Stains in 30 year old gel coat

M

mini1

New member
What is the best product/method to remove stains/mold in 30 year old gel coat that has been exposed to the hot FL sun for at least 15 years? I generally work on late model boats and have not encountered this before. The old gel seems to be very pours and there are random stains/mold all over the sides of the cabin. Regular or heavy duty compound will not touch these stains. There is painted (old-skool) non-skid and freshly restored woodwork around the work area. I cannot spray a stripper on, because it will eat the non-skid paint.



Any ideas?
 
I work on a lot of older boats that require wet sanding before compounding (800 grit - 1500 grit - 2500 grit). Sometimes it works on staining, other times it doesn't touch it.
 
How can you tell it has thin gel coat? I'm not questioning your judgement, I just have never seen a boat with noticeably thin gel coat...what are the signs of thin gel?
 
It is very thirsty. It absorbs anything I put onto it like a sponge soaking up water. That leads me to think the gel is very thin, just as a car would do if the clear was shot.
 
mini1 said:
It is very thirsty. It absorbs anything I put onto it like a sponge soaking up water. That leads me to think the gel is very thin, just as a car would do if the clear was shot.
Click to expand...



Gel coats are porous by nature, a gel coat that is old will "drink" no matter what, but that is not a sign of thin gel coats. If the gel coat is oxidizing then the only way to fix it is to sand, glaze with Megs 3 several times, seal with a hybrid wax. My guess is the Polystyrene is breaking down too fast to stop, so repeated glazing's will help, but its likely a loosing endeavor.



Gel coats are very different than clear coats systems.



Cheers,

GREG
 
Mini, as you said, it's a 30yr old gel coat.

Looks like it's the gel-coat starting to fail. Or maybe this gel coat has been repaired before.



So, before going into abrasive methods, perhaps you can try these first:



1. Wipe the problem areas with acetone.

2. Soak it with full-strength All Purpose Cleaner overnite.

You can also try Coke (yes, Coca Cola!) or vinegar. These have produced quite good results.
 
Not many responses here. I subscribe to some boating forums as well and will offer up advice I have seen on them.



You might try Soft Scrub (if the stain is on the surface) or Sno Bowl toilet bowl cleaner (if you believe the stain has soaked into the gelcoat).



I've read that Sno Bowl will damage chrome if left in contact too long. Some of the old timers swear by it to remove fish blood stains though. I suspect it has bleach in it.



As always, YMMV. I would definitely try a test spot using an old toothbrush (or similar) before soaking down the entire stain.



Best of luck, TerryD
 
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