Guitar Paint question

[JoeShadbolt]

Hi folks, i'm doing my final major uni project, i've made a precussion instrument made from fibre glass, and i've looked to guitar paints to spray it up so the question is how will nitrocellulose of cellulose paints react with the fibre glass.
thanks joe

[des mcneill]

Hi,
Shouldn't be any problem but an etching primer is a good idea but not essential.
Des.

[JoeShadbolt]

Thanks Des, I did wonder about an etching primer but didn't know how well thAt would work with fibreglass. It's a new territory for me cheers

[des mcneill]

Hi Joe,
The paint will not damage the glass fibre and will bond quite well provided the surface is rubbed down with fine "wet & dry" first to provide a key. If you anticipate a lot of flexing the etching primer will help deal with that, otherwise an ordinary cellulose primer does a fair job and is a lot cheaper.
Des.

[Graylion]

Hi Des - you don't mean isolating primer do you? Etching primer is for steel surfaces - I restore old bikes and cars and use it. "Glass fibre" is mis-named as it's really "Glass-reinforced plastic", with the accent on "PLASTIC". Now I know from experience that cellulose-based paints can dissolve many plastics so I would be VERY wary of using it straight onto GRP. I guess you've had direct experience of this though? Best thing is to always test a piece that's out of sight. The easiest way would be to use a dab of cellulose thinners and see what the reaction is. Cellulose is very unforgiving stuff when used on a reactive surface - I've found that out to my cost too! Old cars that you thought would have originally been painted in cellulose weren't! Many manufacturers gave it up in the late 1960s and early 1970s. The same goes for guitars. I had assumed that early 1960s Burns were cellulose painted! NOPE! WRONG! I found that out when spraying one with what turned out to be a cellulose clear lacquer! Watch out for paint curling up!!

[des mcneill]

Hi Lionel,
You are right that Glass fibre really means GRP,either pollyester or epoxy,likewise you are correct that you don't want to paint cellulose over other paints without checking but If used on an unpainted moulding as I understood was the case it will do no harm. Although I seldom use cellulose nowdays I have used it for many years on lightweight GRP mouldings,usually with ordinary cellulose primer,but occasionlly also with etching primer when the need arose. I have wondered if the paint description is correct,but I have painted many types of paint on GRP without any adverse effects,so no worries.
Des.

[JoeShadbolt]

thanks for all the advice guys i'm sure i'll have some pictures up when the jobs finished, regards joe