cleaning

[sthurley]

The white gelcoat on the decks and coach roof has a dark speckle to it almost as though it has been hit with a fine paint mist from the yard it was sitting in where I bought it. The reason I think it is paint mist is because there are areas in the cockpit where the discolouration stops as though something was protecting it. I have used cif and a deck scrub but this does not appear to remove the speckle only dirt. Power washer again only clears dirt. Has anyone experience of an abrasive gel coat cleaner that may help, or some form of a paint thinners which would not damage the gelcoat?

 

[nigelmercier]

It may be rust, from bits of iron dust. Try Oxalic Acid.

 

[VicS]

The white gelcoat on the decks and coach roof has a dark speckle to it almost as though it has been hit with a fine paint mist from the yard it was sitting in where I bought it.

It's a possibility, as are the rust stains that Nigel suggests if anyone has been using an angle grinder nearby. Rust stains should be easy to recognise by a rust coloured stain surrounding each dark speck.

Treat rust stains, as Nigel says, with nearly saturated oxalic acid solution but they will continue to reappear until the little iron or steel speck imbedded in the surface has gone.

If you suspect paint try a GRP friendly paint stripper, ie one that does not contain methylene dichloride, or caustic soda solution.
Any paint stripper you can buy retail now will be OK .

Take care with oxalic acid and especially with caustic soda . Gloves and goggles minimum!

 

[macd]

+1
If it is rust from iron dust, the effect is miraculous. If not, no harm done.

 

[sthurley]

I don't think it is rust spots as there is no outer ring around each dot. The dots are as though a very fine paint mist has settled over the whole top. It does not look bad, it just does not seem correct, I can't imagine that it came out of the mould looking like that.

 

[ganter]

I'd be looking at the boats either side of you to see if someone has been doing a bit of spray painting.
All the same...don't go in too hard...try hot water and soap on a reasonably hard cloth first - should be enough to remove overspray.
If that doesn't shift it then go to a gentle paint stripper mixed with a little hot water, then Oxalic.

In the mean time, if it someone near by who's been spraying, nab them for the cost of materials!

 

[nigelmercier]

I don't think it is rust spots as there is no outer ring around each dot...

The ones on my boat looked like tiny freckles. If it's paint, then Jif will remove it, although Sif isn't nearly as good