[Nelly]

Dear All,

In my 20 something years as a potter, I can tell you the number of times I have chipped off glaze from the shelf--exactly twice. One was that something dripped on someone else's pot and I had to do the clean and tonight, when I saw not one but three spots of hardened glaze on the exterior aspect of my large kiln shelf.

I have been taught to wear goggles and to chip at the glaze area with a hammer and chisel over water. This job tonight took me approximately 2 hours to gouge out the glaze.

Here were my methods after much frustration:

1. Hammer and chisel (brand new chisel used).

2. Brick (thinking I could use the abrasion of the brick to loosen the glaze)--nada!!!

3. Course sand paper.

4. Got out my dremmel.

5. Went back to the hammer and chisel and went from a 45 to more of a ninety degree angle.

This was laborious work. Elbow grease.

There has to be an easier way.

Know I usually have sand on my shelves and then cookies with kiln wash. Somehow the glaze escaped these precautionary pieces and ended up on the shelf.

After I got what I would say was 95% of the glaze out with some significant gouges, I put some kiln wash on these places and again rebaked the shelf on low for an hour or so. Soooooo much work.

Tell me there is a better way and I have missed it in all these years of potting.

How incredibly tiring and frustrating.

If anyone has any great suggestions, please let me know.

I am someone who is very cautious about the bottoms of my pieces. I wax at least a 1/4 of an inch up the pot. This was one from my recent party of kids that must have somehow snuck through and I didn't catch it or I misplaced the chips underneath.

Nelly

[JBaymore]

VERY simple solution.

4 1/2" angle grinder

4 1/2" diamond blade

High impact face shield

HEPA rated respirator that FITS

A location outside that the dust is not an issue, or a GOOD local pickup ventilation system

This works like a hot knife through butter. You have to watch out for quickly cutting INTO the kiln shelf, even silicon carbide. Cordierite and alumina shelves simply disappear under the blade. Takes seconds to remove even the worst drips and such. And no micro-crack starting vibrations from the hammer either. Use a diamond blade on the Dremel to finish up the fine work.

I'm a woodfirer... I LIVE by the diamond blade. Picture a noborigama load of shelves messed up with wood ash.

best,

...................john

[Nelly]

JBaymore, on 18 August 2012 - 07:42 PM, said:

VERY simple solution.

4 1/2" angle grinder

4 1/2" diamond blade

High impact face shield

HEPA rated respirator that FITS

A location outside that the dust is not an issue, or a GOOD local pickup ventilation system

This works like a hot knife through butter. You have to watch out for quickly cutting INTO the kiln shelf, even silicon carbide. Cordierite and alumina shelves simply disappear under the blade. Takes seconds to remove even the worst drips and such. And no micro-crack starting vibrations from the hammer either. Use a diamond blade on the Dremel to finish up the fine work.

I'm a woodfirer... I LIVE by the diamond blade. Picture a noborigama load of shelves messed up with wood ash.

best,

...................john

[Nelly]

Nelly, on 18 August 2012 - 07:58 PM, said:

JBaymore, on 18 August 2012 - 07:42 PM, said:

VERY simple solution.

4 1/2" angle grinder

4 1/2" diamond blade

High impact face shield

HEPA rated respirator that FITS

A location outside that the dust is not an issue, or a GOOD local pickup ventilation system

This works like a hot knife through butter. You have to watch out for quickly cutting INTO the kiln shelf, even silicon carbide. Cordierite and alumina shelves simply disappear under the blade. Takes seconds to remove even the worst drips and such. And no micro-crack starting vibrations from the hammer either. Use a diamond blade on the Dremel to finish up the fine work.

I'm a woodfirer... I LIVE by the diamond blade. Picture a noborigama load of shelves messed up with wood ash.

best,

...................john

Dear John,

Thank you for your prompt reply. Can I get an angle grinder at the local hardware store as well as the diamond blade? I will definitely have this on hand in case this happens again. Darn near took me 2 hours and I could have been working.

The respirator part I did forget. Good point in mentioning that.

