Applying new gel coat - tips and tricks?

B

BoatingBeginner

Well-Known Member
Joined
29 Mar 2010
Messages
157
Visit site
My boat's white. Always has been. As a 'Nelson' type boat, though, it looks daft in white - and I want to make it navy blue. Of course, I thought about painting, but given the time involved in preping (the rubbing strakes and skin fittings are being removed anyway), I'm tempted to try applying a couple of fresh coats of gel coat instead of paint.

Can anyone suggest any tips or tricks?
 
BoatingBeginner said:
My boat's white. Always has been. As a 'Nelson' type boat, though, it looks daft in white - and I want to make it navy blue. Of course, I thought about painting, but given the time involved in preping (the rubbing strakes and skin fittings are being removed anyway), I'm tempted to try applying a couple of fresh coats of gel coat instead of paint.
Click to expand...

Don't you think you'd need to prep before applying gelcoat? This is not a DIY job - get it professionally painted with Awlgrip.
 
Sorry - I meant... given that I'll be prepping anyway - I'm not thinking to apply gel coat as a means not to prep!!

If I had the money to get a professional Awlgrip finish, I would!
 
BoatingBeginner said:
Sorry - I meant... given that I'll be prepping anyway - I'm not thinking to apply gel coat as a means not to prep!!

If I had the money to get a professional Awlgrip finish, I would!
Click to expand...

OK, understand now. You'll find it much easier to get a decent DIY finish with paint than with gelcoat.
 
Thanks - but why is a two-pack paint job that much easier than applying gelcoat? I like the idea of a hard coating I can rub back to an authentic-looking lustre - if only I had the confidence to do it!
 
Many, many, many years ago, I built plywood boats. One of my creations I decided to sheath the hull in woven glassfibre. Worked a treat albeit with some proviso's.

1. The hull was small enough (20 ft)to apply the final coat in one go by roller. As resin goes off in 10 minutes or so, it would be difficult to do this on a larger hull. Consequently I image the 'joins' would show (badly).

2. As the hull I treated was inverted, runs and drips were at a minimum. Can't see you getting a very good finish 'right way up'.

3. Although the finish seemed to last ok, all glassing was done in a few days. To get a new gel coat to adhere successfully to an on old, fully hardened gel coat takes not inconsiderable effort. Ideally the surface needs to be 'softened' as well as sanded etc.

4. I doubt the application of a single gel coat would give good coverage of the old colour anyway.

I'd say use paint if you must.
 
I'm getting my head around the basics at last! The idea of covering it up or adding wax to the final coat is counter-intuitive.

It's certainly much cheaper than Awlgrip, and cheaper than most yachtie two-pack paint, so it's a wonder it's not done more often.

I know painting is all about maintaining a wet-edge, but is it the same with gel coat? If it stays tacky if left uncovered, then surely this isn't a problem - which is lucky as I've got about 10 square metres each side so with a pot life of 10 minutes I'd be lucky to do a side in one go...
 
Gelcoat is designed to be applied to a mould, and is meant to set anaerobically, with its surface finish being provided by the waxed, polished surface of the mould. Gelcoat used as a paint will always dry with a slightly sticky surface, unless some wax in solvent - usually styrene - is mixed in with it - this will bloom to the surface, seal it off and allow it to dry non-sticky; unfortunately, some of the wax may also migrate to the other surface, giving less than perfect adhesion, and the outer surface finish won't be very smooth or even. This technique is OK for small areas; for an entire hull, it is likely to be a disaster.
A good paint finish, with meticulous surface preparation and good quality 2-pack paint, is much more likely to give a satisfactory result.
 
greenalien said:
Gelcoat is designed to be applied to a mould, and is meant to set anaerobically, with its surface finish being provided by the waxed, polished surface of the mould. Gelcoat used as a paint will always dry with a slightly sticky surface, unless some wax in solvent - usually styrene - is mixed in with it - this will bloom to the surface, seal it off and allow it to dry non-sticky; unfortunately, some of the wax may also migrate to the other surface, giving less than perfect adhesion, and the outer surface finish won't be very smooth or even. This technique is OK for small areas; for an entire hull, it is likely to be a disaster.
A good paint finish, with meticulous surface preparation and good quality 2-pack paint, is much more likely to give a satisfactory result.
Click to expand...

