Try out the suggestion from the “Nice Manners For A Thief” blog’s “How to save your dipped models from the dreaded Dullcote Frost“. Frosting (or that whitish build-up on model s0 is usually caused by a combination of poorly mixed and/or old varnish and temperature – varnish is quite fussy about the latter and if it’s too cold to too hot when you spray or brush on the varnish in will ‘frost up’… HSHP’s article specifically deals with the issue occurring when using the dipping technique, but the general rule applies for all varnish jobs gone bad… Well with keeping this little tip in the memory banks.