While now covered with kiln wash, my guess is that I still run the risk of some of the molton glass coming through if I didn't get it all. I will ensure this is a bottom shelf and place cookies over these spots that hopefully will not stick.

Do people ever turn their shelves over and use the clean side as they come to the end of their life span?? Part of me thinks yes (i.e., with careful removal of as much wash as possible and another part says absolutely not). You run the risk of kiln wash still being present and ruining your bisque or glaze ware.

Anyway, thanks for the suggestion. I will look up this angle grinder and see what I can find.

Thank you again.

Nelly

[JBaymore]

Nelly, on 18 August 2012 - 09:04 PM, said:

Nelly, on 18 August 2012 - 07:58 PM, said:

JBaymore, on 18 August 2012 - 07:42 PM, said:

VERY simple solution.

4 1/2" angle grinder

4 1/2" diamond blade

High impact face shield

HEPA rated respirator that FITS

A location outside that the dust is not an issue, or a GOOD local pickup ventilation system

This works like a hot knife through butter. You have to watch out for quickly cutting INTO the kiln shelf, even silicon carbide. Cordierite and alumina shelves simply disappear under the blade. Takes seconds to remove even the worst drips and such. And no micro-crack starting vibrations from the hammer either. Use a diamond blade on the Dremel to finish up the fine work.

I'm a woodfirer... I LIVE by the diamond blade. Picture a noborigama load of shelves messed up with wood ash.

best,

...................john

Dear John,

Thank you for your prompt reply. Can I get an angle grinder at the local hardware store as well as the diamond blade? I will definitely have this on hand in case this happens again. Darn near took me 2 hours and I could have been working.

The respirator part I did forget. Good point in mentioning that.

While now covered with kiln wash, my guess is that I still run the risk of some of the molton glass coming through if I didn't get it all. I will ensure this is a bottom shelf and place cookies over these spots that hopefully will not stick.

Do people ever turn their shelves over and use the clean side as they come to the end of their life span?? Part of me thinks yes (i.e., with careful removal of as much wash as possible and another part says absolutely not). You run the risk of kiln wash still being present and ruining your bisque or glaze ware.

Anyway, thanks for the suggestion. I will look up this angle grinder and see what I can find.

Thank you again.

Nelly

Nelly,

A good harware store, Lowes, Home Depot, or Harbour Freight Tools will have them.

You can heave you shelves cleaned of all kiln wash by taking them to a commercial sandblaster and ask them to remove all the white stuff down to the (whatever color) shelf surface. They have the right tool for the job and you don't get exposed to all the dust.

best,

.................john

[Marcia Selsor]

I got a great deal on 4 1/2" diamond blades and turbo cups for about $5 each for my angle grinder on eBay. They work like a charm. Saved me lots of time cleaning up the 48 kiln shelves at the end of the semester. I wanted the shop in good shape for the next teacher coming in. So I made sure every kiln shelf was clean and rewashed. The diamond discs were mine but I donated one to the cause to clean the shelves. I got four in a bundle. One was all I needed for the job and it is still fine. Gave one to the sculpture dept. and left one in the Ceramics dept.

marcia

[Mark McCombs]

JBaymore, on 18 August 2012 - 05:42 PM, said:

4 1/2" diamond blade

That's the part I needed to know.



Thanks, John.

[yedrow]

Out of curiosity how much are diamond blades. I use a masonry disc, cup style. I think it's silicon carbide and I can get them for about $35. The cut through glaze pretty fast, but I've only used on on advancers so I don't know how nasty they would get on a cordieritte shelf.

[LilyT]

yedrow, on 18 August 2012 - 09:42 PM, said:

Out of curiosity how much are diamond blades. I use a masonry disc, cup style. I think it's silicon carbide and I can get them for about $35. The cut through glaze pretty fast, but I've only used on on advancers so I don't know how nasty they would get on a cordieritte shelf.

Mine was $15, but I've seen them for less on line ($7). I hear that you pay for the actual
amount of cutting surface (ie diamond tips). Make sure you keep it cool while using
it or it will go smooth pretty quickly. If you use water to cool the cut, watch out
for electric shock hazards. They are pretty sweet to use.

