Can I return yellow gelcoat back to white

[jenkotvr]

My recently purchased boat seems to have quite a bit of yellowing to the gel coat, can this be restored back to white?

Ive tried the likes of t-cut etc but it seems the colouring is underneath the top coat

[tank slapper]

You might have some success with a gel coat restorer, but if it is fairly old then the surface has probably gone and it won't last before it discolours again. The only other option is to have it sprayed, which can end up looking very nice, but is obviously fairly costly.

Edit - if it is waterline discolouration from weed growth, then International do a cleaning gel which is very good for getting that off. Other detergents don't seem to shift it at all.

Edited by tank slapper on Sunday 3rd April 18:07

[jenkotvr]

tank slapper said:

You might have some success with a gel coat restorer, but if it is fairly old then the surface has probably gone and it won't last before it discolours again. The only other option is to have it sprayed, which can end up looking very nice, but is obviously fairly costly.

It's '2000' so not that old. The discolouration appears to be internal hence T-cut wont touch.

I'll look into the restorer thanks

No its not waterline but on the deck; sun 'bleaching' I would suspect

[Simpo Two]

While it's not the 'done' thing to paint over gelcoat (unless it's worn down to the matting), it's quite normal to paint decks with deck paint.

[Searider]

Is it patchy, or a general discolouration?

Has the boat been in the med?

What boat is it?

[jenkotvr]

Searider said:

Is it patchy, or a general discolouration?

Has the boat been in the med?

What boat is it?

General discolouration i'd say towards aft section; other areas seem ok

No its not been to the Med

Its a Fletcher 17 GTO

[Rum Runner]

Starbrite hull cleaner...sponge on then wash off. Most discolouration around the waterline goes yellow. You can buff with compound for ever or 2 mins off on with the acid...

[MOTORVATOR]

Jenko Try this first.

http://www.bosunslockerchandlery.co.uk/61/Y10-Fibr...

Basically oxalic acid, if that doesn't work forget all the other stain removers as they use the same method just not as effective. Make sure you wash it thoroughly afterwards and then wash it thoroughly afterwards again as you won't get it all the first time.

Other than that gelcoat can take a fine (1500) wet and dry over the surface to take it back to a fresh surface and then rebuff with Farecla G3. Not as much work as you might imagine with a machine but keep plenty of water with it to stop overheating a single spot.

In either case make sure you get a damn good coat of polish back on it or you will be back to square one in a short time.

[Searider]

If it's on the deck then it's unlikely to be "staining" - so oxalic acid based cleaners are unlikely to work. No harm in trying though. Y10 is a product that although expensive for what it is, is easy to use.

I'd suggest machine polishing.

[tank slapper]

Simpo Two said:

While it's not the 'done' thing to paint over gelcoat (unless it's worn down to the matting), it's quite normal to paint decks with deck paint.

No reason why you can't do it, but it needs to be done properly with 2 part paint or it won't last. These two pictures were before and after - the big patches are an old gelcoat repair and are particularly pronounced there as it was very cold and the colour match varied with temperature for some reason. The reason for the paint job was to fix all the small marks, which were caused when a smaller boat clashed against the side as its mooring was too close.

Before:



After:

[Jackleman]

The best product I have found for doing this is called Y10 and contains oxalic acid.

[Rum Runner]

You get staining around the the waterline and UV damage, as said Starbrite will bring all of this out. If the gel-coat is a of age and beyound simply to discoloured then repaint will be needed.

[don4l]

Another thumbs up for Y10 from me.


It is best to avoid automotive products like T-Cut. They contain ammonia which encourages blooming (as I learned to my cost).


Don
--

[Kneetrembler]

Searider said:

If it's on the deck then it's unlikely to be "staining" - so oxalic acid based cleaners are unlikely to work. No harm in trying though. Y10 is a product that although expensive for what it is, is easy to use.

I'd suggest machine polishing.

+1

[Rum Runner]

don4l said:

Another thumbs up for Y10 from me.


It is best to avoid automotive products like T-Cut. They contain ammonia which encourages blooming (as I learned to my cost).


