Hello,
Please can you help me with following notion.
I just ordered Paraloid B72 in ethyl acetate from Kremer to isolate lean egg tempera (ET) prior to oil glazes and realise I don’t know it’s ph value. SDS states N/A. Pure ethyl acetate SDS also, while acetone states ph: 5 – 6 (0 mg/cm3; 20°C).
Why I ask this? Is solvent ph important since my ET has synthetic ultramarine pigment which we know to be not compatible with acids?
One conservator answered me that ethyl acetate is very litle acidic and would evaporate fast so there shouldn’t be problem with that plas also that binder would protect it.
I would like to get second opinion.
Kind regards,
Damir P.
Not my area, but wouldn’t that place it somewhere in the same range as linseed oil? So probably it would be fine.
Marc.
While it is true that oil can have acid numbers and there are other materials like resins that contain acid groups, and yes ethyl acetate has an acetate group which is slightly acidic BUT you really do not need to think about pH in a non-aqueous environment. PH has to do with proportions of H+ and OH- ions in an aqueous environment. PH has no meaning in a non-aqueous system. Therefore, do not worry about the ultramarine. No whether ethyl acetate is the best solvent for B-72 is another question. My guess is that it is perfectly fine but I always use ethanol, xylene, acetone, or a combination of those.