How To Stop Glazes From Bleeding Into One Another?

[docweathers]

Does anyone have any magic tricks to keep adjacent glazes of different colors from bleeding into each other rather than having a sharp edge between them?

[Pres]

If you want a sharp edge, you could try a wax resist line where they overlap. Put the first glaze on, then brush a 1/2" or so of wax resist, to the edge of that glaze, then apply the second glaze. In some cases you might even like the wax resists the are colored-mostly black. Another way is to have an actual ridge in the form where one glaze comes to the ridge and puddles in the firing, and the other glaze is below the ridge. All possible, but I don't know if one of these will help you with your problem.

 

best,

pres

[docweathers]

thanks for your input

 

are you  saying to apply the second glaze actually over half inch of wax resist? how do you get it to stick and what does the under coat of wax resist do if you can get the second glaze to stick to it?

 

I'm not talking about glazes that are overlapping but ones that I have used wax resist or latex to get them to just touch each other, not overlap

[Min]

Not sure if I'm following you but if you don't want 2 glazes to bleed into each other then I would use stiff glazes and use the same base for both colours. Apply glaze #1, wax over it like Pres said, wipe off any of glaze #1 that is where glaze #2 will be, then apply glaze 2. If the base glaze is the same, and not a fluid one, you should get a crisp line. clear as mud?

[docweathers]

I was hoping not to have to mix special stiff glazes from the same base to get this to work.

 

I am doing the wax, wipe off procedure that you suggest. it's really not a matter of glazes running into each other from the force of gravity. Sometimes they actually diffuse uphill, against gravity. Though the glazes touch, sometimes I actually have an edge between the glazes. 

 

I was hoping there would be some material that I could make a fine line with between the glazes that would act as a barrier. Know of any?

[GiselleNo5]

Larry, have you tried slip trailing? I've used it as a barrier between glazes and it works pretty well.

 

http://community.ceramicartsdaily.org/uploads/gallery/album_947/med_gallery_67168_947_15780.jpg

[Chris Campbell]

I seem to remember that majolica products don't move much so can be used this way but not 100% sure.

Anyone use majolica colors or glazes?

[Babs]

I use Maj, but only use the white glaze so have never tried to overlap etc but the glaze stays still.. may be a way to go.

[Pres]

thanks for your input

 

are you  saying to apply the second glaze actually over half inch of wax resist? how do you get it to stick and what does the under coat of wax resist do if you can get the second glaze to stick to it?

 

I'm not talking about glazes that are overlapping but ones that I have used wax resist or latex to get them to just touch each other, not overlap

Not really doc, I am saying to use the wax line to help get a clean edge, Overlap just enough to cover any bare surface to the wax, rub off any excess on the wax. I do this with my fingers as a cloth for me hits too much of the surface.

 

best,

Pres

[docweathers]

The idea of using slip trailing as a border between glazes seems most likely to get me what I'm looking for.  

 

Thanks

[rayaldridge]

That's a problem I could not completely solve, because I don't like glazes that are too stiff to move.  I think you're right that a physical barrier is your best bet.  This can either be a ridge or a depression-- I usually score a deep line at the base of pots I intend to glaze with somewhat runny glazes, because often that is enough to stop the downward movement of the glaze, if the glaze is not too thick.  And now that I think of it, thin glazes will be easier to keep distinct.

[glazenerd]

Would be interested in an extreme close- up pic. Would also like to know in the future if the slip solved the problem.

Did this problem pop up after a change in clay inventory? Ongoing problem, just started?

Nerd

[graybeard]

I'm just spitballin here but what about using a simple under glaze?

 

gbeard

[GiselleNo5]

Graybeard, I use underglazes before bisque firing and you're right, generally they don't move a tad even if the other glaze is right on the line.

[Chilly]

+1 to the use of underglazes.  

 

I was taught to use underglazes when I wanted precision, and glazes when I wanted flowing, mixing or surprises.

[Benzine]

That's what I tell my students, as an overall rule Chilly.  

 

I only do low fire in class, so many of the glazes stay put on their own.  But even so, a glaze next to a glaze, or especially on top of another, do lose some of their clean edge, due to the fact they melt and flow.  

