docweathers Posted February 10, 2015 Report Share Posted February 10, 2015 I was having trouble with kiln wash flaking off of my shelves. To try to solve this I wash my shelves thoroughly to got all of the old kiln wash off. When they were dry, I brushed on three layers of Laguna's premium kiln wash, painting each layer in the crosswise direction of the previous layer. After they dried thoroughly I did a cone 6 glaze firing. Now my kiln wash is flaking off even worse. what am I doing wrong? Link to comment Share on other sites More sharing options...
Mark C. Posted February 10, 2015 Report Share Posted February 10, 2015 I Never use a store bought wash There has been so many wash topics this past year. Search the archives I suggest starting over after you get that wash off with a good homemade wash-My guess is it either to thick or cheap ingredients or both-just my option -Does that wash have an ingredients list? I roll on two thin coats with paint roller myself I can go look up my wash formula in the studio in am if you cannot find those threads? Mark Link to comment Share on other sites More sharing options...
TJR Posted February 10, 2015 Report Share Posted February 10, 2015 Mark is correct as usual. Your wash may have a cheap filler in it such as ball clay which will shrink and peal off. A good wash is; Alumina hydrate 50% EPK 50% I apply my wash extremely thinly , like skim milk. TJR. Link to comment Share on other sites More sharing options...
Pres Posted February 10, 2015 Report Share Posted February 10, 2015 Unlike the others, I have been using a commercial wash, as I was not as savvy as I have become now. However, I do apply 3 skim milk thickness coats in cross painting and have no peeling. I think thickness of application is one of the biggest problems with most kiln washes. I used to not use it because I remembered seeing poorly washed shelves(thick layers) that would leave pieces on pots after firing. Somewhere in the 70's I was at a college conference that had a kiln loading with shelf wash before hand. I learned the correct way, and have done it ever since. Link to comment Share on other sites More sharing options...
neilestrick Posted February 10, 2015 Report Share Posted February 10, 2015 If you want the wash to actually catch glaze drips, you need to put it on thick enough to do the job. To get it that thick without flaking, it cannot have a high raw clay content like 50%. The raw clay content should be kept around 15%, enough to keep it suspended and brushable, but not so much that it shrinks a lot and flakes. You can have 50% total clay, but the remaining 35% needs to be calcined. I use: 1 scoop EPK 1 scoop Calcined EPK 2 scoops Flint 2 scoops Alumina Hydrate Link to comment Share on other sites More sharing options...
docweathers Posted February 10, 2015 Author Report Share Posted February 10, 2015 thanks for all the great information on kiln wash. I need a really bulletproof kiln wash since I'm still at the stage of testing many new glazes every time I fire. I thought the premium version of a brand name kiln wash, like Laguna, would be a safe bet. I should smarten up since I have had serious trouble with a number of their products. Which is more bulletproof, Neil or TJR's formula? I'm tired of taking pots and test tiles off of my shelves with a cold chisel. Link to comment Share on other sites More sharing options...
Mark C. Posted February 10, 2015 Report Share Posted February 10, 2015 Doc mine is Alumina hydrate 50% EPK 25% calcined epk 25% You could up the calcined amount as well. I apply it as a cream consistency with a paint roller with a roller with a drip expanded metel tray hanging in 5 gallon bucket. I load it up and roll the shelve with two passes to cover a 12x 24-let it sun dry and apply another coat. fire with bisque pots on it in bisque load then high fire with pots on it as well. this wash has worked well on all types of shelves over many decades. Never used commercial wash but have a bag that was given to me if you need it??I treat it as bad JUJU-hey maybe caulking a football or baseball field would be a good use of it. mark Link to comment Share on other sites More sharing options...
docweathers Posted February 10, 2015 Author Report Share Posted February 10, 2015 Thanks Marc Thats what I will be using, How hot/long do you have to heat EPK to calcinate it? Link to comment Share on other sites More sharing options...
