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Kiln Wash application-on a sunny day


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#1 Mark C.

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Posted 29 October 2012 - 10:28 PM

I have been putting off washing about 50 advancers (12x24s)

I fire them to cone 11 and my porcelain feet stick if not washed.

There are many ways to do this but this is what I have been doing for many years as far as washing shelves.

This will work with all types of shelves-advancers -mullite- corelite-dry pressed English-silicone carbide-whatever

There are many ways to apply wash brush -spray -roller. I like a heavy nap paint roller that leaves a nice stipple texture.

We are losing our heat with the sun getting lower and this job is easier if its sunny and warm .So today was sunny and warm so I did a dozen to get warmed up for big job in am.



First I grind the backs where any posts have left anything sticking up (yes I was my post tops and bottoms)

Then I flip the shelve and grind any rough or glazed areas and make them smooth. One can use a grinder-a carbide brick rasp-whatever. I choose to use a 4-inch Makita and a 7-inch Milwaukee sander with variable speeds.

I like to lay them out on ladders or anything waist high.

Get out your safety gea ras seen in photo-hard hat is handy for bear attacks as well and will protect you from falling tress and meteorites from space. Use the safety glasses andear muffs at least-keep lose clothing tucked in and read all the small print till you snap or go insane-do not wear a tie while grinding. Bow ties are ok.

I use an old bath mattor carpet or piece of rubber as a pad-make sure this cannot get into grinder.

If a grinder is too dangerous for you use masonry rubbing stone instead.

After grinding I lay them on a ladder and brush them off to remove the dust. Then let them heat up in sun.

I mix the wash like heavy cream and use a 5-gallon roller screen to remove excess wash from roller.

I roll on one thin coat and let dry in sun. Then when dry apply another really thin coat.

When dry I scrap the edges down with old knife but any tool will do. The wash tends to roll over the edges when applying and is an easy scrape at this point.

Then I stand the shelves on end wash-to-wash sides and when ready to load bisque fire I bisque them before glaze firing. With advancers you must go real slow as the wash got them wet and they need to dry slow other wise they can blow up. Never had this happen but know of it happing. Other shelves are less prone to this.

Here is the process in photos.

Mark



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Mark Cortright
www.liscomhillpottery.com

#2 TJR

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Posted 30 October 2012 - 08:32 AM

Mark;
I learned how to tie a bow tie when I was in Edmonton this week to accept my award. A woman at my table said; "You don't suit a bow tie." So I guess the only place I can wear it is when washing shelves. Once again, great photos, mate, and very informative.
TJR.

#3 Mark C.

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Posted 30 October 2012 - 02:19 PM

I almost forgot to mention a good dust mask. You will need one weather its a canister type or just a paper two band model. If the dust is thick I prefer my Kirby Morgan Band mask with alternative air supply. This setup requires a fellow diver I mean potter to help with getting it on or off. Either way use good safety gear.
Mark
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#4 bciskepottery

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Posted 30 October 2012 - 02:53 PM

After riding out the winds, rains, and cloudiness of Sandy the past couple of days, even the thought of grinding 50 shelves and applying kiln wash "on a sunny" day sounds envious.

#5 Mark C.

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Posted 30 October 2012 - 05:45 PM

One other note is about abrasives.
I have for years liked the masonry cup as seen on right on yard sale grinder.These are an easy way to remove any wash or whatever from a surface very fast. The middle 4 inch grinder also has a concrete disc and now I also use the diamond disc's as shown which are very useful as well. The 7 inch on the right has a masonry disc. I like a selection when grinding as the applications are different-glaze-wash or stilt chunks.
One last thing is these tools can hurt you bad so use them only after learning how to use them properly.
Mark

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#6 Samick FFP

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Posted 03 January 2013 - 05:02 PM

Hi Mark, you are on a subject most painful for me. Doing the kiln shelves is the worst job, and it never lasts more than one firing. Ocasionally a shelf will make it through s 2 firings, and I rejoice! I use a comercial wash, and have mixed to various consistencys. "cream" sums it up. Not rocket science, after all! So I start with nice clean, dust free shelves. :-) Carefully mixed wash :-) Thin coat, nice and even :-) Thuroughly dry. :-) Next day, recoat. I have tried up to 4 coats. They look terrific! Fire the kiln, either to 04 or 5, remove the pots, but once again the shelves are flaking. :-[ Been doing it just this way for YEARS! How is it that other potters have lovley built up coats and only have to apply an ocasional dab? And, before anyone mentions it, none of the potters I know has to put glue (an added expense) in their wash. What gives??

#7 Mark C.

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Posted 03 January 2013 - 09:57 PM

Hi Mark, you are on a subject most painful for me. Doing the kiln shelves is the worst job, and it never lasts more than one firing. Ocasionally a shelf will make it through s 2 firings, and I rejoice! I use a comercial wash, and have mixed to various consistencys. "cream" sums it up. Not rocket science, after all! So I start with nice clean, dust free shelves. :-) Carefully mixed wash :-) Thin coat, nice and even :-) Thuroughly dry. :-) Next day, recoat. I have tried up to 4 coats. They look terrific! Fire the kiln, either to 04 or 5, remove the pots, but once again the shelves are flaking. :-[ Been doing it just this way for YEARS! How is it that other potters have lovley built up coats and only have to apply an ocasional dab? And, before anyone mentions it, none of the potters I know has to put glue (an added expense) in their wash. What gives??


My guess is you whole problem is the commercial kiln wash-most I have seen is (how should I say this ) cheaply made.
Make your own-just look for the wash recipe thread last year for formulas-what temperature are you glaze firing to??
When you make your own wash it will stick better-do not build it up to thick-I was only every few years and it never flakes off
If you can warm the shelves in the sun first or let them sun dry and apply two coats total not 4
I can post my recipe again but its made for high fire as its got more alumina in it than low fire folks need.
Mark
Mark Cortright
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