[JBaymore]

yedrow, on 19 August 2012 - 12:42 AM, said:

Out of curiosity how much are diamond blades. I use a masonry disc, cup style. I think it's silicon carbide and I can get them for about $35. The cut through glaze pretty fast, but I've only used on on advancers so I don't know how nasty they would get on a cordieritte shelf.

Compared to a "masonry disc" this is a Japanese katana versus a butter knife.

I don't think I have paid more than what you are mentioning there for the masonry disc (sounds overpriced?).... and I tend to buy the top quality ones... rather than the Harbour Freight type ones.



And yes...... they can dig into Advancers and Crystars also.

best,

.............john

[Karen B]

Nelly, on 18 August 2012 - 08:04 PM, said:

Nelly, on 18 August 2012 - 07:58 PM, said:

JBaymore, on 18 August 2012 - 07:42 PM, said:

VERY simple solution.

4 1/2" angle grinder

4 1/2" diamond blade

High impact face shield

HEPA rated respirator that FITS

A location outside that the dust is not an issue, or a GOOD local pickup ventilation system

This works like a hot knife through butter. You have to watch out for quickly cutting INTO the kiln shelf, even silicon carbide. Cordierite and alumina shelves simply disappear under the blade. Takes seconds to remove even the worst drips and such. And no micro-crack starting vibrations from the hammer either. Use a diamond blade on the Dremel to finish up the fine work.

I'm a woodfirer... I LIVE by the diamond blade. Picture a noborigama load of shelves messed up with wood ash.

best,

...................john

Dear John,

Thank you for your prompt reply. Can I get an angle grinder at the local hardware store as well as the diamond blade? I will definitely have this on hand in case this happens again. Darn near took me 2 hours and I could have been working.

The respirator part I did forget. Good point in mentioning that.

While now covered with kiln wash, my guess is that I still run the risk of some of the molton glass coming through if I didn't get it all. I will ensure this is a bottom shelf and place cookies over these spots that hopefully will not stick.

Do people ever turn their shelves over and use the clean side as they come to the end of their life span?? Part of me thinks yes (i.e., with careful removal of as much wash as possible and another part says absolutely not). You run the risk of kiln wash still being present and ruining your bisque or glaze ware.

Anyway, thanks for the suggestion. I will look up this angle grinder and see what I can find.

Thank you again.

Nelly

Nelly, I turn my shelves over as they sag if always used on one side.

[Nelly]

Karen B, on 19 August 2012 - 01:16 PM, said:

Nelly, on 18 August 2012 - 08:04 PM, said:

Nelly, on 18 August 2012 - 07:58 PM, said:

JBaymore, on 18 August 2012 - 07:42 PM, said:

VERY simple solution.

4 1/2" angle grinder

4 1/2" diamond blade

High impact face shield

HEPA rated respirator that FITS

A location outside that the dust is not an issue, or a GOOD local pickup ventilation system

This works like a hot knife through butter. You have to watch out for quickly cutting INTO the kiln shelf, even silicon carbide. Cordierite and alumina shelves simply disappear under the blade. Takes seconds to remove even the worst drips and such. And no micro-crack starting vibrations from the hammer either. Use a diamond blade on the Dremel to finish up the fine work.

I'm a woodfirer... I LIVE by the diamond blade. Picture a noborigama load of shelves messed up with wood ash.

best,

...................john

Dear John,

Thank you for your prompt reply. Can I get an angle grinder at the local hardware store as well as the diamond blade? I will definitely have this on hand in case this happens again. Darn near took me 2 hours and I could have been working.

The respirator part I did forget. Good point in mentioning that.

While now covered with kiln wash, my guess is that I still run the risk of some of the molton glass coming through if I didn't get it all. I will ensure this is a bottom shelf and place cookies over these spots that hopefully will not stick.

Do people ever turn their shelves over and use the clean side as they come to the end of their life span?? Part of me thinks yes (i.e., with careful removal of as much wash as possible and another part says absolutely not). You run the risk of kiln wash still being present and ruining your bisque or glaze ware.

