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docweathers

Getting High Magnesium Glazes To Stick On Vertical Surfaces.

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docweathers    79

I am having trouble getting high magnesium glazes like Lalone crawl to stick on vertical surfaces. I have tried spraying over it with spray starch and hairspray. Does not work.

 

I have mixed Elmer's glue with it. This will cause it to stick but it changes the crackly character in ways I don't like. I have tried spraying a layer of Elmer's glue on and then spraying crawl over it. That doesn't work.

 

I emailed Mike Lalone because he has obviously figured out how to make it stick on vertical surfaces. I never got a reply

 

Often I resort to gluing the potato chips that have fallen off back on with a dab of Elmer's glue. This is a very crude solution which is very time-consuming.

 

Does anyone have a better idea?

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glazenerd    816

Neil:

I find myself in an unusual position. I cannot really say much in the forum these days. The potters here talk about the pieces they make and sell, and I make the clay and other products. If I posted the product, I would be in trouble for hawking. If I pulled my post to avoid the situation, I would hear about that too. Proprietary formula, cannot do that either. Probably would have been wiser not to answer at all.

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GEP    863

nerd, you are not in an unusual position. You could have used the PM function to provide your answer to docweathers.

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glazenerd    816

Mea: I had exactly that thought, after I made the post. If Neil had not responded, would have just pulled it down. Useless post.

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glazenerd    816

So Doc:

Back to your topic. At what cone are you bisqing to? Still using B- mix? What % of magnesium ( dry weight)?

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glazenerd    816

No wonder you have a flaky biscuit. Ball clay will not do much good unless it is above 11 CEC. None of the ball clays sold in the pottery market runs above 9: most average 7. Once any clay reaches 11 or above; it is then classified as a swelling clay. Bentones can run anywhere from 50-150, but they have the opposite problem of absorbing too much water. Fortunately for you.......

 

Nerd

 

Edit note: fortunately for you I have those ingredients out there, so I can run the test myself. Wanted to double check my mgo carb before I made that assertion.

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glazenerd    816

Doc."..your solution is:

 

Mix one tablespoon of white vinegar to one cup of water in a used plastic water bottle: marked crawl glaze water.

 

Your glaze with straight water is 9.78 PH..anytime a glaze crosses over the 9 mark, the flakier it will get. General rule of thumb to remember: high PH equals higher dehydration.

 

Your glaze mixed with crawl water: 8.42PH. You can add 2 tablespoons per cup if you want, but use your ph meter to get into the 8 PH range.

 

Add 10% OM4 ball clay to help hold water in the glaze.

Dunk your bisq piece in water (quickly) to stop it from pulling the water out of the glaze.

 

Now your glaze does not flake, however it will powder very easily. I rubbed the brush marks off with my hand in fact. So place the glazed pieces into the kiln immediately after glazing, handle as little as possible.

You also want to glaze fire as soon as possible because Nep Sy has 14-20% soluble salts that will begin migrating in a short period.

 

Rule of thumb in all glazes: the higher the PH, the faster it will dry, and more prone to flaking. How sodium silicate works in part: high PH applied to much lower PH clay..rapid dehydration.

 

Will send other info per PM.

 

Nerd

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docweathers    79

This is a crackle / crawl glaze. It's supposed to break up into potato chips to form a very interesting pattern. The issue is not to suppress the crackling but to get the potato chips to stick to the pot. This all works very well on horizontal surfaces but it's really hard to get it to stick on vertical surfaces.

As previously mentioned, I found ways to get it to stick, such as adding some Elmer's, but that suppresses the formation of the potato chip. You can see one variation of what it does in the picture ti the left.

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Tyler Miller    331

I sent this suggestion to Larry via email, but thought I'd take the plunge and post it for public benefit:

 

Swap the ball clay for a less plastic kaolin. The glaze will still crack and crawl (though not as severely), but the lower shrink rate when drying won't mean such strong forces, meaning more glaze will stick. Hopefully.

 

The chem is a little different, but at 5% the clay's job is just to work as a binder.

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Joseph F    866

Have you tried making the glaze like a gel? Not by decreasing or increasing water, but by adding so much flocculant it is a gel consistency? I used to glaze some stoneware that I bisqued really high with this method because glaze wouldn't absorb well into the high bisqued pots so I used the gel method to get glaze to stick until fired.

 

I also do this with a snow flake crackle glaze that I am experimenting on. The glaze will flake off the pot and fall into the shelves unless I make it gel like. This makes the drying time for the glaze really long, like a day plus before I can handle the pot, however it wont fall off the pot during the firing it seems.

 

I am guessing you have probably already tried this? This also might make application really tricky if your trying a certain thing, but just a thought to try. 

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docweathers    79

Joe

The gel sounds like a fairly simple solution that might work. I will give it a try.

It looks like I have a whole bunch of options to test.. Of course, that's the fun part.

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Joseph F    866

Joe

The gel sounds like a fairly simple solution that might work. I will give it a try.

It looks like I have a whole bunch of options to test.. Of course, that's the fun part.

 

I am excited to see what your doing. I have been gelling a bunch of glazes lately to get the same sorta results your probably trying to get. Just opened a kiln with some nice ones. Hopefully we get to see your results soon? Always like to see interesting surfaces.

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glazenerd    816

Okay Doc

First you do not want to flake off, now you want flakes that stay on. Flakes it is, think I already know, but will test it first. Good thing we are friends..lol

Nerd

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glazenerd    816

Like this Doc?post-73441-0-29867800-1502147343_thumb.jpg

 

Big flakes, that do not flake off?

If so, will have to mail you the clay to do it. Not sold in the pottery biz.

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Tyler Miller    331

I read up on lalone crawl tonight. I think I figured it out. It's not a dip/pour glaze, you brush it on in successive thin coats. No need to mess with the recipe, just slowly build up the glaze in 3-4 brushed coats. It has to be ball clay, it has to be uncalcined mag carb, and it must go on thin with drying time between coats to keep from flaking off. Instant drying kind of thing.

 

Back to the woods.

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