Yes - I was wondering how they got the wax to migrate just to the outer surface... clearly, then, it doesn't!
 
Is the plan to use Gel-coat?

I heve seen areas painted with Flow-coat and the finish was impressive, seems that you might have the two confused.

Gel-coat is supplied without wax mixed in.

Flow-coat is supplied with wax in the mix.

Flow-coat can applied with a spray gun, brush or foam pad.

I saw a couple repaint the cockpit of a 30 footer in an afternoon using foam and brushes, that applied two thin coats and looked like new, they planned to add another coat the next day, I would have been happy with the results they got on day one but they wanted more depth so it would last longer.

Good luck and fair winds. :)
 
Definitely gel coat, not flow coat.

I think I've learned enough to feel confident about tackling the tatty corners on the superstructure. It might save having to repaint the superstructure, too.

I've just been cleaning the hull's gel coat with a solution of oxalic acid and wallpaper paste - the results are dramatic, and I can see how easy it would be to have the gel coat looking like new - if only I was keeping the hull the same colour...!
 
BoatingBeginner said:
Definitely gel coat, not flow coat.

I think I've learned enough to feel confident about tackling the tatty corners on the superstructure. It might save having to repaint the superstructure, too.

I've just been cleaning the hull's gel coat with a solution of oxalic acid and wallpaper paste - the results are dramatic, and I can see how easy it would be to have the gel coat looking like new - if only I was keeping the hull the same colour...!
Click to expand...
Pros can do it in a dedicated boatshed with all the gear, for £many thousands, but even then, the recommendation is paint.
You can of course do repairs with gelcoat, but I wouldnt try the whole boat, as I doubt you will ever get it smooth again. It certainly isnt DIY.
PBO extra magazine had a few pages on how to paint. results looked good, but even then it wasnt a simple job.
 
BoatingBeginner said:
I think I've learned enough to feel confident about tackling the tatty corners on the superstructure.
Click to expand...

Well at least if you do just that at first you may realize just how hard it will be to do the whole hull. Experience is all with this stuff. I agree re-gelling the hull sounds like a good idea, I've often wished it could be done successfully, but having used literally TONS of the stuff in my lifetime, I certainly wouldn't attempt what you're proposing.

Good luck anyway, it's your boat your choice. You could knock thousands off its value, and probably will I suspect. Just my opinion of course.
 
Davegriff said:
Well at least if you do just that at first you may realize just how hard it will be to do the whole hull. Experience is all with this stuff. I agree re-gelling the hull sounds like a good idea, I've often wished it could be done successfully, but having used literally TONS of the stuff in my lifetime, I certainly wouldn't attempt what you're proposing.

Good luck anyway, it's your boat your choice. You could knock thousands off its value, and probably will I suspect. Just my opinion of course.
Click to expand...

Thanks - yes, I'm trying to add future value by changing the colour.

Maybe I'm subconsciously associating painted GRP hulls with grotty tenders from twenty years ago - with peeling, faded paint and nasty brush strokes - but it seems paint technology has moved on. Indeed, many new GRP boats are painted from new I now discover...
 
BoatingBeginner said:
Thanks - yes, I'm trying to add future value by changing the colour.

Maybe I'm subconsciously associating painted GRP hulls with grotty tenders from twenty years ago - with peeling, faded paint and nasty brush strokes - but it seems paint technology has moved on. Indeed, many new GRP boats are painted from new I now discover...
Click to expand...

Except in the case of an irredeemably faded/damaged gel-coat, painting or other resurfacing will probably reduce the value. If the existing gel-coat is in good condition, then painting - even to improve the aesthetics - will reduce the value. I would be hesitant about a repainted boat; I'd wonder what they were trying to hide! But there comes a point where the gel-coat can't be restored to it's original looks, and at that point, painting makes sense.

Given what people have said about the impossibility of getting a good finish with gel-coat, I wouldn't consider it at all, and probably wouldn't consider buying a boat to which it had been done. Again, I'd wonder what was so wrong that was being hidden!

It is also worth remembering that your concept of what makes a boat look good may not be everyone's; white tends to be universally acceptable!

Finally, a coloured layer on white will show any scratch or abrasion VERY prominently as the white shows through the dark paint.
 
You must log in or register to reply here.

Share this page

Top