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need a cup grinder for kiln shelves

updated wed 28 feb 07

 

Paul Borian on tue 27 feb 07


I have a diamond cup grinder made by Pearl, a very heavy duty and =
expensive thing that I bought several years ago when I got a whole set =
of heavily used kiln shelves for free and they needed extensive work. =
But I have found that this grinder is not the best thing when you just =
want to remove all the kiln wash from a shelf and apply a fresh coat as =
it tends to cut into the shelf sometimes. What I need is a cup grinder =
just like the abrasive discs and cutting wheels used on angle grinders =
for grinding metal, except in a cup shape. Anyone know where the best =
place to get them is? I think I would use a 4 =BD cup but use it on my =
7" grinder since it would put a heavy load on the smaller one and the =
shafts are the same. I don't see these things at the home improvement =
places.

Thanks,

paul

Michael Wendt on tue 27 feb 07


Paul,
I get mine at the welding shop.
They sell silicon carbide in cup
form.
I also recommend you get a
router speed control from
Harbor Freight and slow the cup
a lot. I had one fragment, hit me
in the knee and it was like being
shot... I practically passed out
from the pain so keep the speed
low and use a light touch.
Good Luck,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, ID 83501
USA
208-746-3724
http://www.wendtpottery.com
wendtpot@lewiston.com
Paul wrote:
I have a diamond cup grinder made by Pearl, a very
heavy duty and expensive thing that I bought several
years ago when I got a whole set of heavily used kiln
shelves for free and they needed extensive work. But I
have found that this grinder is not the best thing when
you just want to remove all the kiln wash from a shelf
and apply a fresh coat as it tends to cut into the
shelf sometimes. What I need is a cup grinder just like
the abrasive discs and cutting wheels used on angle
grinders for grinding metal, except in a cup shape.
Anyone know where the best place to get them is? I
think I would use a 4 =BD cup but use it on my 7" grinder
since it would put a heavy load on the smaller one and
the shafts are the same. I don't see these things at
the home improvement places.

Thanks,

paul

Robert on tue 27 feb 07


Paul,
You might also try googling Whitecap. They're a building supply outfit
that carries them.
Robert

Michael Wendt wrote:
> Paul,
> I get mine at the welding shop.
> They sell silicon carbide in cup
> form.
> I also recommend you get a
> router speed control from
> Harbor Freight and slow the cup
> a lot. I had one fragment, hit me
> in the knee and it was like being
> shot... I practically passed out
> from the pain so keep the speed
> low and use a light touch.
> Good Luck,
> Michael Wendt
> Wendt Pottery
> 2729 Clearwater Ave
> Lewiston, ID 83501
> USA
> 208-746-3724
> http://www.wendtpottery.com
> wendtpot@lewiston.com
> Paul wrote:
> I have a diamond cup grinder made by Pearl, a very
> heavy duty and expensive thing that I bought several
> years ago when I got a whole set of heavily used kiln
> shelves for free and they needed extensive work. But I
> have found that this grinder is not the best thing when
> you just want to remove all the kiln wash from a shelf
> and apply a fresh coat as it tends to cut into the
> shelf sometimes. What I need is a cup grinder just like
> the abrasive discs and cutting wheels used on angle
> grinders for grinding metal, except in a cup shape.
> Anyone know where the best place to get them is? I
> think I would use a 4 cup but use it on my 7" grinder
> since it would put a heavy load on the smaller one and
> the shafts are the same. I don't see these things at
> the home improvement places.
>
> Thanks,
>
> paul
>
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Vince Pitelka on tue 27 feb 07


Paul -
Go to www.grainger.com and enter 6A080 in the search box to access a 6"
silicon carbide cup stone that fits the standard 5/8x11 thread on angle
grinders - costs about $18 apiece, but they say that you have to buy a box
of five of them, so it would be about $90 - maybe you could split them with
another potter. As you point out, even this size of cup stone is a beast
and far too large for a small angle grinder. It requires a big heavy-duty
7" angle grinder. We've been using these cup stones to clean and level our
kiln shelves for ages. It will still dig into the shelf if you carelessly
bear down with the edge of the stone, but it is easier to control than
diamond media, because it's not removing material as quickly.

Like you, we recently purchased a very expensive diamond cup stone for
around $175. I had heard good things about them for particular
applications. We recently did refractory repairs on our salt kiln, and
needed to trim some bricks that were thoroughly glazed in place. That big
diamond cup stone on our 7" DeWalt angle grinder trimmed them like butter.
We probably would have gone through a whole new silicon carbide cup stone to
accomplish the same thing. With the diamond cup stone, you have to be very
careful not to apply too much pressure, because it will dig deep very
quickly. With the silicon carbide cup stone you can bear down on it a
little more forcefully and stay in control.
- Vince

Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/