ETLB Squawk Forums — Archive

What type and brand of varnish did you guys use and any problems with flaking after some age? I have parts of my plane that are several years old that was varnished as it was completed and flaky now.

Poly Fiber epoxy varnish.
No flaking.

Thank you, J

What I use for coatings like this is WEST System(tm) epoxy with the Special Coating Hardener.  It gives a great finish, has UV filters and since it has no volatile materials it stabilizes the wood completely as there are no micro passages from evaporating solvents.  If used on exterior parts I put three coats of Epifanes varnish over it for additional protection.  It has an additional advantage in that it makes softwood parts less susceptible to denting in handling, etc.

Tom

Tom, how would you handle the area that are old, there is mild flaking in a couple of spots which I will have to sand out I guess but if no flaking would you just over coat on it?

In the case of old coatings I'd try awfully hard to figure out what the original varnish was chemically.  If it is spar varnish which had volatile solvents in it original you don't want to try to coat over it with anything else.  If the varnish is deteriorated some combination of very fine sand paper and possibly very careful use of a cabinet scraper where it is flaking would be the best way to get a reasonable surface.  Try not to sand all the way through the coating any more than you can help, but remember even if the surface seems in good condition to sand thoroughly as you don't want to build up the thickness of the varnish any more than you can help.  Adding thickness to the varnish adds more weight than you'd ever believe possible.  On previously varnished surfaces which used conventional varnish with volatile materials in it I would use the highest quality Epifanes conventional varnish.  If the varnish is flaking in areas inside the aircraft where the sun doesn't get at it chances are somebody "saved money" by using "inexpensive" varnish.  This is one of those areas where "saving money" on the material itself is a bad idea.

Unless you are recovering your aircraft you are just going to have to do the very best you can.  If you were going to recover the aircraft I would say the safest best would be to go to carefully removing all the varnish, using a remover which will not damage epoxy and start from scratch with the WEST System epoxy and Special Coating Hardener.  Done properly you should not have to worry about redoing it ever again.

Tom

Sounds good, thanks so much Tom. James