Vince Pitelka on wed 19 jan 11
Laurie Hashizume wrote:
"If anyone is willing to explain exactly how one uses a grinder to remove
kiln wash from an entire shelf (including 24" round shelves) , I woud
appreciate it. A friend loaned me her grinder, and I couldn't figure out
how I might use it without gouging the shelves .... it had a big guard on
it with warnings not to remove
it, so the only part that could actually touch the shelf would be the edge.
I resorted to a small power sander, which worked fine but took an awfully
long time. I'm not "married" to using a grinder, so any other
suggestions would be welcome.
Hi Laurie -
The two most common attachments for the popular 4.5" angle grinders are the
rigid, fiberglass-reinforced grinding disk, and a flexible rubber or fiber
backup pad that takes sanding disks. The one you are talking about is the
grinding disk, and it is true that with the normal guard on you can only us=
e
the edge of the grinding disk. But if you have the flexible backing pad,
you can purchase disks in any grade of grit, and if you get one about
80-grit it will work great for sanding the wash off a kiln shelf, even with
the guard in place. As another option, if you get a 4" silicon carbide
cup-wheel, it will extend up just beyond the guard, and then you can use th=
e
flat surface of the cup-wheel with a delicate touch to level the surface of
the shelf, removing all wash. Some people still find the cup-wheel too
aggressive, and in that case the sanding disks will work better. If you
find the sanding disk too aggressive, you can just grind it against a brick
or rock briefly and it will tone down the grit a bit.
Someone else recommended wire cup-wheels, but I do not like to use them in
this application. I want a little grinding action, and I can get that with
the sanding disk. Also, the very worst thing about wire wheels is the way
they throw wires, sometimes when they are brand new, sometimes when they ge=
t
a little age on them.
If you are going to purchase an angle grinder, make sure to get one with a
5/8x11 thread on the arbor. That is the standard size that fits all of the
readily-available attachments. Also, there will be a limited assortment of
attachments available at Lowe's or Home Depot, but you might find a larger
assortment at a welding supply business.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
Laurie Hashizume on wed 19 jan 11
Sorry, I missed (inadvertently deleted) some of the posts about using a
grinder on kiln shelves. If anyone is willing to explain exactly how
one uses a grinder to remove kiln wash from an entire shelf (including
24" round shelves) , I woud appreciate it. A friend loaned me her
grinder, and I couldn't figure out how I might use it without gouging
the shelves .... it had a big guard on it with warnings not to remove
it, so the only part that could actually touch the shelf would be the
edge. I resorted to a small power sander, which worked fine but took an
awfully long time. I'm not "married" to using a grinder, so any other
suggestions would be welcome.
Thanks,
Laurie Hashizume
jonathan byler on wed 19 jan 11
for kiln wash alone, a wire wheel on the grinder tends to work
better. less damage to the shelf. makes a mess, though. buy an
american one, not the cheapy import ones that are never balanced well,
your hands will thank you.
On Jan 19, 2011, at 3:34 PM, Laurie Hashizume wrote:
> Sorry, I missed (inadvertently deleted) some of the posts about
> using a
> grinder on kiln shelves. If anyone is willing to explain exactly how
> one uses a grinder to remove kiln wash from an entire shelf (including
> 24" round shelves) , I woud appreciate it. A friend loaned me her
> grinder, and I couldn't figure out how I might use it without gouging
> the shelves .... it had a big guard on it with warnings not to remove
> it, so the only part that could actually touch the shelf would be the
> edge. I resorted to a small power sander, which worked fine but
> took an
> awfully long time. I'm not "married" to using a grinder, so any other
> suggestions would be welcome.
>
> Thanks,
>
> Laurie Hashizume
William & Susan Schran User on thu 20 jan 11
On 1/19/11 11:05 PM, "Vince Pitelka" wrote:
> If you are going to purchase an angle grinder, make sure to get one with =
a
> 5/8x11 thread on the arbor. That is the standard size that fits all of t=
he
> readily-available attachments. Also, there will be a limited assortment =
of
> attachments available at Lowe's or Home Depot, but you might find a large=
r
> assortment at a welding supply business.
