Recommended thinner will be whatever the can calls for in the clean up
instructions. If Helmspar is an oil based varnish I imagine it will be
Two notes on spraying an oil based varnish.
No matter what equipment you use to spray with you will get some over spray
and bounce back. An oil based varnish stays tacky for a comparatively long
time, don't spray around anything you don't want to have to be scraping
little beads of varnish off of.
Unlike shellac or lacquer varnish does not have a solvent. In other words
you will not be able to spray something through the gun to get rid of any
cured varnish. DO NOT let varnish sit in the gun and clean it immediately
after spraying if the gun has to sit for even a short period of time. Should
you fail to do so and end up with cured varnish in the gun you will be
chipping it out. This is not a good thing for the gun.
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