Dear MITRA community,
i want to ask does the soybean based bio solvent like the MH miracle medium will affect the durability of oil film?
i know it evaporate very slow if any, so the soy ester will for sure trapped inside oil film, and it doesnt contribute to drying nor form a film, not sure if this will affect the durability?
even for water mixable oil paint that the suffactant added, people still concern about long term stability in oil film.
and seems Michael saying traditional mineral spirit if used cuts the oil chain that affect its durability, which become bad to use, is that true?
so can any expert help to provde some thoughts?
Hello there,
Very volatile solvents like white spirit will evaporate. They won’t cut any oil chain that doesn’t exist yet. That makes little to no sense.
Solvents have the ability to keep compounds in solution, which doesn’t mean breaking them down to lower form than their molecular form (fatty acids, mono, di, tri glycerides and glycols). There’s nothing to break.
For oil paint in the process of drying, yes white spirit will impair it, if you were for some reason I cannot fathom to soak your paint currently drying in white spirit. Yes the solvent will resolubilise the oil it still can.
More dry oils become more and more resilient to solvents as the polymerisation takes place. Doesn’t mean white spirit will break it (if you are again to wash your paint with it because reasons). It will only solubilise the smaller oligomers that still can be solubilised.
Heavier solvents like ester can smell milder, have strong solvent properties and be less volatiles.
The risks, like using too much turpentine mixed with oil and varnishes in painting mediums, is to keep some of it trapped for ever as a plasticiser. This would reduce the drying properties locally and keep the film sticky, if to ever dry at all.
Heavier solvents are nicer to use, but dangerous for the film formation if they linger.
Like many things it depends on too many factors to say if one’s work is at risk. Amount, temperature, drying time, thickness and so on.
Personally I’ll keep the more volatile solvents. If you use these mediums with nicer solvents, I’d advise to be super sure they evaporate fully. Which is hard to tell.
Long term stability of the film wouldn’t be affected if all the solvent goes away. If some remains, the film will dry less, remain more flexible/sticky and solvent sensitive.
If there are a lot of surfactants in there (there are?), that also causes higher sensitivity to water to wash the dry paint, that’s not the best, but they can be washed off before a good varnish layer.
Good luck,
Lussh
Hi Lussh,
i believe the main benefit MH claims for his soybean based bio-solvent is it doesnt make the oil paint weaker compared with mineral spirit as well as it doesnt remove the oil from natural hair brush vs mineral spirit.
it seems indicate it doesnt have a strong solvency as it doesnt destroy the chemical chain of oil and not “degrease” natual hair completely?
it does sounds like something nice to use, plus it is none toxic compared to traditional solvent?
but on the order hand, does this leaves any residue in the oil film? there is no such info provided from MH. leaves many worry to artist who desires durability of oil paint, so is there any material expert may help to input?
