Any Tricks For Prepping Very Rough Fiberglass Surface For Paint?

[elaak]

Hello folks,

I got a few lockers that I'd like to put new paint in. Some of them are large with a very corse "roven woving" painted fiberglass finish. I have not found a way to adequately sand the previous painting surface to rough it up for new paint. Whether by machine or hand, I'm only sanding the peaks of the fiberglass texture and leaving the valleys untouched. Its probably 60-80% of the surface that is left un-marked.

Any clever tricks out there for doing this right? Was thinking about blasting it with an abrasive media but I am concerned that this may be too aggressive.

Cheers,
Eric

[GRIT]

If you don't mind the mess, blast it. Just pay attention to what you're doing, and don't take any of the glass off. Baking soda blasting should work ok.

Have you tried this? http://3mcollision.com/products/pain...per-03171.html

Then, when you're done making a mess. Bog it with some thickened epoxy to fill the weave.

If you're not planning on making it smooth, you might find an aggressive primer that will stick to the shiny paint. I'm sure there must be something around.

Good luck.
Paul,

[swansailor]

Since it's previously painted you might try some liquid deglosser. It's stinky, but it will allow the next paint layer to adhere to the substrate.

[zeehag]

raw roving?? i donot like sanding that--i usually place more resin over it. then sand it--make sure ye fair it well so not much to sand. if you were in mxico--ye could buy gelcoat cheapo and finish it out.

[Cadence]

Soap and water with a good scrub brush. Don't make a mountain out of a mole hill. JMHO

[nortonscove]

A quick rub with acetone to remove old protectant and gelcoat at your desire. Smelly but works.

[KiwiKen]

If the fibreglass is unpainted and clean use "FLOW COAT" which is a pigmented polyester resin -

See Link
Applying Flowcoat [Archive] - Ausfish fishing Australia, Australian Angling Forums

[Cheechako]

are you sure it's previously painted? or gel coat? At any rate, the rougher the better I say.
TSP should work for paint prep. They make it in spray cans now. wear gloves , it will burn the hands after a bit.
I would put some thought in what paint to use though, seen old paint flaking off in coin size or bigger pieces before...

[Cadence]

Originally Posted by nortonscove

A quick rub with acetone to remove old protectant and gelcoat at your desire. Smelly but works.

I've used a lot of acetone to remove uncured resin. I don't believe it will do much to remove cured resin, gelcoat or grime which is water soluble. JMHO

[minaret]

I certainly would not apply anything without some tooth first, definitely not with just an acetone wipe or an etch.

Use one of these.

https://www.amazon.com/gp/aw/d/B002P...dqL&ref=plSrch

In whatever grit suits you. It's called a bristle disc.



Failing that use a stiff wire brush. Follow with scotch brite by hand.

[knockabout]

brass wire brush and sugar soap then a scrubbing brush with metho allow to dry then coat with epoxy flow coat / you can find all those things on ebay

[flyingfin]

Rough up with wire brush, then 40 or 80 grit sandpaper, then wipe down with MEK. Don't try to sand roven woving flush, you are wasting your time.

Mix up a combination of resin and fairing compound until you get a stiff batter, then apply with roller. After a few coats, you will have a fairly smooth but rough textured finish, kinda like drywall orange peel.

[KiwiKen]

Originally Posted by knockabout

brass wire brush and sugar soap then a scrubbing brush with metho allow to dry then coat with epoxy flow coat / you can find all those things on ebay

I haven't used epoxy Flow Coat, I have used the polester resin based Flowcoat, with extremely satisfactory results, excellent adhesion and good cosmetic result.
An epoxy based product would give even better adhesion.

The only thing one would need to be sure of it that any previous coating on the surface was sound and unlikely to break away.

[baritt]

Hi guys, let me share my experience with fiberglass painting and staining.

I work for a fiberglass door manufacturer name Nova Doors and we use a water based product called TruCoat for painting and staining our fiberglass doors. It is made specifically for fiberglass so it doesn’t require any special primers, is super durable and lays down really smoothly.

Worth checking! We are super satisfied with it!