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Old 30th Jul 2020, 3:16 pm   #4
PsychMan
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Join Date: Jun 2013
Location: Fleet, Hampshire, UK
Posts: 1,764
Default Re: What causes this in polyurathane varnish?

The bits that reflect the light, the wrinkly bits are the issue. They have texture which can be felt also. Its always near the edges too, and never in the middle of a surface.

Its exactly the same brand and type, same barcode etc and both bought in a short space of time from the same source.

The solvent theory does sound plausible, though how to prevent it is a tough one. I do give it a stir every time I use it. The new batch being thinner I assumed was due it being new, I.E the old one got thicker at the end.

One more point that could be relevant, I have been leaving the brushes in white spirit between use, and wiping dry with a rag before using it. Perhaps Im adding more spirit through the residue...
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