Cockpit GRP cleaning

[Straightman21]

I've searched around but no clear answers although I'm sure it has been asked before. The white [almost] GRP around the cockpit is very slightly tired and has scuff marks etc. What is the best to clean / brighten it up please? Many thanks.

 

[Deleted member 36384]

I have a grey gelcoat in my cockpit, dull and tired looking. I gave it a wash with detergent and warm water, then when dry, polished with 3M™ Perfect-It™ Gelcoat Medium Cutting Compound + Wax. It was simply wiped on with one cloth, about a 1-2 square feet at time, just by hand and firm pressure, then with a different cloth buffed up to a polish. It worked exactly as the description below from the web site. I did that last year and it's still looking good.

https://www.3m.com/3M/en_US/p/d/b40065580/

An Excellent Gelcoat Finish in a Single Step
For a truly professional gelcoat finish, our Perfect-it™ Gelcoat Medium Cutting Compound + Wax combines fast cutting compound and a durable shell for the surface in one step. Its premium chemical and mineral formula quickly removes oxidation, weathering, dulling, chalking and scratches as coarse as P1000. It leaves a high gloss wax finish. The compound, which is suitable for environments not sensitive to silicone, quickly restores the beautiful luster to scratched and oxidized boat surfaces. It leaves an excellent finish in one step. The compound also has a long wet time, allowing you to compound longer before you need new material. You use less product even in warmer climates, yet it handles well and does not clog on the buffing pad. The formula also includes a wax coating which helps protect the compounded gelcoat surface from the elements and reduces the need for further polishing or waxing.

 

[Concerto]

This PowerPoint presentation I made covers what to do with gel coat on older boats, especially Westerly.
https://wiki.westerly-owners.co.uk/images/8/86/Gel_coat_renovation_19May2020.pdf

 

[William_H]

GRP around the cockpit is either non skid or smooth. Treat smooth like top sides. Non skid is more difficult and needs a stiff brush. Discoloration (contamination) comes in various forms. Mold is treated with bleach. Oil is treated with detergent then acetone or similar. Other stains are often moved with oxalic acid.
So trick is to start with detergent and perhaps pressure was. Then assuming you don't know what contaminant is try oxalic acid bleach or acetone. Then lastly if necessary you may get an improvement with very fine wet and dry sand paper and or cutting compound. Not much you can do with non skid rough areas.
In the end you paint it all. But make that a very last resort. ol'will

 

[Refueler]

Cilit Bang Lime and Rust remover to get it reasonably clean ...

Then if stubborn stains remain - then mix up Oxalic Acid with hot water ... let cool ...... add wallpaper paste .....

Now wet all surfaces and let loose water run off ... then paint on the Oxalic mix ...

Leave for a while .. I like about 10 mins ..... then wipe off ... then wash with water .....

Note : I found the general ratio of Oxalic to water to be weak - so I doubled the ratio and then it did the job.

If you want to try a quickie cheap route ... try Toilet Cleaner such as Harpic .. squirt on ... brush it all over ... leave and then wash off.

 

[Slowboat35]

How about trying traditional Jif before resorting to brutal products like cutting compound or, God forfend, wet and dry...? You're very likely to find you don't need a sledgehammer to crack that particular nut.

 

[Stemar]

Magic sponges are good for this - Milady swears by them. You can get cheapies on Amazon and fleabay, but you go through 'em a LOT quicker. A bit of cream cleaner on one brings most things up clean. Won't do anything about scratches, though. If there's enough gelcoat left, I'd rub them down with as fine a sandpaper as you can get away with, then polish. I ended up painting everything, but my boat's 50 years old.

 

[Deleted member 36384]

... The white [almost] GRP ...

I recall a claim from a forum member, when this was discussed, that lemon cleaning powders such as Jiff / Ciff can leave a hint of yellow staining on white gelcoat. If the gelcoat is dull it could be due to grime and the washing only may bring back the shine. If it does not, then you have to abrade the gelcoat to get it to shine.

Vim / Ciff uses a clay material for the abrasive property at 2 microns grit size, the 3M is 5 microns for 1000 grit size, neither are "brutal' as suggested above.

What you do need to be careful about is wearing through gelcoat. My boat at 43 years old, has quite thick gelcoat at about 1mm, other boats have thinner gelcoat.

Saltwater boat shampoos such as Starbright Boat wash, which I used this weekend on topsides, worked very well at getting rid of grime and bringing out the colour, so this should be your first action. However, my gelcoat just drys flat and dull, so it does need the abrasive treatment.

 

[lustyd]

In the end you paint it all. But make that a very last resort. ol'will

Agree with this, but the last resort is only after several years of looking at it in poor condition, and preferably days before you sell the paint maintainance nightmare you've created!

 

[Pete7]

Saltwater boat shampoos such as Starbright Boat wash, which I used this weekend on topsides, worked very well at getting rid of grime and bringing out the colour, so this should be your first action. However, my gelcoat just drys flat and dull, so it does need the abrasive treatment.

By chance this weekend I found a bottle of this stuff on board long forgotten. paired with one of those green pan cleaning pads it did a really good job of cleaning the topsides. A coat of wax polish on top produced a good shine for the time spent on it.

In the end you paint it all. But make that a very last resort. ol'will

Whilst I was busy polishing, some lads were wrapping a nice 40ft yacht with a silver plastic skin. Looked a neat alternative.