TJR Posted February 10, 2015 Report Share Posted February 10, 2015 thanks for all the great information on kiln wash. I need a really bulletproof kiln wash since I'm still at the stage of testing many new glazes every time I fire. I thought the premium version of a brand name kiln wash, like Laguna, would be a safe bet. I should smarten up since I have had serious trouble with a number of their products. Which is more bulletproof, Neil or TJR's formula? I'm tired of taking pots and test tiles off of my shelves with a cold chisel. Doc and Neil; I am going to try to reply to both of you at the same time. A cheap wash we used in art school was 50 flint ,50 EPK. Neil recipe is good, so I demur to him. Alumina hydrate is expensive. you wouldn't use flint if you are salt firing. I don't have calcined clay on hand, but that is probably the best solution. TJR. Stick broken kiln shelves under your pots or bisque tiles until you get the running solved. T Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted February 11, 2015 Report Share Posted February 11, 2015 Thanks Marc Thats what I will be using, How hot/long do you have to heat EPK to calcinate it? Put some in a bowl in your next bisque fire. You don't need to do any special firing for it. Link to comment Share on other sites More sharing options...
rakukuku Posted February 11, 2015 Report Share Posted February 11, 2015 Good topic. On this note, is there a different type of kiln wash thats better for raku? I use the same as we use in the high fire but its time to scrape the raku base and re-wash it. Just wondered if one recipie is better than another. NOt even sure what we use in the highfire but we mix it ourselves. Rakuku Link to comment Share on other sites More sharing options...
neilestrick Posted February 11, 2015 Report Share Posted February 11, 2015 Good topic. On this note, is there a different type of kiln wash thats better for raku? I use the same as we use in the high fire but its time to scrape the raku base and re-wash it. Just wondered if one recipie is better than another. NOt even sure what we use in the highfire but we mix it ourselves. Rakuku High fire wash will work fine. When I raku fire I put each pot on top of a little piece of soft brick. It saves the shelf, but more importantly, I replace each piece of soft brick with a cool one for each firing so that the new batch of pots don't go on to a hot shelf and thermal shock them into cracking before the kiln is even closed up. Pots get pulled, soft brick pieces get pulled, cool soft bricks go in, pots go in. Fire and repeat. Link to comment Share on other sites More sharing options...
rakukuku Posted February 11, 2015 Report Share Posted February 11, 2015 good idea. we have several people using our raku kiln so there are globs of stuff on it from time to time. and its too hot to re scrape it so its always "later" which never happens. we should always use little broken shelves or unclaimed bisque pots at goo catchers. rakuku Link to comment Share on other sites More sharing options...
hitchmss Posted February 11, 2015 Report Share Posted February 11, 2015 I use a kiln wash that used/is to be used in Homer Laughlin factory. I believe I picked this info up from John Britt a while back. The issue with most kiln washes is that they have a tendency to be too soft and flake off too easily. You want a wash that will catch, and absorb the glaze run so it doesnt damage furniture, but also bonds with the shelf enough that it wont fall off constantly. I like to keep a thick (almost 3/8") layer of wash over my shelves. I used to use a 50/50 epk/alum mixture but found that the slightest nudge would chunk off big pieces of the kiln wash. This recipe uses a SMALL amount of G200 feldspar to help bind the wash to itself, and the shelf. Homer Laughlin did the tests; their method was to continue to increase the amount of g200 until they could no longer scratch/dent the wash with their fingernail. Heres the recipe we use: Calcined EPK-25% EPK- 25% Alumina Hydrate 50% G200- 1.75% We fire to cone 12, using mainly bmix as our clay. Here and there we have some issues with the kiln wash fusing with the foot rings, but a couple of quick passes with sandpaper knocks them loose. Porcelains and other high fluxing clay bodies have slightly more bond with the wash, but never requires the use of power tools to clean up.The wash binds well with our cordierite shelves and does a good job of catching glaze runs. If we have a run where we lose a big patch of wash off the shelf I have no problems with laying in a thick coat to fill the void. I find my first coat of kiln wash on brand new shelves should be a little thinner (heavy cream consistency) and only 2-3 coats. After the first base layer I'll build up coats every firing until I have that 3/8-1/2". Its a pain to lose all the space in the kiln for wash/shelves but its better than having to grind and replace shelves every month, and cheaper than advancers. If its cracking too much you can increase the % of calcined kaolin. I would not use this mix for a salt/soda kiln or a wood kiln; the added flux in the atmosphere and wash would likely cause bonding issues. Link to comment Share on other sites More sharing options...
Crusty Posted February 18, 2015 Report Share Posted February 18, 2015 Good post, Thanks for the recipe's every one.. I am having the same trouble with different com. washes.. I have tried it thin, thick, medium consistency and it all flaked on me... I have had it drop off in and on pots, it will drive you crazy... Somebody goofed up on a massive batch because that is all I have seen online, ahhh my wash is cracking and falling off... I feel I got ripped off more than once... I will try one of these recipe's very soon... Link to comment Share on other sites More sharing options...