Anyway, thanks for the suggestion. I will look up this angle grinder and see what I can find.

Thank you again.

Nelly

Nelly, I turn my shelves over as they sag if always used on one side.

[Nelly]

Nelly, on 19 August 2012 - 03:28 PM, said:

Karen B, on 19 August 2012 - 01:16 PM, said:

Nelly, on 18 August 2012 - 08:04 PM, said:

Nelly, on 18 August 2012 - 07:58 PM, said:

JBaymore, on 18 August 2012 - 07:42 PM, said:

VERY simple solution.

4 1/2" angle grinder

4 1/2" diamond blade

High impact face shield

HEPA rated respirator that FITS

A location outside that the dust is not an issue, or a GOOD local pickup ventilation system

This works like a hot knife through butter. You have to watch out for quickly cutting INTO the kiln shelf, even silicon carbide. Cordierite and alumina shelves simply disappear under the blade. Takes seconds to remove even the worst drips and such. And no micro-crack starting vibrations from the hammer either. Use a diamond blade on the Dremel to finish up the fine work.

I'm a woodfirer... I LIVE by the diamond blade. Picture a noborigama load of shelves messed up with wood ash.

best,

...................john

Dear John,

Thank you for your prompt reply. Can I get an angle grinder at the local hardware store as well as the diamond blade? I will definitely have this on hand in case this happens again. Darn near took me 2 hours and I could have been working.

The respirator part I did forget. Good point in mentioning that.

While now covered with kiln wash, my guess is that I still run the risk of some of the molton glass coming through if I didn't get it all. I will ensure this is a bottom shelf and place cookies over these spots that hopefully will not stick.

Do people ever turn their shelves over and use the clean side as they come to the end of their life span?? Part of me thinks yes (i.e., with careful removal of as much wash as possible and another part says absolutely not). You run the risk of kiln wash still being present and ruining your bisque or glaze ware.

Anyway, thanks for the suggestion. I will look up this angle grinder and see what I can find.

Thank you again.

Nelly

Nelly, I turn my shelves over as they sag if always used on one side.

But what about the remaining kiln wash on the lower part of the shelf? Will it not flake off and will I run the risk of damaging future glaze work?

At this point, my kiln wash is not taking. I am thinking about John's suggestion of sandblasting the shelf. I will check and see the cost.

I will invest in the grinder. I have located one that I think will be just fine at our local Canadian Tire. I will also check out Home Depot and Rona.

But do tell me, can I simply turn the shelf over and use this as a new flat surface with kiln wash on the top?

I remember a fight breaking out in my old studio where one member kept flipping the shelves and using the flat side without kiln wash. Everyone was up in arms about this occurring. Thus, I have been reluctant to do this thinking I may send chips flying into my ware.

Maybe it is simply an issue of making sure all loose wash is removed to the best of my ability and then flipping it over, rewashing the surface and I will be good to go.

But in the future, I will have the grinder to get off the glaze chunks. I keep hearing in my mind the grinder "cuts like butter" and comparing it to the work I did yesterday to get these big blotches of glaze off the shelves.

Nelly

[Darla]

I posted this a few months ago..... I can't describe how much easier this is. I've been able to clean my shelves completely of kiln wash and glaze, turn them as has been suggested with no issues. I think my husbands angle air grinder is from sears, probably from 20 plus years ago, but I've seen inexpensive ones advertised for $25. On top of all of this, since the air grinder takes its power from the air compressor, there is no motor on the grinder itself, so it weighs a ton less than a regular grinder.

Recently, my husband needed something from me, and came into the barn while I was trying to clean my shelves. Gave me this look of "you're doing that wrong", took the shelf and came back about ten minutes later - with it perfectly bare. No glaze, no kiln wash, no flakes, and NO chunks out the shelf. I, of course, took full advantage, and begged for him to do the rest. Less than 40 minutes later, every shelf I own was clean! He had taken the shelves out to his workshop, where he used an air grinder/compressor and a 'flex disc 36 grit'. Its designed to be used on Auto Body work. If you already have an air compressor for spraying or such, the air grinder and the flex discs are fairly inexpensive. (Please use safety gear!)

