another question on secondary coatings

Quoting RQ.

RQ> I have found that the benefits of a heavy coating on the 
RQ> secondary far outweigh the advantages of a light or non-
RQ> existent coating. Also, there are a lot of beginners out 
RQ> there. Beginners especially need the physical and electrical
RQ> ruggedness that a heavy coating provides. 

	Many of the coatings that people have mentioned in this group are 
kinda loss. Even polyurethane is rather lossy, though  in the thicknesses 
used I would hope that the coil Q would not be degraded much. 

My question 
is this: have any of you measured coil Q before and after coating?

Last year, I made a coil on a PVC form wrapped with waxed paper and then coated 
the coil with 2 coats of varnish. The form could then be removed from the 
"free" standing coil which was held together with just varnish. I found that 
the coil Q with PVC form was about 15% lower than without! But I never did the 
experiment as a function of coating thickness....

-Ed Harris