vince pitelka on thu 25 jul 02
I received this message from someone who was hesitant to post to clayart
because of occasional rude responses, but I hope she will not mind if I post
the reply to the whole list, because I will be interested in feedback from
other people.
> >My kiln shelves are in dire need of cleaning: glaze runs; kiln wash
> >build-up etc. and hand tools won't do the trick.
> >I believe that a silicon carbide disk is needed. The disk is
> >attached to the grinder in the center. The disks I have seen are
> >thin and when they are attached the central bolt protrudes above the
> >surface of the disk.
> >It looks like the shield has to be removed also.
> >Isn't it the FACE of the disk which is applied to the shelf?
> >Are there specialized disks in which the attachment is recessed?
> >Where to get one? Home Depot doesn't have them.
Eleanor -
You should never hesitate to post questions to Clayart. If someone comes up
with a rude reply, remember that it is THEIR problem, not yours.
There are three primary kinds of grinding media for use on an angle grinder.
The most common are the sanding disk and the grinding disk. The sanding
disk is flexible, and has a flexible rubber or fiber back-up pad behind it.
It usually involves a flanged retainer nut in the center which holds the
replaceable disk in place. Sanding disks are not much good at all for
cleaning kiln shelves.
The grinding disk is a rigid fiberglass-reinforced disk, usually about 1/4"
thick. Sometimes they are completely flat, sometimes slightly cupped.
Sometimes they thread directly onto the grinder's spindle shaft, and
sometimes they attach with a flanged retainer nut which comes with the
grinder. Every Home Depot or Lowe's carries them. If the threaded spindle
is sticking out beyond the grinding disk, then you have the wrong disk for
your grinder. It is also possible that there is suppose to be a spacer on
the spindle behind the disk, and that has gotten misplaced. Take the angle
grinder in to Home Depot and have them help you select an appropriate
grinding disk.
If you are trying to level your shelf, use the flat surface of the grinding
disk. If you want to attack an especially troublesome glaze drip, use the
edge of the disk. You should not have to remove the guard. If you buy the
proper grinding disk, and if any intended spacer is in place behind the
disk, then the flat surface of the disk should stick up just beyond the
guard.
The third kind of grinding media is the cup-stone, which is essential for
very heavy-duty grinding on salt and wood kiln shelves, but cup stones are
normally only used on the big 7" and 9" angle grinders.
The hardest grinding disks are carborundum, and they work well on kiln
shelves. Nothing except diamond cutters will do a very good job of grinding
down into a silicon carbide kiln shelf, but you do not really want to do
that. All you want to do is level the shelf-wash and grind off any serious
glaze runs. You should be able to get a "masonry grade" grinding disk
especially designed for grinding bricks and other masonry, but you might
have to do some serious searching to find them for a small angle grinder.
In lieu of those, whatever rigid grinding disks are available at the
hardware store should work fine.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@worldnet.att.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Richard Aerni on fri 26 jul 02
I use a different grinding wheel than the ones Vince described in his post.
I tried the carbide ones, and the ones that are called grinding wheels, but
they had a negligible effect on my ash drips on cordierite shelves. What
works for me (and very quickly, I might add) is a diamond tipped grinding
wheel. It cost me about $40 for the 4" wheel, but has shown no wear and
tear after two years of use.
Richard Aerni
Bloomfield, NY
----- Original Message -----
From: "Rob Van Rens"
> If I may offer more advice on this subject;
>
> If you can't find the appropriate grinder disks at the Orange Store/Blue
> Store (Home Despot/Lowes), try the nearest W.W. Grainger outlet. Most
major
> urban areas have one...bring in your angle grinder and ask a clerk to help
> you find the one that fits.
>
Rob Van Rens on fri 26 jul 02
If I may offer more advice on this subject;
If you can't find the appropriate grinder disks at the Orange Store/Blue
Store (Home Despot/Lowes), try the nearest W.W. Grainger outlet. Most major
urban areas have one...bring in your angle grinder and ask a clerk to help
you find the one that fits.
If you've got an independent hardware store in your area, that's even
better. You know, an old, dusty place full of flannel-wearing guys, most of
whom seem to spend the majority of the day smoking and shirking work...but
they have every weird thing imaginable, like reverse-threaded metric
Whitworth machine screws. I used to work at such an establishment. Ah,
those were the days...
Robert Van Rens, Workshop Coordinator
Otto Kroeger Associates
703-591-6284, x110 Phone
703-591-8338 Fax
www.typetalk.com
Jim V Brooks on sat 27 jul 02
There will always be some glaze drips that have to be ground off. However,, i
have found that if i use an electric engraving tool.. it cuts right thru
the glaze..In most cases the glaze drips will pop off before i have completed
the process.
These engraving tool are available at home centers for under (or about)
$20.00 They have harden steel tips and they vibrate. I havent really
had to grind a shelf in years.. and i don't have chunks of shelves popping
off either. .
Jim in Denton
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