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InquisitivePotter

Wood Ash Glazes - Uk

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Hello everyone

 

I'm a complete beginner when it comes to wood ash glazes.  I have a couple of recipes, to which I can add oxides, but just wanted some help with some initial questions please.

 

I have been collecting wood ash from friends' wood burners.  I am guessing I need to sieve it first, and then there is the first question: to wash or not to wash?  What is the general consensus, and if the answer is to wash, how?  Dump it in a bucket and then drain it and leave it to dry?

 

I will be firing in an electric kiln at cone 9-10 according to the recipes I have (I believe that's 1280 in the UK).  If for any reason it only makes it to 1260 (which is cone 8) will the glazes not mature?  I ask because I'm firing in a friend's kiln which is struggling at really high temperatures, but unfortunately is the only one I have access to at the moment! 

 

I know sometimes in an electric kiln, depending on where you put it, you can set it to a lower temperature but there are hot spots in the kiln that hit higher temperatures you see.

 

My background is I have come to pottery later in life, having graduated from a degree in 2013.  Learned LOADS but as we all know, there is always so much more to find out about, and I do love a bit of glaze!

 

Thanks for your help in advance :)

 

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I wash my ash. This prevents it from running all over.Some people do not wash their ash. [That sounds obscene.

To wash;

Get a 5 gallon pail full of ash.

Fill with water from a garden hose. You should be wearing a dust mask.Also, you should wear rubber gloves as you are working with lye.

Skim off all floating unburnt charcoal.

Stir with a stick.

Using a window screen and another bucket, pour the liquid ash through the screen into the second bucket.

You can do this a couple of times. There are soluble fluxes that you are losing each time you wash.

The water is toxic. Don't put it on your lawn. You should be doing this outside, not on a windy day.

Decant all the water.Pour your left over ash onto a piece of canvas or other material and let dry. Then store it in a lidded pail. It is now a glaze material.

TJR.

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Hi from John Britt's midfire book,if you do a cone 10 , you would have to get it to come 10. He has cone 6 wood ash recipesin his book.i would get a cone 6 recipe or two , go with that if your friend' s kiln is having issues. The kiln will last longer, and since there are two of you using it.the glazes in his book are quite pretty.

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Britt's High Fire Glazes book would be a better choice for firing to Cone 10. It is excellent. Also when applying ash be sure to be aware that it needs to look thicker on the surface than non-ash glazes. 

Marcia

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Washing the ash makes it safer to handle, but less effective (but still very useful) in the glaze. Back when I used a lot of ash glazes, I always washed my ash because otherwise it would make my skin itch when I sprayed glazes. I washed it 4 times- add water to the ash, stir it up, let it sit overnight, decant all the water, add clean water, repeat.

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+1 on most of these comments. Britt's book is great for giving you a quick look at various optional glaze recipes. And yes put the ash glaze on thicker than other glazes because ash material is just bulkier and fluffier than your standard materials.

 

I never wash my ash (although I do dry-screen out the big chunks) I want all the character its mysterious blend of stuff can deliver. If you clean ash long enough, in the end you are just left with (in my case) a dirty source of CaO. No joy in that, as I can find plenty of easier ways to get dirty calcium.

 

Ash glaze CAN be very runny (particularly if you don't wash it) and until you have some level of control over it best to put waster plates under your ash glazed pots so you will be invited back to your friend's kiln for the next firing! I have found that there is a thin line between putting on too little ash glaze and having the glazed surface look stingy and bare, and putting on too much and having it run off the pot.

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Thank you all so very much lovely people!  I do have John Britt's Cone 6 book but not the high fire one.  I love his books (and him :) ) but I sometimes find it difficult to convert the ingredients to what we can get in the UK unfortunately.  I was definitely born in the wrong country for pottery!

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What do you have problems with? Most frits seem to not exist in the UK but other than that I have managed. I do just swap feldspars around with no care for the chemistry of each. Probably not the best idea but... the american names are too confusing being named after brands and such.