Don
--

Y10 is slow...To be quite honest the best is Osphro http://www.jamestowndistributors.com/userportal/sh... but it is hard to get hold of here.

Or similar product, with good pictures to explain what I am talking about I guess. http://www.deckhandmarine.com/chine-shine-reviewed...

[Simpo Two]

I dont know if it's suitable for the marine environment, but inland types with GRP hulls seem to rate Poliglow highly (for polishing not cleaning that is)

[Jackleman]

Rum Runner said:

Y10 is slow...To be quite honest the best is Osphro http://www.jamestowndistributors.com/userportal/sh... but it is hard to get hold of here.

Or similar product, with good pictures to explain what I am talking about I guess. http://www.deckhandmarine.com/chine-shine-reviewed...

Y10 is not slow if you use it in the right temperature conditions, normally restores the gel back white in a couple of minutes.

[MOTORVATOR]

Jackleman said:

Rum Runner said:

Y10 is slow...To be quite honest the best is Osphro http://www.jamestowndistributors.com/userportal/sh... but it is hard to get hold of here.

Or similar product, with good pictures to explain what I am talking about I guess. http://www.deckhandmarine.com/chine-shine-reviewed...

Y10 is not slow if you use it in the right temperature conditions, normally restores the gel back white in a couple of minutes.

Yep hour and a half to do a 34 foot Sunseeker top, sides and arch using a pot and a half so fifteen quid. hardly expensive. Hardest part is washing down afterwards if it's a bit sunny as it dries quicker than you can get back to it.

Tried all the Starbrite products and wouldn't go near them. Overpriced rubbish cleaners that justify it because it has marine written on it.

If you want to do it really cheap just go and buy the oxalic acid yourself and knock it together with a gel or paste. It's just the same.

Sometimes we just pay through the nose because we believe a boat is different to a car etc.

Top tip for cleaning your vinyl seats? No not Starbrite or marine this or that, just use biological washing fluid and hot water and watch the dirt fall off to leave them brilliant white incuding the grain and stitching!

[MOTORVATOR]

Simpo Two said:

I dont know if it's suitable for the marine environment, but inland types with GRP hulls seem to rate Poliglow highly (for polishing not cleaning that is)

Boat's no different to your car really John. Time is best spent compounding and finishing the surface first then it doesn't really matter if you use a wax or one of the polymer items.

Best wax I've ever used on a boat is Waxing Frenzy made in the states. http://www.hammerheadboatworks.com/

Really easy to use so you don't mind adding a bit every now and then.

[Rum Runner]

Jackleman said:

Y10 is not slow if you use it in the right temperature conditions, normally restores the gel back white in a couple of minutes.

Well you can just spray on the other liquids, not gel products like Y10 and hose off, know elbow grease required / brushes sponges etc.. I used to run boats for a living and on the crewed management team for Moorings with over 200 boats alone in the BVI...trust me Y10 is slow. Try doing a 70ft flybridge motor yacht in the heat with Y10..its not reaction time its the application time and getting it off after.

Every boat I know and all the private crewed yacht at least carry 1 gal of Osphro in a locker.
We also used it for de scaling engine coolant systems, Air Con units basically any thing that gets calcified growth.
For instance putting it in your raw water strainer and starting the engine for 5 sec and switching off, then starting after 5 mins would keep the heat exchanger and everything like new if done regularly. Given the water temp of 30-32C things grow fast. AC units become blocked quickly and soon loose valuable cooling.

I first met this product (which basically phosphoric acid) many years ago when cleaning the stainless on old boat which was very poor and rusty, after a few days of Duraglit polishing a Rastaman said try this as he walked down the dock. Within in 5 mins I had done the same as the previous 2 days.
Though if you want it last you need to go over with protective polish once washed off / dry and that goes for GRP and Stainless, but it really revolutionized the whole looking after boats in many areas.
Word of warning do not leave for long periods on Anodized Alloy as it can leave slight marks on spars etc.

Bathroom Cream cleaner for grip deck

Edited by Rum Runner on Monday 4th April 19:53