On Wed, 19 Nov 2003 23:13:39 -0800, "Evan Gatehouse"
wrote:


"Kenneth" wrote in message
.. .

Howdy,

I have a musical instrument case that I made of fiberglass. it was my
first such project, and the results were good.

The surface has some minor imperfections, and I want to paint the
thing with PBU. Some of the problems are small pits, also, in places,
the weave of the glass is slightly visible. I have seen that the
imperfections are emphasized by the paint and so this question:

What is the best way to "fill" these minor imperfections so that I
have a smooth substrate to take the paint?

Thanks for any help,
--
Kenneth

Are you going to beat up the case a bit or treat it carefully? If #1, then
I'd suggest epoxy mixed with microballoons as a fairing compound. Use a
plastic squeegee (available from marine stores, autobody shops) to apply the
stuff.

If you're going to be a bit more careful, 3M makes a nice line of "Marine
Fairing Compound" - it's like an expensive type of Bondo, but it is
compatible with LPU paints. It hardens very quickly so you can do more
fairing in a shorter period of time.

In either case, the procedure is fill pits, scratches, the weave of the
glass, sand, remove dust, repeat. Repeat until you're satisfied with the
finish. A common mistake beginners make is to use too fine a sandpaper to
fair. Use 80 grit on a random orbital sander to sand the filler. Then use
a few layers of high build primer, fill any remaining imperfections, and
sand with 150-220 paper before painting. LPU paint is toxic when spray
painted so always use a positive pressure forced air system if spraying.

Hi Evan,

I thank you for your valuable information, but have a question...

(Well, two, now that I think about it g)

Is there a downside to the more durable epoxy+microbaloons approach?
And, also, the substrate is polyester. Can I use epoxy over that? Or
would I be using my resin with the microbaloons?

Thanks again,

--
Kenneth

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