Painting topside on a GRP hull - best roller method?

[conks01]

Hi,

I've used an Epifanes enamel high gloss paint (Bootlak) which appears a fairly decent enough paint but despite rolling (sponge) and tipping (3 inch brush) the finish is poor.

I've got to say that I'm disappointed with it.

From a distance it looks fine but when close up you see orange peel and the odd roller 'edge' mark.

I have cut back in between coats with 400 grit and have attempted to flatten without much success.

The paint build up was:

1. Primer / Undercoat - 2 coats.
2. Epifanes Bootlak high gloss enamel - 4 coats.

Where I believe I've gone wrong was in the primer/undercoat. I think I didn't sand and flatten enough before applying the finishing gloss coats.

I'm wondering if there's anything I can now do to remedy it? - Maybe get heavy with the sanding, use a cloth roller rather than a sponge roller (the roll & tipping didn't go too great either !) ?

All advice greatly appreciated.

Thanks.

 

[Tranona]

You have maybe put far too much paint on. The trick is to get the undercoat absolutely perfect, clean it with a tack rag and 2 top coats. Four is overkill and every additional coat emphasises any imperfection. Flatten it right off, to remove all the runs, orange peel ridges etc and try one more coat just by brush. Roller and tip off needs two co-ordinated people with a deft touch. I find a high quality 2 1/2" brush on my own gets best results - for me!

 

[conks01]

You have maybe put far too much paint on. The trick is to get the undercoat absolutely perfect, clean it with a tack rag and 2 top coats. Four is overkill and every additional coat emphasises any imperfection. Flatten it right off, to remove all the runs, orange peel ridges etc and try one more coat just by brush. Roller and tip off needs two co-ordinated people with a deft touch. I find a high quality 2 1/2" brush on my own gets best results - for me!

Great. Thanks. I'll give it a try. Can't make it any worse!

 

[zoidberg]

The trick is to get the undercoat absolutely perfect, clean it with a tack rag and 2 top coats. Four is overkill Roller and tip off needs two co-ordinated people with a deft touch. I find a high quality 2 1/2" brush on my own gets best results - for me!

Hmmmm.

All this fine weather has me peering at the off-white 40 year-old original GRP gel-coat hull of my favourite project, and visualising it in a deep, glossy carmine red. Who would help me renounce temptation? Or, point me towards yet another DIY disaster......?

 

[ghostlymoron]

If it were me, it would look worse after painting. I'd try cutting and polishing provided it's not too dented. My experience of rolling and tipping is similar to the OPs ie disappointing. Each coat needs to perfect, my primer was slightly orange peel and I assumed the top coat would fill the depressions - needless to say, it didn't.
Maybe rub it down again to expose the primer and apply two topcoats rolling and tipping. Perhaps do a test run on the transom where it won't show too much.

Hmmmm.

All this fine weather has me peering at the off-white 40 year-old original GRP gel-coat hull of my favourite project, and visualising it in a deep, glossy carmine red. Who would help me renounce temptation? Or, point me towards yet another DIY disaster......?

 

[Tranona]

Hmmmm.

All this fine weather has me peering at the off-white 40 year-old original GRP gel-coat hull of my favourite project, and visualising it in a deep, glossy carmine red. Who would help me renounce temptation? Or, point me towards yet another DIY disaster......?

Can be done outside, but a bit hot at the moment as paint will dry too quickly. My old boat has to be painted because it is cascover sheathed ply and get that deep glow with Toplac 105 (dark blue) and it lasts many years. You just have to write off a few days doing the prep and applying the top coat only takes a couple of hours in the right conditions.

 

[lw395]

The issue is for the man with the brush to be familiar with the paint, tools, temperature, situation.
The first time you paint a yacht it will be horrid. Get some practice in, or do the prep and get an expert in.
It might be cheaper to get an expert in for a morning than to waste paint.
If you must DIY practise on some doors or something.

FWIW, foam brushes and Dulux gave me the best result I've ever achieved. A really thin coat that hardened quickly, it lasted very well.

 

[burgundyben]

In this weather you are up against, soon as the sun is up and the dew is dried off, it'll be getting warm, you'll have even less time.

Ideally you want to wet sand all the imperfections out, then add something to the paint to slow it down, give you more time to tip it off, get someone else to do the rollering while yo tip off.

I find a Hamilton Perfection brush very good.

 

[TQA]

The key to roll and tip success is getting the thinning right. Here is one method.

Get a piece of glass at least a foot square, wipe it clean with acetone and set it near vertical.

Take some paint and add a little thinner [use a measure] roll and tip on the glass.

If it sags you have too much thinner if the brush strokes do not flow out you have too little. You will know when you get it right. If it is hot you will need slow thinner sometimes called brushing.

Wipe glass off with acetone between trials.

If conditions change as you apply you may need to adjust the thinning.