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What do you have problems with? Most frits seem to not exist in the UK but other than that I have managed. I do just swap feldspars around with no care for the chemistry of each. Probably not the best idea but... the american names are too confusing being named after brands and such.

Basically all the different feldspars and the frits! 

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Inquisitive, do you use glaze calculation software?  That would be your best approach to making those conversions. since the analysis of most materials can be found.

 

And remember, you were born in the country of Bernard Leach and Michael Cardew. 

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Inquisitive, do you use glaze calculation software?  That would be your best approach to making those conversions. since the analysis of most materials can be found.

 

And remember, you were born in the country of Bernard Leach and Michael Cardew. 

You can get glaze calculation software :o  How have I done an entire degree and not known this!

 

I know, we DO have a fantastic ceramics heritage and from that perspective I'm incredibly lucky.  I guess I mean we don't have as much space in the UK to do wonderful things like wood firings etc.  Plus we have our well known health and safety over here, which restricts an awful lot of what can be done.  

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Thank you all so very much lovely people!  I do have John Britt's Cone 6 book but not the high fire one.  I love his books (and him :) ) but I sometimes find it difficult to convert the ingredients to what we can get in the UK unfortunately.  I was definitely born in the wrong country for pottery!

You were born in the right country for pottery. Have you heard of English China clay- a cadillac porcelain sought after all over the world.Cornwall stone- a feldspar from Cornwall. Go to the Craftsman Potter's shop in London for good wood-fired pots. Look up Svend Bayer, Phil Rogers,John Leach. The pottery traditions came from the u.k. to the states, not the other way around.

There is an unbroken tradition of making good functional pots. Clive Bowen -wood fired earthenware.

Get off your butt and do some research.

TJR.

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Thank you all so very much lovely people!  I do have John Britt's Cone 6 book but not the high fire one.  I love his books (and him :) ) but I sometimes find it difficult to convert the ingredients to what we can get in the UK unfortunately.  I was definitely born in the wrong country for pottery!

You were born in the right country for pottery. Have you heard of English China clay- a cadillac porcelain sought after all over the world.Cornwall stone- a feldspar from Cornwall. Go to the Craftsman Potter's shop in London for good wood-fired pots. Look up Svend Bayer, Phil Rogers,John Leach. The pottery traditions came from the u.k. to the states, not the other way around.

There is an unbroken tradition of making good functional pots. Clive Bowen -wood fired earthenware.

Get off your butt and do some research.

TJR.

 

Thank you for your comments.  If you read further down, I qualified that I understand English pottery heritage.  I have completed a ceramic design degree.  However, if you read, you will also see that I have qualified my earlier, perhaps over enthusiastic statement.  I regularly visit the Contemporary Ceramic Centre in my home town in London, which I assume is where you are referring to :)

 

I wasn't trying to avoid doing research.  I generally find that people in the ceramics world are kind and sharing.  Ash glazes are something I know nothing about so I have only asked for some help on the start of my voyage of discovery.  I've done lots of reading, but that only takes you so far.  Also, I am on limited resources.  :)  Sorry, I hope this doesn't sound confrontational, because its not meant to be :) 

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talk to john leach in Muchelney, he is a sweetheart and very helpful.  sometimes he simply sprinkles fine dry ash on the top half of a pot and lets the kiln do the work.  don't know what that would do to the elements of the kiln, though. <_<

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Have you seen Phil Rogers' book Ash Glazes?  Great book, and he's one of the foremost living practitioners of the art of ash glazing.

 

I myself am a proponent of fake ash glazing.  If you use the right iron-contaminated clays, you can't tell the difference between real and fake ash.  The difficulties associated with real ash glazing in the studio more or less disappear when using fake ash glazes.

 

There may be a subtle spiritual difference between real and fake ash, at least to the maker.

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