Amy Eberhardt Posted February 18, 2015 Report Share Posted February 18, 2015 Dang guys! You're giving me the willies as I near my first glaze firing. I purchased a [somewhat] locally produced kiln wash at my last visit to Clay Art Center, as I don't have the first clue about making my own. Now I'm wondering if I'm going to be having some of the problems that others have had. Are these issues to be found in ALL commercially produced kiln wash recipes? Or is it limited to just a few? And since this will be my first glaze firing, perhaps you all will indulge me in a bit more information for the newb....... 1) How long do I let each coat dry before application of the next coat? 2) How long after the third coat has been applied do I need to wait before loading the kiln and firing it up? Minutes? Hours? Days? Inquiring minds need to know! Link to comment Share on other sites More sharing options...
Mark C. Posted February 18, 2015 Report Share Posted February 18, 2015 Dang guys! You're giving me the willies as I near my first glaze firing. I purchased a [somewhat] locally produced kiln wash at my last visit to Clay Art Center, as I don't have the first clue about making my own. Now I'm wondering if I'm going to be having some of the problems that others have had. Are these issues to be found in ALL commercially produced kiln wash recipes? Or is it limited to just a few? And since this will be my first glaze firing, perhaps you all will indulge me in a bit more information for the newb....... 1) How long do I let each coat dry before application of the next coat? 2) How long after the third coat has been applied do I need to wait before loading the kiln and firing it up? Minutes? Hours? Days? Inquiring minds need to know! I would not waste my time whith commmercially made wash unless you are a low fire artist. You let the 1st coat dry until its totally dry than a second coat-I use a paint roller myself. I do not use 3 coats but if you do make sure your wash is very thin as it will crack if thick.-Let the wash dry and fire a bit slower on 1st time up until any steam is gone then let it fly. Mark Link to comment Share on other sites More sharing options...
elaine clapper Posted February 18, 2015 Report Share Posted February 18, 2015 I use a commercial kiln was from Columbus Clay. I did have problems with it flaking until I realized I was applying it too think. I apply it with a sponge. Skim milk seems like to right consistency to me. Over the years I have also learned to make sure to keep it off the edges because if it is going to flake that creates the worst problem. Link to comment Share on other sites More sharing options...
Mark C. Posted February 18, 2015 Report Share Posted February 18, 2015 After your wash drys scrap all edges of shelves with knife or putty knife to butter knife to get all drips off the edges-do this before firing it . It comes right off at this state. Mark Link to comment Share on other sites More sharing options...
j e manning Posted April 3, 2015 Report Share Posted April 3, 2015 Something I'm not seeing here is water content. Just like a glaze cracking and peeling from a high water content so can kiln wash. Try the different than washes to find what suits your needs best but I'd advise a defloculant such as a bit of darvan to reduce the water and correspondingly the drying shrinkage as well... No drying shrinkage no cracking, no cracking no flaking. Good luck. Link to comment Share on other sites More sharing options...
curt Posted April 3, 2015 Report Share Posted April 3, 2015 Interesting. The kiln wash we use has a lot more alumina hydrate say 70% or 75%, and correspondingly less kaolin. I guess it is really the alumina hydrate that is doing the heavy lifting in terms of protecting the shelves. The clay is just there to facilitate application? I guess this may be why we have never really seen kiln wash cracking on the shelves, ie because we don't use that much clay in the kiln wash as people are talking about here? We put it on thick but I realise reading these posts that what "style" of kiln wash you use probably depends on your studio setting. In classroom settings with beginners who may quintuple dip when you aren't looking, or where you are experimenting with new glazes which might run a lot, better to have a generously thick sacrificial layer. This may prevent your kiln technician quitting in disgust after angle grinding too many shelves. Downside is that after repeated applications the shelves can become rough and uneven. Since much student work tends to be doorstop calibre this may not matter because it is unlikely to warp. Don't put your big fancy bowls on those shelves though or you will get some major league distortion on the rims! I like the idea of applying the skim milk layer, particularly when you can be reasonably confident your glazes are not going to run and all you need is a thin layer of ball bearings under your pot to prevent clay flaking during the firing as it sticks to the shelf then shrinks ( I forget right now what this called but it does have a name) Link to comment Share on other sites More sharing options...
Chantay Posted April 7, 2015 Report Share Posted April 7, 2015 When I am testing new glazes or combinations I use a sacraficel drip tray. Better than grinding shelves. Link to comment Share on other sites More sharing options...
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