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BlackbuttWA
31st December 2011, 10:49 AM
Wattyl Estapol Varnish.
I sprayed a burl platter with Wattyl Matt finish & left overnight. The next morning I was surprised to find all the little indents, holes & cracks were white.
This is what the Wattyl rep’ told me :-
All Varnish is originally made in Gloss. To turn Gloss finish into a Semi-gloss, a fine white powder is added. To make it a Matt finish more white powder is added.
Apparently when spraying a flat surface it is not noticeable, it is only on irregular surfaces it is really noticed.
I just happened to be unlucky & get a bad batch. Although he gave me some thinners the burl was completely ruined as at that time I did not own a Longworth chuck or anything else that would allow me to re-turn the platter.
Hope this helps someone.

Cheers
Col
rustynail
31st December 2011, 12:56 PM
Do you have any idea what the moisture content was in the burl and was it humid when the finish was applied?
BlackbuttWA
1st January 2012, 09:16 AM
The burl was completely dry, it ha been in my shed for about 5 years & was cut down years before that. There was very little humidity .

The rep' said there had been a fault with in the mixing process & way too much powder had been added.

Col
Big Shed
1st January 2012, 09:24 AM
Doubt whether this was caused by a bad batch of Matt Varnish, if it was then it would show up in the flat areas of the burl as well.

What is probably the cause of your white appearance in the low areas is that too much varnish was sprayed on wet-on-wet which then collected in the low areas giving excessive film thickness there and showing up as white caused by the silica based matting agent in the varnish.

This could have been overcome by multiple thinner coats being applied.
bsrlee
3rd January 2012, 08:14 PM
White or frosted appearing 'clear' finish is also a problem for painters of war games figures. One of the recent 'cures' discovered is to apply Olive oil to the afflicted paint job

Dust, Tears & Dice: Matt Varnish Frosting... A solution ? (http://dusttears.blogspot.com/2011/12/matt-varnish-frosting-solution.html)

beats soaking it in paint stripper and starting again.