I wanted to 2nd what Vince writes about angle grinders and the thin grindin=
g
disks. If you buy these disks at home centers, get the ones listed for
masonry. As the name implies, the tool is meant to be held at an angle when
using the thin disks. Unless you are very good at using the tool, it is ver=
y
easy to create deep gouges in cordierite/high alumina shelves while trying
to remove glaze. Using the flexible pad with SiC sanding disk will help wit=
h
this issue. As he wrote, a SiC cup will work flat, but you must take care t=
o
keep it flat, as it can also cut into the shelf if held at an angle.
For many minor glaze drips, the simplest may be a hand held, human powered
silicon carbide rubbing brick.
For the big job of removing build up of kiln wash on multiple shelves, a
silicon carbide belt fitted on a belt sander may be the fastest and easiest=
,
especially on cordierite shelves that are easily cut into. This is a nasty,
dusty job that MUST be done outside wearing all proper protective gear,
perhaps including a change of clothes close by.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
jonathan byler on thu 20 jan 11
You shouldn't have to worry about slowing the grinder down with a
speed control unless you like that it grinds less aggressively. When
I am doing this I want to get the job done, so full speed is better
IMHO. The wheels are not going to shatter and hurt you unless they
have been dropped or otherwise abused. Don't use the wheel if it is
chipped or otherwise damaged or if it vibrates excessively. Use them
only as directed on the package, don't get creative with them. it
sounds like the stories of wheels shattering have been from people
using the wrong wheel for the job or using it improperly. A standard
silicon carbide wheel for grinding masonry (made in usa, not cheapie
import) is not going to shatter from the work that you are doing
grinding kiln shelves. I have seen students perform all kinds of
abuse on these and I have never seen one come apart.
> The one you are talking about is the
> grinding disk, and it is true that with the normal guard on you can
> only use
> the edge of the grinding disk.
These grinding wheels are made to use at about a 15 degree angle to
the work. read the directions with the grinder and with the wheels if
you are unsure about how to use these. using them flat will wear the
wheel poorly and make it more likely to shatter. Don't do it. if
you want to grind flat, buy a cup wheel.
never exceed the max RPM that the wheel is rated for.
> Also, the very worst thing about wire wheels is the way
> they throw wires, sometimes when they are brand new, sometimes when
> they get
> a little age on them.
>
if you buy quality wheels they are less likely to throw wires out. if
you are having problems with this, where some gloves and a leather
apron to keep the wires from poking you. don't buy the cheapie import
ones even if you think they are the only option for you to purchase.
american made quality wheels are available buy from grainger or
mcmaster carr or some other reputable dealer. they will have good
ones. The wire wheels do not eat into the shelf in the way a sanding
disk will or a grinding wheel. all that comes off is the kiln wash,
no problem at all.
> If you are going to purchase an angle grinder, make sure to get one
> with a
> 5/8x11 thread on the arbor. That is the standard size that fits all
> of the
> readily-available attachments. Also, there will be a limited
> assortment of
> attachments available at Lowe's or Home Depot, but you might find a
> larger
> assortment at a welding supply business.
> - Vince
>
excellent advice. there are a number of them out there with metric
threads. these grinders are a little smaller and lighter, but you
will have a harder time finding wheels, etc.
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Tech University
> vpitelka@dtccom.net; wpitelka@tntech.edu
> http://iweb.tntech.edu/wpitelka
Vince Pitelka on fri 21 jan 11
Brandon Phillips wrote:
"I'm usually not one to quibble in such a large group(quibble being defined
as:A petty distinction or an irrelevant objection) but the name refers to
the head being at a 90 angle to the motor, in fact the original name for th=
e
tool is a right angle grinder."
Hi Brandon -
I am not sure that is what the person meant, but if it is, then you are
absolutely right. The name "angle grinder" is based on the fact that it ha=
s
a right-angle drive, and has nothing to do with how you hold the tool
against the work.
There is one kind of fiberglass-reinforced disk-wheel that has a slightly
cupped shape, and I am ashamed to say that back when I was employed as a
mechanic and welder for the City of Arcata in the 1970s, we called that
particular kind of wheel a "coolie-hat," which is of course based on the
derogatory reference to the Chinese on the West Coast in the 19th century,
and the shallow cone-shaped hats they wore. Those fiberglass-reinforced
disks, which were about 3/8" thick, are designed to be used at an angle.
