Gel coat or Paint?

[Johno]

Hi all,
My friend Luke has ordered a fibre glass kit frm NTS Engineering but without a finished gel coat finish. I am now having second thoughts about having a gel coat finish as well. Luke wants a metallic finish but the thought of being able to fit your GRP kit without worrying about scratching or damaging them seems appealing.
I know from previous posts from Fabby that gel coats fade with time faster than paint.
Does the cost of a gel coat finish against the cost of spraying the parts once finished justify the price?
Basically what I'm asking is it better to gel or paint.

Any opinions on this matter would be greatfully appreciated....

Johno

[MarkB]

Panels will or should be gel coated anyway. If it's for painting then they are usually done in grey or white gel. There is a painting specific gel which is easier to sand but costs a fortune.

If you want a metallic finish then specify the colour you want in gel and pre fit it to your car then once happy with it all flat it off and use metallic clear coat and you have metallic finish from a gel original.....But the original finish needs to be top notch as if just used as a polished finish.

[robo]

I dont think there is a problem with fade. There are three westies running around here which are immaculate, one of them is a dark blue and its got to be 15 years old if its a day as its got an escort axle in the back. All of them still in the gelcoat and no fade. I have seen red bleach before but that was yonks ago and even that polished up ok. They might have escaped it because they are garaged!

Bob

[Wynand]

Originally Posted by robo

I dont think there is a problem with fade. There are three westies running around here which are immaculate, one of them is a dark blue and its got to be 15 years old if its a day as its got an escort axle in the back. All of them still in the gelcoat and no fade. I have seen red bleach before but that was yonks ago and even that polished up ok. They might have escaped it because they are garaged!
Bob

Keeping it out of the sun did help in a big way and perhaps the fibreglass man got things right when making them....

My friend Luke has ordered a fibre glass kit frm NTS Engineering but without a finished gel coat finish.

I think it still has a gelcoat, albeit a clear one applied to have the smooth mold finish, read below.

I work with GRP basically on a daily basis and for years had built boats and other fibre stuff for a living and am on record many times for my mistrust in gelcoat.
I would venture and say as much as 90% of all gelcoats applied to molds are much to thick according to specs and herein lies its danger. Styrene get trapped in the molding because of that and over years (especially when exposed to sun like boats) would surface through the gelcoat hence the fading / discolouring and a common symptom is cracking of the gelcoat and usually starts as little hairline spider web like crack. In severe cases the gelcoat just open up in cracks.

The reason many apply the gelcoat thickly is to get coverage to prevent brush streaks especially with "difficult" colours like red for instance. The best way to apply gelcoat is to spray it on evenly and the equipment for that is very expensive and I would venture and say that no manufacturer doing seven body moldings have this type of equipment.

The reason why gelcoat has to be applied to the mold is to get a smooth surface - laminating directly against a mold result in many small pin holes because of resin not fully saturated through the CSM and is very difficult to repair because of its small size.
The way I did my car's body moldings was to use white gelcoat very sparsely (streaky see through) and just enough to get a smooth surface finish from the mold. These parts were later lightly dry sanded down with aluminum oxide sanding sheets (360#) and two pack epoxy primer and top coats paints applied.

All good two pack epoxy paints are far superior than gelcoats and will outlast it and you obtain a better finish with deep colours if you applied a few coats of colour top coat and optional clear coat applied if you want to go that way. And you can basically have any colour you wish for...

[shh120m]

The panels are being done in white, at a discounted price because im not rubbing out or polishing up imperfections which seems to take forever

[robo]

My advice for what its worth would be to go for a colour and leave it for a year then paint. Grp moves around a lot initially and takes a while to settle down. I made that mistake on a cobra kit and ended up having to repaint it, the main problem areas seem to be around the engine bay so I assume its the heat related.

Bob

[MarkB]

I would opt for a polished gel coat finish, painting for the sake of having it a certain colour isn't carbon foot print friendly don't you know..... Besides the cost of having it painted would get the car on the road so why bother!!!

Some kits don't give you the option of gel finish due to the way they are made but I don't see why as folk like Ultima and GTM make very techy shapes yet they are a polished gel coat finish.

[baz-r]

a bit of a note all epoxy based paints will chalk over time a 2pack polyurthane is a better option it will hold its gloss for much longer use it over a epoxy based primer for best adheasion.
i used to sell this into a co. that worked in refurb and repair of grp products from boats to baths worked a treat on speed boat hulls.
this was all spec'ed buy my ind paints co. and thay made paint of all sorts and types and always got the right product for my customers needs

[Wynand]

Originally Posted by baz-r

a bit of a note all epoxy based paints will chalk over time a 2pack polyurthane is a better option it will hold its gloss for much longer use it over a epoxy based primer for best adheasion.

Actually what I meant by epoxies - I always uses 2 pack Polyurethane / Polyacrythane paints on my moldings and painting boats etc. Locally the guys refer to that as epoxies and is a misnomer. Thanks for pointing it out

[robo]

Car cover when not in use, sorted.

Bob