Best product for stains on GRP?

[NFCN]

I have a 27 year old Moody 33 which has topsides which have been painted white over the GRP a while back. I have 2 types of stain to get rid of - a yellowy / brown (presumably fungal) stain, more in evidence nearer the bow but running along the length of the yacht just above the waterline, and the smoky grey exhaust stains on the transom from the exhaust outlet.

I'd be grateful for advice as to which products people find work best. I'll be scrubbing by hand!

Nick

 

[Fergus]

try searching - there's plenty of advice! Most seem to prefer oxalic acid-based products

 

[StephenSails]

The product you want is called Y10, its a green gel that you brush on and leave for a couple of minutes and then wash off, it is temperature reactive so you will need to do test spot.

Cheers

Stephen

 

[DickB]

Theres a stuff called Gel Kleen which is a little less fierce than Y10 but is very good for bird pooh and the like!!! Looks like wallpaper paste (probably is too with Oxalic acid!!!)

 

[johnalison]

Y10 is fine but I use a German product from Yachticon called Antigilb which is more liquid and comes in a nice bottle. I've occasionally seen their products in this country and more often in the Netherlands. They both work like magic on yellow stains and are quite good at rust. You should follow as soon as possible with a polish to renew the protection.

 

[owen]

this is what you want for the yellow stains. will last you ages .http://www.agwoodcare.co.uk/list_products.php?category=Bleaches and Acids

the black stains on the transom should be washed off with detergent do not be tempted to use abrasive as you will scratch the surface .

 

[Spyro]

Oxalic acid is great on GRP but not sure I would be using it on a painted hull unless I tried a very small patch first.

 

[Talbot]

or even

oxalic acid

BTW if you mix it with wallppaper paste, it willl stick on the GRP and do a better job. washing will then remove it, rather than it just sliding off.

 

[Dazedkipper]

W5 Limescale remover from Lidl, about £1 a bottle, works brill!

 

[PeterGibbs]

Brasso - really a form of jeweller's polish, is pretty good for most stains, low cost, and friendly to most surfaces.

Then there's Farecla paste - slightly larger particle size but pretty effectve on tougher stains. Buy it in a chandlery.

I endorse the advice to try each remedy carefully, apply no mechanical aids to clean, then apply a good coat of polish.

One warning - in spots where hand wear is heavy, the outer layer of the GRP will have thinned or even worn away. There is nothing I can suggest for this - certainly applying more cleaner will only worsen the outcome!


PWG

 

[samwise]

Y10 will do the yellow stain job brilliantly, but if you just apply it to the waterline it will show up the dirt on the rest of the hull and you have to be prepared to go over the whole thing with another cleaner. Y10 is too expensive to do the lot. I have to say I have tried most of the proprietory cleaners and pastes for post Y19 treatments and have had most success with a common or garden kitchen cream cleaner. Easy to apply, washes off and is massively cheaper that the proprietory stuff flogged in the chandlery. However, having used it it must be washed off scrupulously and a decent quality wax polish applied as soon as the hull has dried

 

[tangomoon]

The stuff (Wipe-Out) this replaces was very good - most just made a thinnish paste and wiped it on in October leaving the hull covered in a white dry film, then thorughly washed(and wiped) it off in April. Polish and go to sea BOL