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High Bridge Pottery

Member Since 19 Feb 2013
Offline Last Active Yesterday, 06:34 PM

#114825 Epic Fail Making Slabs

Posted by High Bridge Pottery on 18 October 2016 - 01:22 PM

There is a lot to be said for how you recycle the clay. I think most of the shortness is to do with not getting the water in between every clay particle. Excess water over bone dry clay (a good 3 inch of water above the clay line) and multiple mixing over a week or so then another few weeks to let the water evaporate so it was an acceptable consistency to dry out on a plaster batt. It takes time and space, not something everybody can do. I guess I am ageing in excess water instead of mixing and then ageing at the right consistency.


I also try and add all the throwing slop back in to keep as many of the tiny particles or anything else in the water.


I don't like rolling slabs and will get to the right thickness by cheesewiring with a harp or thickness guides and then rolling if I have to. Even if your surface is plaster and not making the clay stick it always sticks to my rolling pin. Finally I can't even roll something the same thickness and get a more even slab with a wire.

#114824 Old Chemicals

Posted by High Bridge Pottery on 18 October 2016 - 12:57 PM


rocks are millions of years old already, a few more won't matter


Does granite decompose and turn into china clay because it is too old to stay as granite, or is it because it was poorly made in the first place?



It is something to do with slightly acidic water disassociating the KNa and some Si from the feldspars and making/leaving kaolin.

#114793 Old Chemicals

Posted by High Bridge Pottery on 17 October 2016 - 07:30 AM


rocks are millions of years old already, a few more won't matter



But how can you be sure?  What if One million and one years is the limit?!!!...Hehe....



You can tell a rock is out of date if it has turned into clay ;) but then it is in date for clay  

#114655 Old Chemicals

Posted by High Bridge Pottery on 13 October 2016 - 11:30 AM

rocks are millions of years old already, a few more won't matter

#114219 Seeking More Technical Understanding Of Firing To A Cone

Posted by High Bridge Pottery on 03 October 2016 - 08:24 AM

Could set up a Wikia http://pottery.wikia...i/Pottery_Wikia

#113540 Flux Formula Limits For Porcelain

Posted by High Bridge Pottery on 21 September 2016 - 04:31 PM

I have tried to share parts of this documentary before and failed. Let's see.


At 10:30 there is a interesting animation firing porcelain on the inside, lots of liquid phase. I agree that you could be putting too much weight into gassy KNaO. Surely most of it is staying in the clay body or glaze? 


Good documentary.


  • Min likes this

#113147 Colour Response Of Base Glazes

Posted by High Bridge Pottery on 14 September 2016 - 04:03 PM

Without you posting the recipe I am just making a guess that there is not much frit in the recipe and not too much boron. It will still be adding something to the colour but I think the double soda is probably the biggest help and I have assumed there is little boron.


Bath Potters are expensive, is that £45 before postage? I like CTM http://www.ctmpotter...o.uk/prod04.htm and their website says £50~ for 5kg calcium borate frit, nearly half price ^_^ . I did buy most materials in 10-25kg lots but I have never calculated 10kg of dry glaze material to be more than £20


I would think a high alkaline frit is a good start for getting somewhere in the middle of the two glazes. 2-5%

#113139 Colour Response Of Base Glazes

Posted by High Bridge Pottery on 14 September 2016 - 02:57 PM

I think the colour response is more to do with double the feldspar so a much more alkaline glaze (KNaO). I have always found a little frit at cone9/10 is worth every penny. Glaze cost per pot is in the low pennies for any glaze I have made, maybe 2p-8p based on 300 pots a bucket of glaze.

#113044 Nerd Playing With His New Toy

Posted by High Bridge Pottery on 13 September 2016 - 05:32 PM

Last photo is the best. Hard to light very small shiny things and take pictures. 


I was looking for a different video but stumbled across this one. Small and melty.


#112586 ?turquoise Yellow Salt Glaze

Posted by High Bridge Pottery on 05 September 2016 - 08:00 AM

I think the =25 is some weird way that the % sign has converted/displayed/archived.


So you just have 1/8% cobalt and 2% copper.


This other recipe I found kinda backs that idea up except they are using 1/4 cobalt instead of 1/8. http://cindywennin.c...low-salt-glaze/

Turquoise Yellow Salt Glaze

Cone 10 Reduction
Nepheline Syenite 63.9
Dolomite 21.1
Zircopax 16
OM4 Ball Clay 4.3



4% Bentonite

0.2% Cobalt Carb
2.0% Copper Carb

#112366 Community Challenge #6 The Results

Posted by High Bridge Pottery on 01 September 2016 - 06:58 AM

This was the clay self-portrait challenge.
Original thread - http://community.cer...ty-challenge-6/


#112188 Understanding Glaze Chemistry Workshop | Nov. 12, 2016 | Manchester Nh

Posted by High Bridge Pottery on 29 August 2016 - 08:19 AM


If only it was in Manchester, England.


Deja-vu moment ........



Did I make the same bad joke last year ?  :D

#112084 Me No Understand!

Posted by High Bridge Pottery on 27 August 2016 - 08:46 AM

They don't scale the same, 50f may be 10c but 100f is 37.777c, 200f 93.333c.


I guess you can only look at them as ratios 1:4 and so on, so 25c/h up to 100c.

#111534 Struggling To Get A High Gloss Cone 10 Transparent Base. What I've Tried...

Posted by High Bridge Pottery on 17 August 2016 - 01:54 PM

You're welcome, it is from Newcastle College ceramic department. Not sure who came up with it. Do you have some pictures of the tests? 6% seems like quite a bit and will be changing the glaze chemistry as you can see. Could be if you are colouring the glaze with that much stain each one could need a slightly different recipe to have the right surface.


Have you tried using it to colour slip or paint on as underglaze and using a transparent over that? It could help the problem but maybe lose what you are looking for in colour.

#111460 Making A Glaze More Runny

Posted by High Bridge Pottery on 16 August 2016 - 10:43 AM

Just about to say that myself Fred :D Interesting book, look for second hand books as I bought one for 1/10th of the new price.




I have not seen high calcium make a glaze very fluid except in weird situations where something crystallizes out my glaze and then makes it very fluid in that area. Still dropping the alumina will get you closer and increasing the calcium may help it along.