Best way to restore Gelcoat.

[steveeasy]

The Gelcoat on my topsides has not been touched for years. This winter I would like to sort it. I'm sure there are 100s of expensive products on the market but id like to cut through the chaff and do it once. Ive a polisher and pad. what products would like minded souls use ?. I suspect its a 2 part process of a fine cutting compound then polish. all recommendations appreciated.

Steveeasy

 

[Concerto]

Steve, IIRC you have a Westerly. If this is the case then you are lucky as they used a double gel coat that will be 2 to 3 mm thick. The gel coat has probably turned a creamy colour due to the Ryland gel coat being non UV stable. To get a white hull will mean you have to sand ff the top layer of the gel coat. This is best done with an orbital with a fine grade. I would suggest starting with 600 used wet. Change the sheets frequently as small lumps of gel coat will score deeper marks and require further sanding to remove. Use a plant spray to apply a minimum of water as lubricant. If 600 takes too long then change to 400.

Once the hull is white, you will then need to go through the grades to 1200. To ensure no swirl marks are present, use a Guide Coat paint from Halfords. This thin paint will be sanded off and shows any areas that have scratches left. Then you will need to start using compounds to start to get a shine. I use Farecla G3, followed by G10, on their foam pads on my polisher. Once finished you need to use a high quality UV protecting polish. I use Star Bright Premium Polish. Providing you have the equipment it will cost about £200 in pads, compounds, etc. However it does take a long time. Think about a day per process, i.e. each grit of sanding and compounding.

If you do not have access to a platform, make one or buy one of these. https://www.machinemart.co.uk/p/clarke-sl-2c-4-way-combination-ladder/

Final bit of advice. If you have any deep scratches in the gel coat, these will need grinding out to clean the edges. I use a Dremel. If you do not clean the scratch, it will be edged with a dark line. Then fill with Plastic Padding Gel Coat Filler and sand level. This is an almost perfect colour match to the original gel coat.

 

[coopec]

I made a bit of a mess-up with the painting of my boat. It used to upset me and I related the sad story on a thread I think on this forum. One guy posted a photo of his yacht which was stunning, I asked him how he did it and he said he wet sanded it with something like 600 grit paper (or even higher) but not just once but several times between coats.
You better check it out before you destroy your gelcoat but maybe a wet sand with 1200 grit paper may be the way to go?

Here is just one clip which you may take a look at. (There are several more)
https://www.youtube.com/watch?v=ZexSavaT4tY

 

[Poignard]

Oxalic acid and Zep floor polish.

 

[steveeasy]

oops, think the sanding option scares me. my gelcoat is wafer thin. Twister 28, step ladder touched it yesterday lightly and that scratched through the gelcoat without any weight on it at all.

Steveeasy

 

[johnalison]

There's no harm in doing a trial patch with cutting compound, but I would start with a fairly harsh one. As #2 says, this may not be enough and his method will be needed. It will be a terrible job if you don't do as he says and use a platform.

 

[lw395]

Find one of the deeper scratches on the boat, there usually are some!
That will show you the gel coat is reasonably thick in that area I hope.
Try a fine grade of wet and dry paper, wet.
If the surface is quite scratched in general, you might start with 600.
Work finer to 2000, 3000 or 4000.
Then reach for the polishing compound.

You can waste many, many hours starting too fine.
Experiment, see what works.
Sometimes it's mostly dirt and surface which will come off with tcut. Mixtures of old wax, grime etc.
Sometimes fading, chalking, UV degradation goes many microns into the surfaces and you need to remove that layer.

At some point you need to decide what scratches you will fill, which you will polish out and which you will live with.
On an older boat it is a balance, how much effort you want to put in, how well can you match new gel coat, do you want immaculate or just 'looks a lot better when photographed'.

 

[NOHOH]

Poliglow/ Newglass2 does a very good job and is completely reversible.......and....because you are not abraiding your gelcoat....you are not, like many of the other products, making your gelcoat thinner...but adding something to it.... Google and look at the videos....the results are impressive

 

[lw395]

Poliglow/ Newglass2 does a very good job and is completely reversible.......and....because you are not abraiding your gelcoat....you are not, like many of the other products, making your gelcoat thinner...but adding something to it.... Google and look at the videos....the results are impressive

That will only work if the gelcoat hasn't changed colour and isn't stained or scratched much.

 

[KINGFISHER 8]

If you're wet sanding with a machine you might bear health & safety in mind! … :encouragement:

 

[Poignard]

oops, think the sanding option scares me. my gelcoat is wafer thin. Twister 28, step ladder touched it yesterday lightly and that scratched through the gelcoat without any weight on it at all.

