Removing stains from gelcoat hull

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Miker

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I can't shift some stains caused, I suspect, by rainwater seeping over the winter through the teak gunwales which had been coated with Deks no1, plus in parts where I was a bit slaphappy last spring with the Deks. If it is not that, I've no idea where the stains came from. I've tried 3M Fibreglass Restorer and Wax which shifted some. I also tried Starbright Liquid Rubbing Compound which was of no use at all.

Can anyone recommend something more powerful, please?
 
If it is dried Deks Olje, I am not sure that Oxalic acid is the cure, it is more appropriate to water based discolouration, I am just not sure it is the miracle solution in this case. I would be more confident about using a more abrasive rubbing paste like Farecla. The 3M stuff is a very soft polish and with enough elbow grease will eventually remove anything but Farecla or similar will be much faster, finish with the 3M wax paste as the last stage. If you need to rub it wet with 600 then 1200 grit paper, the 3M paste will bring back the gloss.
 
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Try Chine Shine

Have a go with "Chine Shine" - Google it for supplier. About £20 for a large bottle - goes a long way - non-toxic - brush on and wash off. PBO did a test on it last year and I bought some on the strength of it.
 
dmmbruce said:
Oxalic acid.

Mike
Click to expand...

This man speaketh the truth.

Acquire some oxalic crystals (ebay is cheap). Obviously if you buy the crystals you have to dilute them in some water to form a solution and then apply it to your stains and it'll get rid of most in about 10-20 mins. Try not to let it dry. Wash it off afterwards when you're finished.
It's the active ingredient in the expensive pots of Y10 but you get to mix it as strong as you like for less than half the price of some Y10.
 
Id start by trying what ever domestic cleaners you can find at a home.

If abrasives like Farecla will do it so might Cif.

If an acid like oxalic will do it so might Cillit Bang Grime and Lime

Take care with oxalic acid. Its toxic and can be absorbed through the skin so wear gloves.

Take care with Dilunet it contains caustic soda. Keep off skin, out of your eyes at all costs and off paint and varnish.
 
Y10 is excellent. I've used it on very bad rust stains on white gelcoat and deck paint. It is a gel so stays put while it works.
I guess you can use oxalic acid crystals mixed in with some soft soap but I'm unsure of how to mix certain strengths.
 
Forest Girl said:
Y10 is excellent. I've used it on very bad rust stains on white gelcoat and deck paint. It is a gel so stays put while it works.
I guess you can use oxalic acid crystals mixed in with some soft soap but I'm unsure of how to mix certain strengths.
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I just put some tepid water in a washing up bowl (typically a litre) and then add 100g of crystals. Stir till dissolved.

What does the soft soap do?
 
Another vote for Dilunet. I had some dried on varnish/teak oil stains on my cabin sides when I bought my boat. They looked very ancient and soaked in and I thought I might have to live with it, but Dilunet got rid of them completely.
 
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