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-   -   Filler Primer (https://vansairforce.net/community/showthread.php?t=128452)

jswareiv 08-10-2015 06:31 AM

Filler Primer
 
In the new video from Van's showing how to fiberglass the front of the canopy (fairing)(great by the way), they mention using an filler primer and rolling it on for the finishing step to fill any remaining small pinholes. They don't mention a brand of filler. Looking around here, is K36 the recommendation? If rolling it on, I'm guessing sand the first coat with 400, then reapply? Recommendations on nap of roller? After all the hours spent fiberglassing and sanding, I would hate to mess it up. Every part of this process has been a learning experience. I appreciate the help, thanks.

Mike H 08-10-2015 07:52 AM

I have used this filler many times and it is very easy to work with and sand.
http://www.eastwood.com/evercoat-lit...er-gallon.html

I have also used Evercote Dura Build on a couple of cowlings and other comosite parts with good results.
http://www.autobodytoolmart.com/ever...G5A&kpid=13450

DanH 08-10-2015 08:44 AM

Quote:

Originally Posted by jswareiv (Post 1004664)
In the new video from Van's showing how to fiberglass the front of the canopy (fairing)(great by the way), they mention using an filler primer and rolling it on for the finishing step to fill any remaining small pinholes. They don't mention a brand of filler. Looking around here, is K36 the recommendation?

All primer-fillers (aka high-build primer, primer-surfacer, and often primer-sealer) are a base liquid suspending a solid bulk media. Most of the good primer-surfacers these days are acrylic urethane base. The common bulk media is talc or similar.

Years ago, the base was polyester. In the immortal words of Monty Python, "Run away, run away!"

Any solid (or liquid that turns solid) that you can work down into the pinhole will satisfy the basic requirement. We have good builders here who swear by drywall compound, and I don't doubt river mud would work well too. The question is how will the chosen filler (1) react long term with the substrate and the overcoats, and (2) hold up to environmental conditions, mostly a matter of heat and moisture.

Note that in the above, the material is not used as a surface coating. It is not a layer in the stack of primers and paints. Its all sanded off, leaving just the material down in the holes.

I quit using acrylic urethane surfacers for pinhole work some time ago. It's good stuff, but they all cure in the usual manner; the solvent evaporates out, then cross-linking hardens the material. Although it's not difficult to work the primer down into the pinholes (squeegee, roller, old credit card, whatever), I find that as the solvent evaporates, the pinholes tend to re-appear as little depressions in the surface, or re-open. So you let it cure, reapply, sand again, reapply, sand again, etc. I prefer an epoxy wipe, as there is no shrinkage during cure, no long term chemical or environmental issues, and it's a one-shot application.

I do use a lot of high-build primer for its intended purpose, as a final build coat prior to topcoat. Spray a contrasting epoxy primer, then spray a few mils of high build, then block sand to eliminate the last little fine ripples in the surface.

broken1234 08-10-2015 09:17 AM

Also consider WLS primer, which can be bought directly, or through Lancair. It is an epoxy based filler primer/surfacer. It all ships from the west coast, so factor shipping costs into the purchase price...

jswareiv 08-10-2015 09:25 AM

Primer Filler
 
Quote:

Originally Posted by DanH (Post 1004707)
I prefer an epoxy wipe, as there is no shrinkage during cure, no long term chemical or environmental issues, and it's a one-shot application.

I do use a lot of high-build primer for its intended purpose, as a final build coat prior to topcoat. Spray a contrasting epoxy primer, then spray a few mils of high build, then block sand to eliminate the last little fine ripples in the surface.

Dan,

Speak slowly, remember, I'm learning. Here is the video and questions. My canopy looks like the first one and Scott uses some kind of primer filler than he rolls on. Rolling on would be preferable to me, since I really don't want to spray around my canopy, even though I know it is well covered. I want to end up with the same look as what Scott has, ready for paint?




comfortcat 08-10-2015 09:30 AM

Videos?
 
How do I get access to these videos?

Quote:

Originally Posted by jswareiv (Post 1004664)
In the new video from Van's showing how to fiberglass the front of the canopy (fairing)(great by the way), they mention using an filler primer...


jswareiv 08-10-2015 09:42 AM

Videos
 
Quote:

Originally Posted by comfortcat (Post 1004740)
How do I get access to these videos?

They are under support for the 14,
http://www.vansaircraft.com/public/service-rv14.htm

Chattin35 03-18-2017 07:35 AM

Anyone use Smooth Prime on the canopy fairing? Section 5 of the manual mentions it for the cowling.

Robert Anglin 03-18-2017 07:58 AM

+ 1, for Dan H.
 
Dan has it right on the button here. Just one comment, we use the West systems epoxy thinned out and spread to fill. you can use their system to do many jobs on you aircraft and other things. In the long run it is a good one to get to know and use all of it's different additives and mixes. Hope this helps, R.E.A. III #80888

Larry DeCamp 03-18-2017 09:34 AM

Thinner for West Epoxy ?
 
RobertA,
What do you use to thin West Epoxy with ? Doesn't an evaporating solvent pose the same pinhole outgas recurrence as solvent borne high fill primer Re : Dan Hortons comments. Not flaming, looking to learn cause I need a better way on my current project..Larry


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