Steveeasy

This yacht is 52 years old. I have owned her for 22 years.

The hull has not been sanded.

The hull does not look like new but it is white and fairly shiny. For a boat that old it looks fine, especially when on the water, where she belongs.

The hull was whitened by applying oxalic acid.

The shine comes from a few coats of Zep Commercial Floor Polish, wiped on and left to dry.

There is nothing else to do. It dries with a shine.



https://www.screwfix.com/p/zep-comm...tr/2904j#product_additional_details_container

 

[Hydrozoan]

I think it would help if the OP said more specifically in what way/s he thinks the gelcoat on the topsides ‘needs sorting’. Is it scratched, apparently yellowed or otherwise changed in colour (uniformly, or patchily), etc? In general I would advocate non-abrasive cleaning before embarking on anything more vigorous, but more information would I think be helpful.

 

[Marine Reflections]

The Gelcoat on my topsides has not been touched for years. This winter I would like to sort it. I'm sure there are 100s of expensive products on the market but id like to cut through the chaff and do it once. Ive a polisher and pad. what products would like minded souls use ?. I suspect its a 2 part process of a fine cutting compound then polish. all recommendations appreciated.

Steveeasy

Hi,

As others have warned, don't reach for anything yet until you can determine the thickness of your gelcoat.
Evaluating the surface and forming a game plan is probably the most important stage.

Reading that your ladders lightly touched the surface and scratched through the gel coat is a concern. Are you sure it went through and not just left a mark?
If it went through with such little effort then I'm afraid you could be out of the sanding / polishing options and possibly more into the painting / re-finishing options.

Are you positive it is indeed gel coat and hasn't had a coat of paint in its life?

Some very close up pictures in focus would help us help, any possibility?

Tony

 

[NOHOH]

That will only work if the gelcoat hasn't changed colour and isn't stained or scratched much.

The `prep solution` with this product is excellent at cleaning `whatever is there` on your hull....and then....the treatment applies 5 or 6 coats of a milky coloured liquid that enhances the colour of your original gelcoat....Its put on using an applicator supplied in the kit...and it goes on very quickly. After the third coat it all looks a bit dreadfull...but then with the 4th and 5th coat it all starts to even out, shine , and look like new fibreglass...Just try it.......as I said before...its completely and easily reversible if you don`t like the results....and its really not expensive

 

[steveeasy]

Hi,

As others have warned, don't reach for anything yet until you can determine the thickness of your gelcoat.
Evaluating the surface and forming a game plan is probably the most important stage.

Reading that your ladders lightly touched the surface and scratched through the gel coat is a concern. Are you sure it went through and not just left a mark?
If it went through with such little effort then I'm afraid you could be out of the sanding / polishing options and possibly more into the painting / re-finishing options.

Are you positive it is indeed gel coat and hasn't had a coat of paint in its life?

Some very close up pictures in focus would help us help, any possibility?

Tony

Hi Tony,
The hull is over 50 years old. It is the original gelcoat. When the step ladder left a mark I assumed it had gone through the gelcoat. on reflection it may well have been a mark left by the step ladder. The finish is very good considering it has not been polished in 10 odd years. I have two areas damaged by impact. the plan was to restore the original colour of the topsides then repair the 2 areas that have penetrated the gelcoat to match the final colour.

I believe the gelcoat is slightly discoloured and has some slight yellowing on above the waterline in places. No chalking at all just a little flat.

All the rest of the advise is very much appreciated.

Steveeasy

 

[Stemar]

Oxalic acid mixed with wallpaper paste will get rid of the yellowing. Y10 will also do it, but you can get a lifetimes supply of oxalic acid and paste for the price of a tin of Y10.

Just remember, both Y10 and the home brew are toxic and irritant, so wear gloves and eye protection.

 

[steveeasy]

Oxalic acid mixed with wallpaper paste will get rid of the yellowing. Y10 will also do it, but you can get a lifetimes supply of oxalic acid and paste for the price of a tin of Y10.

Just remember, both Y10 and the home brew are toxic and irritant, so wear gloves and eye protection.

cool, ill give it a try.
thanks
steveasy

 

[pvb]

cool, ill give it a try.

Do make sure you're well protected, oxalic acid is nasty stuff. I use Y10, despite the slightly higher cost - a small tub lasts for ages and ages, is neat and convenient, and I can't be bothered with faffing around with wallpaper paste!

 

[coopec]

This article came through to my email inbox. I haven't read the article yet but it does seem to be relevant.

https://www.practical-sailor.com/pp...s=p_GelcoatRestoration111119&product_id=11433