Board logo

Painting new GRP
David Jenkins - 6/7/04 at 12:18 PM

Yes, it's painting GRP time again!

I will shortly be painting a nice new shiny bit of GRP (no repairs - a virgin surface). The final coat I want to put on is cellulose - I've already got it, and the colour matches my existing GRP perfectly.

Presumably I need to 'wet & dry' the gelcoat slightly to get a matt surface, using very fine paper. Should I have to follow this with a special primer, or will the usual stuff be OK?

rgds,

David

[Edited on 6/7/04 by David Jenkins]


Peteff - 6/7/04 at 12:46 PM

I painted my nosecone after I hit my bike with it, I just did same as when I paint anything else, rub down with 800 or 1000 wet and dry to take the shine off. I primed it with a few coats of ordinary celly primer and flatted it with 2000 grit then gave it a few topcoats. I like cellulose as it's more forgiving. Make sure you wash your hands first or use surgical gloves as you can easily contaminate the surface if you have oil or grease on your hands and may end up having to use isolater which is dearer. Mark Allanson's the one to get on the case for this job I think

[Edited on 6/7/04 by Peteff]


Hugh Paterson - 7/7/04 at 09:03 AM

I use Awlgrip on punters boats on request, I use epoxy hibuild primers from the automotive world on my own stuff. works fer me Nowt wrong with good old cellulose though, as long as u make sure that you have removed all the wax or release agent that tends to cling to fresh grp yer cooking. Dont you just luv the smell of cellulose, everyone needs a fix now and then
Shug.

[Edited on 7/7/04 by Hugh Paterson]


Mark Allanson - 7/7/04 at 04:11 PM

If you are using celly, you can buy aerosol etch from automotive paint suppliers, quite cheap and aesy to use - don't try and put it on too heavy, a couple of dust coats will do it. remember it is only to provide a good cohesive layer, not for transparency coverage.


David Jenkins - 7/7/04 at 06:29 PM

Mark,

Is that a special etch primer, or the normal acid etch primer for metals?

rgds,

David


Mark Allanson - 7/7/04 at 07:26 PM

I haven't looked at the composition, but we use it on all the small jobs that don't justify a separate bake for the etch - excellent stuff, never a problem and we do a lot of ally bodied cars, and plastic panels


NS Dev - 7/7/04 at 11:18 PM

yep, not an expert on painting but the activated cellulose etch primer (that's what I got when I asked for "cellulose etch primer" sticks like the proverbial to seemingly any surface (desired or not!) and is a great key for the later celly coats!


thekafer - 8/7/04 at 02:42 AM

Always wipe a new part down with a solvent before sanding. If the manufacturer does'nt remove whatever mold release he used you will sand it INTO your part!!!

Fletch,


David Jenkins - 8/7/04 at 07:26 AM

quote:
Originally posted by thekafer
Always wipe a new part down with a solvent before sanding. If the manufacturer does'nt remove whatever mold release he used you will sand it INTO your part!!!



That's logical when you think about it... thanks, Fletch!
(this is one of my weekend jobs, if the current high winds & rain don't wreck the house! )

David


marc n - 8/7/04 at 07:49 PM

panel wipe the parts first then using a scotch brite should suffice on the preparation front, as long as the fibreglass is good quality, we normally then go over with panel wipe five or six times before painting,

regards

marc


David Jenkins - 9/7/04 at 07:35 AM

Unfortunately the GRP is not best quality - it's going to need a bit of filling here and there, plus a bit of 'restyling'.

Can you get panel wipe in small quantities, or will cellulose thinners (Xylene) do the job? I've already got some of that! Or will it attack the GRP surface?

David


timf - 9/7/04 at 08:32 AM

david if you want a small quantity i can decant you some into a jar if you want
i have a 5l tin in the garage