[GiselleNo5]

I had forgotten a couple techniques, hope it's not too late to share. 

 

With my cups, mugs, and bowls, I almost always do a different color inside than outside. I like a crisp line. So I glaze usually the outside first, clean up the edge, and let it fully dry. Usually overnight is best. Then I glaze the inside either with brushing or pouring it full and dumping it. If the second glaze goes on top of the first I LEAVE IT ALONE. I do not wipe it right away or it will have softened the glaze underneath and it will wipe down to bisque. I let the second glaze dry all the way, then tease it off with a damp soft rag. It comes right off the dry glaze underneath leaving it alone.

 

This works too: I still do tend to use underglaze for this but paint on the design and then leave it to fully dry overnight before glazing anything over it. I've had good results with that as well. 

 

Last one: I've painted black underglaze on top of other (fully dry) underglazes to get a fantastic crisp design with no running or streaking at all. 

[docweathers]

glazenerd asked for a picture of the problem. such is attached. 

 

The purple glaze is pikes purple white is waxy white. The white was applied first then latex was applied over it, carefully coming up to the ridge at the edge of the carving. The purple was sprayed on. Then the latex was peeled off. The peel edge of the latex aligned very well with the edge of the carving.

 

I only use one clay, G mix 6 with grog from George's in Portland, and it's all the same batch. This is a new problem since I have not previously tried putting these two glazes juxtaposed to each other.

[Babs]

Could the purple be a little thick?

I'd be tempted to latex where the white is to go, spray the purple, peel of the latex then slip trial the white in to the depressions, leave to dry then any white spills can be Gently "scratched off.

Or liquid waxing the white, if applied first, then there is no need to peel the latex off the white glaze which may be thinning it slightly in places,

it may be the purple is edging under the latex because of the powdery nature of the white glaze prior to firing.....

[Paul Lewing]

The solutions to your problem that have been proposed have all been process or physical fixes, but the root of your problem is chemical.  If you want glazes to bleed a long way into each other, they need to be very dissimilar.  Conversely, glazes that are similar will bleed into each other less.  And the key area of difference is Si:Al ratio.  If the two have ratios have difference from each other that is greater than 6 they will definitely bleed a lot.  For instance if one has a Si:/Al ratio of 5 and the other has a ratio of 12, expect a lot of bleeding.  This of course makes sense.  One is deficient in silica, the other is deficient in alumina, so the go looking for what they need in the other.

So... bottom line, if you want no bleeding at all, your best bet is color variations on the same glaze.  Doesn't matter what glaze it is.  The the only variable will be how much of a flux or refractory the colorant is in each different color variation.

[Guest JBaymore]

Welcome to the forums, Paul.  Glad that you decided to join.  Of course I was thinking of not approving your new account here.... but ....well.... you know.... couldn't get away with that........  .

 

Good stuff you just shared (no surprises).

 

Now we need to get Ron Roy to join the forums here too,....... and the three of us can recreate the "Beyond Alchemy" presentation team from NCECA.    What year / location was that?  I can't remember.

 

Maybe get some images up in your private "gallery" section when you get a chance.  It would be great to get some china painting stuff into the mix here.  Plus the work is amazing.  There are a number of opeople here working in tile too.

 

Looking forward to seeing you out in Portland next year.

 

best,

 

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

[Chris Campbell]

Welcome Paul!

So very glad you are on the forum. You have a wealth of information to share and we aim to get it!!

: - )

[Val]

You did not say if you are using eathenware or stoneware? For earthenware Stroke and Coat by Mayco does exactly what you want , but at higher temperatures it will run together. For stoneware I have to use underglazes with clear on top to achieve detail

[Tom]

I get hard edges in glazing but not in 1 glaze firing. In the first firing the high fire light color glaze covers the entire piece. Then after the high fire I use a low fire paint on style darker glaze over the high glaze and fire it to its recommended cone. This has given me the sharp lines. The low fire glazes seen to fuse into the high fire glaze well. It's kind of like using China paints

 

Worth a shot