Stained Gel Coat, how to clean?

[Mightychan]

My boat has a hydraulic swim platform. This past weekend, we had the platform lowered into the water most of the day. The water was darker than normal, stained with tannins flowing down the rivers to the Gulf. The tannins stained the gel coat on the platform "tooth rot yellow". It doesn't show up all that well in the attached photo, but you can see the difference in color from the stationary platform (where my feet are) and the hydraulic platform. It's very obvious in person. I have cleaned it twice with West Marines concentrated non-skid cleaner, and once with bleach, but it's still yellow. What can I use to get it back to white? Thanks, all.

 

[rmlsll]

 

[BillK2632]

+1 - On/Off is VERY strong, wear gloves and a mask you don't want to breath or get it on you. But it will definitely get the job done. Probably want to give it a coat of wax after.

 

[fwebster]

50% solution of muriatic acid and water in a spray bottle or pump up sprayer: Spray on watch the brown stain dissapear then hose off the platform. I have a white hull and this is a regular event for me every time we run over to Apalachicola on the ICW.

 

[paulswagelock]

50% solution of muriatic acid and water in a spray bottle or pump up sprayer: Spray on watch the brown stain dissapear then hose off the platform. I have a white hull and this is a regular event for me every time we run over to Apalachicola on the ICW.

^^ This
Lowes and Home Depot sell a "green" version - a little easier to work with. $6 and done.

 

[Little Ducky]

This stuff is fantastic for my rusty water stains.

Squirt on and watch them fade away in front of your eyes.

You can find it at home depot.

 

[CliffA]

'Bar Keepers Friend'.....its cheap and can be found almost anywhere.....it contains oxalic acid.....just wet down the platform and sprinkle on the BKF....work it around with a stiff bristle brush and let it do its magic for around 10 mins....then scrub lightly with the brush and rinse off....it will leave the gelcoat looking bright white....

cliff

 

[paulswagelock]

This stuff is fantastic for my rusty water stains.

Squirt on and watch them fade away in front of your eyes.

You can find it at home depot.

Oxalic acid - same as Barkeepers, and most toilet bowl cleaners. Good find.

 

[SillyKnot2]

This stuff is amazing, Fiberglass Stain Remover.

 

[Little Ducky]

View attachment 57345 This stuff is amazing, Fiberglass Stain Remover.

I never had good luck with this product and I really wanted it to work when I was dealing with stains.

 

[fwebster]

Bar Keepers Friend and FSR will eventually remove tanin stains from fiberglass........if you want to spend 1/2 a day on your hands and knees. It takes loger to mix up 1/2 gallon of dilute Muriatic acid than it does to remove all the stains on a 14ft swim platform. For smaller areas, try Whink Laundry Rust Remover in a squirt bottle. Rust-Aid is sold in Florida in gallons to remove sprinkkler stains from home foundations.

 

[OllieC]

I never had good luck with this product and I really wanted it to work when I was dealing with stains.

I agree. Neither have I & I have a few rust spots that need to be taken care of.

 

[ZZ13]

Starbrites Fiberglass stain remover removes it in seconds. I just spray some out of its spray bottle, and then spread it around with a brush so I don't waste too much. It's all gone in a few seconds.

 

[dwna1a]

Iron Out works well for me. Most hardware stores have it

 

[dpvandy01]

+ 1 on the Iron out. I'd personally be leery of Barkeepers,, it is a fairly abrasive product