I've painted regular white mugs and want to varnish them too. But my varnish has the following specs:

Gloss varnish based on alkyd resin.

Flash point: Above 40 degrees celsius.

Is it safe to varnish on some sections of the painting on the outside of a mug? Or will it catch fire if microwaved to boil water or something?

I have no background in chemistry... took me a while searching around before I finally decided to just ask.


1 Answer 1


The flash point is for the solvent, i.e. for undried paint. Dried paint will have a considerably higher flash point, well over 100 degrees Celsius.

You should also consider toxicity. I don't think alkyd based varnish is approved for use in items you put in you mouth (like mugs).

  • $\begingroup$ Thanks! I'm only dabbing a little varnish on the outside of the mug, where a few designs have been painted. So that part won't be going inside the mouth. $\endgroup$
    – user961627
    Dec 15, 2016 at 21:25
  • $\begingroup$ Keep the varnish away from the rim and the mug away from the FDA and you should be fine. $\endgroup$ Dec 16, 2016 at 7:57

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