AngryMeerkat Posted April 21, 2014 Share Posted April 21, 2014 Thanks for that David, yes it helps but also creates some confusion (as all good problems do!). The roughness is consistent with thinner entrapment, the heat forcing the thinners to evaporate and cause tiny air holes, or the roughness you describe. The confusion comes from a solvent (white spirit for example) based acrylic (water based) paint. The 2 aren't compatible in the same mix, water and solvents cause many problems when used wet. Your solution of rubbing solvent thinners over the surface means the varnish is solvent based, and the solvent you added basically 'melted' the surface of the varnish and filled/smoothed the top coat. This solves a big part of my problem, as it's a technique I've not thought of using before, so thanks for that. Out of curiosity could you post the name of the varnish you're using? I would be interested in finding out more about their mix. Lastly don't be spending too much time in the German Bar over in Bangkok, I did while living over there and it cost me FAR too much money! So I moved to KL and found karaoke bars, didn't save any money there either! Mark Link to post Share on other sites More sharing options...
david.hill64 Posted April 21, 2014 Author Share Posted April 21, 2014 Thanks for that David, yes it helps but also creates some confusion (as all good problems do!). The roughness is consistent with thinner entrapment, the heat forcing the thinners to evaporate and cause tiny air holes, or the roughness you describe. The confusion comes from a solvent (white spirit for example) based acrylic (water based) paint. The 2 aren't compatible in the same mix, water and solvents cause many problems when used wet. Your solution of rubbing solvent thinners over the surface means the varnish is solvent based, and the solvent you added basically 'melted' the surface of the varnish and filled/smoothed the top coat. This solves a big part of my problem, as it's a technique I've not thought of using before, so thanks for that. Out of curiosity could you post the name of the varnish you're using? I would be interested in finding out more about their mix. Lastly don't be spending too much time in the German Bar over in Bangkok, I did while living over there and it cost me FAR too much money! So I moved to KL and found karaoke bars, didn't save any money there either! Mark The original varnish was the Humbrol satin coat acrylic aerosol: I thought that the Humbrol acrylics were water based, but am happy to be put right on that one! The Japanese acrylic is definitely solvent based but not with the same base as enamel paints: they don't mix at all. I was worried about the thinner acting as a paint stripper and there was light residue of black on the cotton after. I have just test sprayed the Japanese Mr Color semi gloss and flat varnish onto some test pieces to see how they look. Had a few pints of Greene King IPA in the 'Pickled Liver' last night while watching the footie: safer and less expensive than the other distractions (so I have been told). David Link to post Share on other sites More sharing options...
sandwich station Posted April 21, 2014 Share Posted April 21, 2014 I thought all acrylics were water based? Link to post Share on other sites More sharing options...
david.hill64 Posted April 23, 2014 Author Share Posted April 23, 2014 Resprayed last night with the Mr Color Semi Gloss varnish. Success I think! Will post better photos when the light is better Link to post Share on other sites More sharing options...
TheWeatheringMan Posted April 24, 2014 Share Posted April 24, 2014 Hi, Regarding the comment about all acrylics being water based. No by no means are all water based. There is a formulation known as Alkyld Acrylic that although not now used very much was once the norm for several British Rail colours from BR Spec.81 (Brushing Finishing Paint) The last colour I handled that was of this type was 'Engineers Olive Green' as used on PWay dept. rolling stock. The paint was made by T & R Williamson of Ripon. This type of paint used acrylic pigments but was a solvent born material thinnable with white spirit. Although uncommon in the hobby field similar but more finely pigmented paints would be easy to produce and I imagine the Japanese paint you refer to would be of this nature. The information from 'AngryMeercat' regarding trapped moisture in the varnish film is totally correct - I know from other posts that he works professionally with paint and always offers excellent advice. For myself, to keep things simple, for many years I've been involved with paint and solvent research and am easily described as a paint and colour chemist. Hope the above is of interest. Regards. Link to post Share on other sites More sharing options...
david.hill64 Posted April 26, 2014 Author Share Posted April 26, 2014 A better photo after the treatment: Link to post Share on other sites More sharing options...
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