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High Bridge Pottery

Member Since 19 Feb 2013
Offline Last Active Yesterday, 03:50 PM

#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.


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#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.

#111024 Qotw: Clay Poem Anybody?

Posted by High Bridge Pottery on 05 August 2016 - 04:56 PM

The slip.


The slip slop

did drip drop

and tipple top

until you stop

the pouring.

#110958 Qotw: Clay Poem Anybody?

Posted by High Bridge Pottery on 04 August 2016 - 01:56 PM


Taking the rockery.

Melting so hot you see.

Or not.

As fiery light so bright.

You can't see your pottery.

#110659 Qotw: Are Our Expectations Too High?

Posted by High Bridge Pottery on 27 July 2016 - 03:46 PM

I like peoples big aspirations and dreams but if you can't deal with failure then you quickly find pottery is not for you. No problem with people being naive and expecting to make great things before they have learnt anything.


I disagree about the internet or young people being the problem these days and the search for instant gratification has always been a human instinct. It has been played on by consumerism and advertising for much longer than the internet.  

#110556 Replace Frit 3134 With Gerstly Borate

Posted by High Bridge Pottery on 26 July 2016 - 03:02 AM

GB seems to change half the sodium flux for magnesium and comes with less silica.


You could mix in a bit of feldspar but then your alumina will be shooting up and alter the recipe. The best match may be to use GB with a little extra silica and ignore the changing of sodium for magnesium. Depending what else is in the recipe you could get a little closer swap.


Something like 1 frit 3134 = 0.77gb + 0.23 silica



#110294 Your Refractory Is Toast

Posted by High Bridge Pottery on 19 July 2016 - 07:47 AM

This video popped up in my subscription box and I thought it would be worth sharing on here. Haven't been able to find much about it's operating temperature or how long something like this would last but it sure is interesting making some refractory carbon out of bread. Seems like a bit of a strange one as in my head the carbon should burn away but maybe the reduction firing first changes something about the carbon.


Very crude ideas in the video but nothing like trying it out for yourself. 


Bread kilns here I come :D