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how much glycerin or propylene glycol?

updated sat 7 jan 06

 

Bruce Lucas on sat 31 dec 05


I'm experimenting with setting up glazes for brushing, and have read
that adding "a little" glycerin or propylene glycol. How much is "a
little"? I've tried adding about 10% by volume and it seems to improve
brushability, but I'm not sure if this qualifies as "a little" and
whether too much might be harmful in some way.

My current best effort is the following:

100 g dry glaze
70 ml water
10 ml propylene glycol
1 g veegum cer

I've tried this with some success with a couple of different dry glazes
- a commercial dry glaze from Spectrum and Tony Hansen's 20x5 glaze.

Would be grateful for comments and suggestions!

Thanks,
Bruce Lucas

Steve Mills on fri 6 jan 06


Dear Bruce,

The most usual material for converting glazes to *Brush-ons* is CMC
(Carboxy methyl cellulose) plus a disinfectant (CMC is an organic
polymer, and so can degrade, disinfectant stops that).

If you go to:
http://www.bathpotters.co.uk/glazemake.html
you will find some basic information on making Brush-on Glazes.

Steve
Bath
UK


In message , Bruce Lucas writes
>I'm experimenting with setting up glazes for brushing, and have read
>that adding "a little" glycerin or propylene glycol. How much is "a
>little"? I've tried adding about 10% by volume and it seems to improve
>brushability, but I'm not sure if this qualifies as "a little" and
>whether too much might be harmful in some way.
>
>My current best effort is the following:
>
>100 g dry glaze
>70 ml water
>10 ml propylene glycol
>1 g veegum cer
>
>I've tried this with some success with a couple of different dry glazes
>- a commercial dry glaze from Spectrum and Tony Hansen's 20x5 glaze.
>
>Would be grateful for comments and suggestions!
>
>Thanks,
>Bruce Lucas

--
Steve Mills
Bath
UK