UV Smooth Prime
 

I'm doing my fibreglass work now and have read a bunch of different threads on how to prepare for priming. A lot of different options. With respect to the UV Smooth Prime, do I have to do a bunch of pinhole filling before applying it or is this primer meant to fill the pinholes with one or two applications and some sanding?

It is designed to fill pinholes. Stir it well, drip a little on the surface and use a credit card to squeegee in the first coat or two. After that, roll on a coat, and sand when dry. Be sure to follow the drying requirements in the instructions before top coating.

I used it on the RV-10 after a high end Lancair builder recommended it. I will never use it again. It added a lot of work for limited value. There are better ways to fill pin holes.

If you use it, never wet sand like you would do with a high build primer or a skim coat of micro. Smooth Prime absorbers the moisture - and it takes weeks for it to dry out before you put the real primer on it.

Carl

Fill the pinholes first
 

I have to agree with Carl,, I tried to get the UV primer to fill the pinholes I Couldn?t see before I primed, it failed miserably, from here on I?m going to use a squeegee with slow curing epoxy diluted with acetone to make it thin enough to go down in the pinholes before I get any primer anywhere near the cowls , be sure and sand off any mound release wax before hand with some 120 grit sandpaper , wish I had asked here before I forged ahead on my first build !!

There are a lot of different ways of filling pin holes, that work. Each does require specific technique to be successful.

The most important which is applicable regardless what method is used, is that the material be squeegeed on in multiple directions on the surface being treated. Up, down, left, and right, if possible.

I have used both the squeegeed on smooth prime, and straight epoxy resin (not thinned) with great success

Have you used this method with success Kyle?

Thank you Scott for the application tip. I think that I will try with straight epoxy as you suggest. When you say squeegee, are you referring to a rubber squeegee or plastic like a credit card?

Thanks for the tip on the release wax.

I have used drywall spackle to fill pinholes. Just rubbed it in with my fingers, let dry, sand, wipe (don't blow), and primer. Works great! 200 plus hours now and no issues with the technique.

Yep. There is an RV-6 around here somewhere as evidence.

The thing I like about UVSP is there is little wait between squeegee coats. It does its job well, and sands easily. The wait before applying an epoxy primer or finish coat is the downside.