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Dorsal
02-12-2009, 01:33 PM
Looking for comments from those who have experience painting polytone over non-fabric surfaces.

Dave S
02-12-2009, 04:09 PM
Dorsal,

The Poly Fiber manual says that a person should prime a metal surface or fiberglass surface with EP-420 Primer - let dry - scuff sand the primer with 400 grit sandpaper - then apply polytone. This is the tried and true procedure approved by the manufacturer. It works.

Now - this Iowegian also experimented with using plain gray brand X auto lacquer primer over aluminum - watersanding the dried primer to a satisfactory finish - then shooting the polytone over that. Did that on a piper tripacer cowl and other aluminum for the same plane 5 years ago - held up just fine - looks as good today as the day it was applied. (This little experiment was based on the theory that polytone is essentially like lacquer in the first place - it is a pure solvent dry system - no catalysts and no polymerization on hardening) ALSO BE ADVISED _ THIS EXPERIMENT IS NOT IN THE POLYFIBER BOOK)

On thing is immutable....You ABSOLUTELY need to do a good job of sanding the surface with fine paper to provide enough tooth if you want the polytone to stay where you put it for a long time. You can ask me why - just don't ask my neighbors at the local 'port how they know this.

Polytone is just about the easiest paint system to work with on an airplane. The book is great too.:)

Sincerely,

Dave S
K7 Trigear
912ULS Warp
St Paul, MN

hansedj
02-12-2009, 05:21 PM
Went to polyfiber web site under tech questions preparation of surfaces, and prepared my parts that way before spraying the epoxy primer. Then sprayed per the book.

Dorsal
02-12-2009, 06:19 PM
the book suggest two different methods, prime dry scuff and paint vs prime and paint while tacky. Just curiouse if others found one or the other or, as it sounds from above, both to work well.

Skybolt
02-13-2009, 09:13 AM
You will allways achieve a nicer finish if you allow the primer to dry and sand, before spraying color. That is of course if you use the correct grit size sandpaper.
You will also keep trash to a minimum because you have removed the trash that could have collected in the primer coat/s.

Make sure that you have the correct primer for the substrates, you don't want any paint peeling after some time.

hansedj
02-13-2009, 01:03 PM
I sprayed the primer let cure for 4 days then sprayed primer again and then sprayed the top coat into the tacky primer. I think the book says that.

Dorsal
02-13-2009, 01:59 PM
DJ,
Thanks for the info, what was the approximate time till tacky? and can I assume you are happy with the results?

hansedj
02-16-2009, 07:43 PM
I worked on one part at a time, say I sprayed the cowl, I had the top coat ready in a quart jar. I sprayed the cowl with the primer, went and ran solvent through my gun filled with top coat and sprayed. 5-7 min tops. My paint booth was 65 deg. Very happy with results, polytone is great, if I get a scratch I have a little touch up gun, spray it and it blends right in.