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Crawl Glazes.

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Crawl glazes or beading glazes or Lichens or Reticulating glazes, whichever you prefer to call them, anything with a high Mag Carb content is what I'm referring to.


I like the effect of these (in the right circumstances) but am never sure if they are going to work or not.


What sort of consistency should I be aiming for with the mixed glaze and what is the best application method and thickness?   Dipping is rarely possible in the circumstances I like to use them.


Do they work better over a gloss glaze (they appear to to me) and is there a way to make them work better over a matt glaze or even just underglaze on bisque?

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Lana Wilson used underglaze slips as the base coat for her "lichen" glazes. 

I have seen other use Black clack as the only base.Ken Turner uses raku bare clay as the base.

There are many approaches.




I feel like this is the best way to go about it. Underglaze is more of a colored clay in reality isn't it? 


Ajjay, the appearance of glossy is probably more of the crawling of the lichen leaving behind some of the flux on the pot more than it is the crawling being glazed on a clear glaze. Perhaps?

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Joseph, thanks, I'd been following that topic with interest, although I've not had many problems with the glaze flaking from vertical surfaces. I do remember it happening once, but that's all.


I've used  crawls sparingly but am never sure how it's going to turn out and am unsure of the best method of application.


The formula I started with was taken from this website (istr:)  Soda spar, 30: Mag. Carb 30: FF3134, 10: Talc, 10: EPK, 20. When this has been successful the cracks between the eventual blobs of glaze have opened up as it dried. This hasn't always happened.


I'm trying a different formula now:- Nepheline Syenite, 75: Mag, Carb, 20: Ball Clay, 3:  Zinc Oxide, 2:. On application with a brush (my usual method) this has gone on just like a normal dipping glaze would with a brush (i.e. not looking as though it's the best application method). It's stayed there but hasn't cracked up at all.


I've been told that crawl glazes are likely to work best over a bisque fired underglaze, (or even a bisque fired ^6 glaze) and will give that a go.


The Magnesium Carbonate requires much more water than I would usually use for slaking down dry ingredients before sieving but I've tended to leave it like that as it gives a good thick coat with a brush.


My worst result ever was on a plate rim which was over a black satin matt glaze, the effect ended up not unpleasant, but in no way resembled a crawl glaze, (pic below).


I'm really wanting to know the best method of application and what the consistency of the glaze should be. 


I mix most of my glazes on the thin side which allows me to use both an airbrush and a larger spray gun. I rarely dip pots to glaze them  as with my limited output I can't justify making glaze in large enough quantities, (storage space also enters the equation as well)  but I do know  the correct consistency for a dipping glaze.








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Ajjay, the appearance of glossy is probably more of the crawling of the lichen leaving behind some of the flux on the pot more than it is the crawling being glazed on a clear glaze. Perhaps?



I've definitely used it successfully over a gloss glaze in the past. I think I still have a piece like that, I'll try and look it out and take a pic.


From the other topic " and trying to not mix the glaze too far in advance seems to help too.", I'd wondered about that myself.


Looking at that logically (well, economically anyway)  you won't be making a large batch of this glaze, so it must be brushed or sprayed rather than dipped. 


I've got a test tile (brushed on) in a friends glaze firing today and also a test (with some underglaze and some ^6 glaze on a pot) in my own bisque fire today to be glazed in a few days time.

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What you should be looking for is " crazing" type lines in your dried glaze. In my most recent testing, I have found that if the dried glaze actually " crackles", then it is much more prone to flaking off. I am using a slight variation of Doc's posted recipe, which is also similar to yours. In the next couple of weeks, I will post some variations, procedures, and other information. You are correct, I have found that mixing to a heavy cream consistency produces better results. I must also temper that by saying, still early in my tests.



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