do not warp
easily like steel does. If you know of an old-style cast iron iron foundry
in your area, you might consider having them cast some up for you. It will
be a very simple open pour, with little cleanup, and shouldn't be too
expensive. Industrial Revolution cast iron grate bars were wider (top to
bottom) in the center than at the ends, to give greater strength.
Good luck -
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David Hendley on tue 10 oct 00
I've always considered my grates to be a 'consumer item'.
In other words, you use them up and then buy more.
In my 'fastfire' design kiln, it's easy to pull out the old
ones and put in the new ones.
I use 1" diameter 'sucker rods' for the grates. Sucker rods
are used in petroleum well drilling, and in Texas, they are
readily available. The drilling companies replace them on
a regular basis, and they are a favorite for gates, fences,
and hay holders.
I don't know what kind of steel this is, but it is pretty
durable. A set of grates lasts for several years, maybe 40 or
50 firings. For the frame the grates are welded to, I've used
more sucker rod (failed too quickly), 1 1/2" diameter chrome
plated steel shaft material (better), and hardened steel
plate from a grater blade (best).
I coated my current grates with the ITC for metal product
and it failed completely - made no difference and was gone
after 2 firings.
I think this might have been because the grates had already
been used without the coating. When Alice heard about the
failure, she sent me another jar of ITC. I'll be making new
grates in the near future and will give it a try on the new set.
| > From: Bryan Hannis
| > Subject: wood fire grates
| > Can anyone tell me what are the best grates to use in a wood fired
| > have been thinking of using strips of high alumina shelves 1"x2" by 9"
| > but also could cut fire bricks to that size or even silicone shelves to
| > size?
Terpstra Karen K on tue 10 oct 00
More info would be helpful. How big is the fire box? what kind of kiln is this? How
long are the firings? to what temperature?
I just read Vince's post that says he prefers not to fire with grates and wants to hear
other opinions so here's mine. Keep in mind that there are countless ways to fire and
each wood firer finds a way that works with their own kiln. It ends up being a very
We like using grates at school where we fire with lots of novices and inexperienced
people. We've found that students rarely choke the kiln, and can "read" what's going
on. We can see when it's time to stoke; i.e. are the logs ready to fall apart on the
grates. (we use other factors too in determining when it's time to stoke, but this is
easy for beginners to check.) We don't have to stir much or do all that bending down to
clean the mouse holes that often---anything to eliminate work during a firing!!!! (I'm
not as old as Mel, but....) Anyway, I've fired without the grates too and just prefer
this way with students.
We are experimenting with truck axles from the junk yard. Sandblasted them. washed them
with bleach. brushed on (thin) ITC 100. just finished the 2nd firing and we'll see how
long they last. I will keep you informed if you are interested. I am using them
because i want the option to fire without grates if i want. I can easily remove them
from the fire box.
When or if I get tired of the truck axles, I will most likely have some custom bricks
cut. (depending on funds). I wouldn't trash shelves. too many other uses for good
Assistant Professor of Art/Ceramics
University of Wisconsin-La Crosse
> From: Bryan Hannis
> Subject: wood fire grates
> Can anyone tell me what are the best grates to use in a wood fired kiln?? I
> have been thinking of using strips of high alumina shelves 1"x2" by 9" long
> but also could cut fire bricks to that size or even silicone shelves to that
Steve Mills on tue 10 oct 00
I'm posting to the list for the same reasons as Vince.
I use steel piping, rather than the more commonly used rods, as they
withstand heavy use better. Joe Finch uses long kiln posts which can be
renewed easily when they (inevitably) break. I use only one or two
rather than a lot, as I can then tip the fuel at an angle and get a
broader flame front; better combustion therefore greater heat.
In message , Bryan Hannis writes
>Can anyone tell me what are the best grates to use in a wood fired kiln?? I
>have been thinking of using strips of high alumina shelves 1"x2" by 9" long
>but also could cut fire bricks to that size or even silicone shelves to that
>Please email me direct.
Terpstra Karen K on wed 11 oct 00
Oops. I used ITC 213 for Metals on the axles. Not ITC 100.