Even the 3/8"-thick fiberglass-reinforced flat grinding disks available at
Lowe's, Home Depot, and the local welding supply shop are intended to be
used either on the edge or at an angle.
You wrote:
"I would take issue with holding the thin disks at an angle...unless it is =
a
90 degree angle. Holding them at anything but 90 and applying pressure can
cause them to buckle and shatter. I'm of course talking about those
1/16-1/8" cutting disks which is immediately what I think of when one says
thin disks. This may not be what you're referring to in which case disregar=
d
my objection."
I wondered about that too. The very thin ones, such are used on pneumatic
cutoff tools, should never be used with any side-pressure. When I hear
someone refer to a thin disk, that's what I think of. No side-pressure
should be applied unless the disk is at least 1/4" thick and preferably
3/8".
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
Steve Mills on fri 21 jan 11
As an addendum to Bill's post;
I use a disposable paper boiler-suit for that sort of work, in addition to =
a=3D
proper Respirator and Mask. Dust from cleaning shelves is pervasive and da=
n=3D
gerous, and gets deep into normal fabrics, and I find that the best way of =
e=3D
nsuring its safe disposal.
Steve M
Steve Mills
Bath
UK
Sent from my Itouch
On 20 Jan 2011, at 15:48, William & Susan Schran User wro=
t=3D
e:
>=3D20
> I wanted to 2nd what Vince writes about angle grinders and the thin grind=
i=3D
ng
> disks. If you buy these disks at home centers, get the ones listed for
> masonry. As the name implies, the tool is meant to be held at an angle wh=
e=3D
n
> using the thin disks. Unless you are very good at using the tool, it is v=
e=3D
ry
> easy to create deep gouges in cordierite/high alumina shelves while tryin=
g=3D
> to remove glaze. Using the flexible pad with SiC sanding disk will help w=
i=3D
th
> this issue. As he wrote, a SiC cup will work flat, but you must take care=
t=3D
o
> keep it flat, as it can also cut into the shelf if held at an angle.
>=3D20
> For many minor glaze drips, the simplest may be a hand held, human powere=
d=3D
> silicon carbide rubbing brick.
>=3D20
> For the big job of removing build up of kiln wash on multiple shelves, a
> silicon carbide belt fitted on a belt sander may be the fastest and easie=
s=3D
t,
> especially on cordierite shelves that are easily cut into. This is a nast=
y=3D
,
> dusty job that MUST be done outside wearing all proper protective gear,
> perhaps including a change of clothes close by.
>=3D20
> Bill
>=3D20
> --
> William "Bill" Schran
> wschran@cox.net
> wschran@nvcc.edu
> http://www.creativecreekartisans.com
Brandon Phillips on fri 21 jan 11
I realize this thread is dying if not dead but I just wanted to throw this
out there for anyone interested. I bought a 4.5" diamond cup wheel from
harbor freight today,(i'm broke and i had a coupon, what can you do?) I
am mostly pleased with it. It's not very well balanced and makes the
grinder vibrate something fierce(fine with gloves on) but it is a fairly
aggressive wheel. I fire in a wood/salt kiln so aggressive is what I
need. I have salted kiln wash that's been on my shelves for many firings,
it had fused and would not come off with my other wheel. This wheel took
it off no problem. Glaze drips grind right off with little pressure.
Strangely enough it did not dig in to the shelves as easy as the dewalt
that I typically use. I would not use these wheels for anything other
than silicon carbide shelves, they grind through corderite like a hot
knife through butter.
http://www.harborfreight.com/4-1-2-half-inch-diamond-turbo-cup-wheel-98729.=
html
The wheel in the photo looks used, thats harbor freight for you I guess.
>> As the name implies, the tool is meant to be held at an angle when
>> using the thin disks.
I'm usually not one to quibble in such a large group(quibble being defined
as:A petty distinction or an irrelevant objection) but the name refers to
the head being at a 90 angle to the motor, in fact the original name for
the tool is a right angle grinder.
I would take issue with holding the thin disks at an angle...unless it is
a 90 degree angle. Holding them at anything but 90 and applying pressure
can cause them to buckle and shatter. I'm of course talking about those
1/16-1/8" cutting disks which is immediately what I think of when one says
thin disks. This may not be what you're referring to in which case
disregard my objection.
Brandon Phillips
supportyourlocalpotter.blogspot.com
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