[WillowTreePottery]

Interesting about the compressor, I must remember that. What psi would be needed?

[Darla]

WillowTreePottery, on 19 August 2012 - 05:20 PM, said:

Interesting about the compressor, I must remember that. What psi would be needed?

I had to ask. ;-) Between 80 and 100.

[LilyT]

Darla, on 19 August 2012 - 02:37 PM, said:

I posted this a few months ago..... I can't describe how much easier this is. I've been able to clean my shelves completely of kiln wash and glaze, turn them as has been suggested with no issues. I think my husbands angle air grinder is from sears, probably from 20 plus years ago, but I've seen inexpensive ones advertised for $25. On top of all of this, since the air grinder takes its power from the air compressor, there is no motor on the grinder itself, so it weighs a ton less than a regular grinder.

Recently, my husband needed something from me, and came into the barn while I was trying to clean my shelves. Gave me this look of "you're doing that wrong", took the shelf and came back about ten minutes later - with it perfectly bare. No glaze, no kiln wash, no flakes, and NO chunks out the shelf. I, of course, took full advantage, and begged for him to do the rest. Less than 40 minutes later, every shelf I own was clean! He had taken the shelves out to his workshop, where he used an air grinder/compressor and a 'flex disc 36 grit'. Its designed to be used on Auto Body work. If you already have an air compressor for spraying or such, the air grinder and the flex discs are fairly inexpensive. (Please use safety gear!)

that's a great idea! (and yes, please do this outdoors and with respirator, because it will put that dust
(epk has silica, and alumina is just plain harsh and irritating due to it's shape) into your workshop or garage
everywhere forever.)

angle grinders are inexpensive, easy to use. some of them are less reliable than others - we went
through a shocking number of them one summer and thought it was due to dust intake heating
up the motor (I think that's a known problem) but no, some of them had developed electrical problems
and were too cheap to fix so just replaced. They are full of really cool mechanical parts for those
of you inclined to play with such things. Made me want to do something sculptural with the pretty pieces.

[Nelly]

WillowTreePottery, on 19 August 2012 - 06:20 PM, said:

Interesting about the compressor, I must remember that. What psi would be needed?

I agree, that is interesting. I too must remember that.

Nancy

[LilyT]

Darla, on 19 August 2012 - 02:37 PM, said:

I posted this a few months ago..... I can't describe how much easier this is. I've been able to clean my shelves completely of kiln wash and glaze, turn them as has been suggested with no issues. I think my husbands angle air grinder is from sears, probably from 20 plus years ago, but I've seen inexpensive ones advertised for $25. On top of all of this, since the air grinder takes its power from the air compressor, there is no motor on the grinder itself, so it weighs a ton less than a regular grinder.

Recently, my husband needed something from me, and came into the barn while I was trying to clean my shelves. Gave me this look of "you're doing that wrong", took the shelf and came back about ten minutes later - with it perfectly bare. No glaze, no kiln wash, no flakes, and NO chunks out the shelf. I, of course, took full advantage, and begged for him to do the rest. Less than 40 minutes later, every shelf I own was clean! He had taken the shelves out to his workshop, where he used an air grinder/compressor and a 'flex disc 36 grit'. Its designed to be used on Auto Body work. If you already have an air compressor for spraying or such, the air grinder and the flex discs are fairly inexpensive. (Please use safety gear!)

Darla, would you ask your husband what's the brand and exact name of the item he uses? I tried googling
flex disc 36 grit and got a variety of hits, so am not sure which one it is? And also does he use some
sort of pad or backing device for it? Thanks for your help, and sharing this great idea!

Warmly,
Lily

[Mark C.]

Advancer shelve do not suck up glaze and it comes right off. just tap it-there are what I use 100% now but when I use= dry pressed english shelve in slat I like the 4 inch grinder with diamond or masonry blades. The cordite and mullite shelves suck up glaze and need to be ground out.
If you have a lot of them move up to a 9 inch Milwaukee grinder with a silicone carbide cup head but be aware this tool can hurt you and needs respect.
All of these need safety gear.
Mark