goodbye to original gelcoat?

Ship'sCat

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My 1968 23ft gap sloop has lead a sheltered sort of life and the gelcoat is in good condition in both the white hull moulding as well as the upper moulding for the coachroof and side decks. However the coachroof/side decks moulding has a yuch sort of duck egg green colour. I am not sure if that was the original and the colour has changed over the years but I don't like it. I would much prefer a deep blue (I expect to be sailing in northern climes anyway). I have read various articles on tis site as well as manufacturers info on the methods for painting over a gel-coat. But what I would really like to know is if any readers have painted over their original-in-good-condition gelcoat and regretted it?
 
I don't think Snark's gelcoat was very good but it was painted when I bought her and has been re-painted (Awlgrip both times). I wish the first guy had done something about the gelcoat rather than have it painted over. I'm due too have it done again but it's expensive and in my case unsatisfactory.
 
Hello Ships Cat
As a surveyor painting the original gel coat (particularly the hull) may put many new buyers off simply because they know it ends up an endless maintenance job, many do not try to recover the old original gel coat colour but there are plenty of ways it can be done to recover it.

Also if I find a coach roof or upper hull has been painted my first alarm rings as to why? as many a time it has been done to cover up damage or star crazing etc.

However after using a machine polisher with cutting pastes, polish etc always remember to also wax it finally which will prolong the finish.
 
Thanks. Is there a simple technique to expose the original gel coat colour in a small sample to give a preview of what might be possible instead of painting over?
 
Gel coat should be cleaned first. Try detergent then oxalic acid then acetone for oily dirt. Finally try cutting componund then very fine wet and dry sand paper . Each attack more agressive than the previous try until you either get it clean or give up and paint it. As said paint should be last resort. ol'will
 
Gel coat should be cleaned first. Try detergent then oxalic acid then acetone for oily dirt. Finally try cutting componund then very fine wet and dry sand paper . Each attack more agressive than the previous try until you either get it clean or give up and paint it. As said paint should be last resort. ol'will
Thanks, much appreciated.
 
Hello Ships Cat
As a surveyor painting the original gel coat (particularly the hull) may put many new buyers off simply because they know it ends up an endless maintenance job, many do not try to recover the old original gel coat colour but there are plenty of ways it can be done to recover it.

Also if I find a coach roof or upper hull has been painted my first alarm rings as to why? as many a time it has been done to cover up damage or star crazing etc.

However after using a machine polisher with cutting pastes, polish etc always remember to also wax it finally which will prolong the finish.
Why do say it is endless maintenance? A well applied two pack is far more durable than gelcoat.
 
Gel coat should be cleaned first. Try detergent then oxalic acid then acetone for oily dirt. Finally try cutting componund then very fine wet and dry sand paper . Each attack more agressive than the previous try until you either get it clean or give up and paint it. As said paint should be last resort. ol'will

Try a small patch test using 1500 then 2500 grit wet & dry this could bring back the original colour and leave a shiny surface ready for an application of polish
 
Why a good paint job should ring alarm bells is beyond me. At 40 years old most GRP boats are looking distinctly tired & an original gelcoat is often faded & damaged. You can only cut back & polish so many times & then you simply have no option but to paint as the laminate will be grinning through. A quality paint job should add value.
 
Why a good paint job should ring alarm bells is beyond me. At 40 years old most GRP boats are looking distinctly tired & an original gelcoat is often faded & damaged. You can only cut back & polish so many times & then you simply have no option but to paint as the laminate will be grinning through. A quality paint job should add value.

I'm sorry to disagree, but for me painting grp is the end of the line, my last boat had been professionally painted for the previous owner and although it looked good it didn't last and so had to be repainted 3 times in the last 10 years of ownership, far better to try and restore the colour of the original gelcoat, 40/50 year old boats he relatively thick gelcoats so unless some real hash grinding is used the chances of the grp lay-up being exposed is fairly unlikely.
See the attached images of my current 40 year old boat, original gelcoat, the full image shows after a T-Cut application and wax just before launching, the close-up image shows the depth of the original hull grp colour after some scratch repairs and use of 1500/2500 wet and dry. Haven't yet replaced 'go fast stripe'.

Muntjak on land.jpg Muntjak gel coat.jpg
 
I'm sorry to disagree, but for me painting grp is the end of the line, my last boat had been professionally painted for the previous owner and although it looked good it didn't last and so had to be repainted 3 times in the last 10 years of ownership, far better to try and restore the colour of the original gelcoat, 40/50 year old boats he relatively thick gelcoats so unless some real hash grinding is used the chances of the grp lay-up being exposed is fairly unlikely.
See the attached images of my current 40 year old boat, original gelcoat, the full image shows after a T-Cut application and wax just before launching, the close-up image shows the depth of the original hull grp colour after some scratch repairs and use of 1500/2500 wet and dry. Haven't yet replaced 'go fast stripe'.

View attachment 119177 View attachment 119178

While I agree with you that painting is the last option, a good quality 2 component paint like Awlgrip /craft, Alexseal, International or similar when applied properly should last 10 years, and actually during those 10 years require far less maintenance than gelcoat. In fact I've seen on American forums (where painting seems to be more common) yachts with 15+ year old paint jobs that still look great.
Sounds like the PO went with a cheaper 1 pack paint.
 
I'm sorry to disagree, but for me painting grp is the end of the line, my last boat had been professionally painted for the previous owner and although it looked good it didn't last and so had to be repainted 3 times in the last 10 years of ownership, far better to try and restore the colour of the original gelcoat, 40/50 year old boats he relatively thick gelcoats so unless some real hash grinding is used the chances of the grp lay-up being exposed is fairly unlikely.
See the attached images of my current 40 year old boat, original gelcoat, the full image shows after a T-Cut application and wax just before launching, the close-up image shows the depth of the original hull grp colour after some scratch repairs and use of 1500/2500 wet and dry. Haven't yet replaced 'go fast stripe'.

View attachment 119177 View attachment 119178
In that case the paint must have been rubbish. Although my last boat was steel the two pack was still as good as new after 30 years. Top quality two-pack properly applied will outlast the boat.
 
There are good reasons for painting a grp boat. My boat is blue and was painted in Awlgrip. Before it was first sold. … the surveyor explained to me that some manufacturers prefer to do this to provide a coloured hull as grp has a tendency to go chalky.

The boat belonging to the OP is over 50 years old. I would prepare the surface well and paint with a two pack paint. International Perfection perhaps
 
Certain colours fare better than others, Dark blue, Green & Red will discolour & chalk quickly, paler colours & white less so.
If you have got away with keeping the original gel good well done you! Many boats get ill treated, I remember being asked to polish a boat, when i looked at it someone had caned it hard with an orbital sander, probably with 80 or even 40 grit, the sanding swirls were deep & the undercoat gel was showing through all over in patches. It looked truly dreadful. There was no polishing that mess out. Much to my relief the owner decided to get it sprayed unfortunately they were a cowboy outfit & looked great for a couple of years before failing. It turned out they had used acrylic car paint & buffed it up.
It all had to be sanded off again & done properly at considerable cost.
 
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