Timber tannin stain on fibreglass deck

[SailTaz]

My boat hook leached tannin onto my fibreglass deck and has stained it. CLR has removed some of the stain but it is still noticeable. Any ideas on how to remove the stain safely?

[neilpride]

On & Off , wear gloves, use it carefully, only on gelcoat decks, do not let it touch plastics, windows, paint finishes etc.,,,, rinse with plenty of water when the stains disappear.

[Chotu]

Also, muriatic acid will take it right off.

Protect your lungs and skin

[Mickeyrouse]

FSR has worked well for me, though it may require more than one apply-and-sit cycle.

[capt jgw]

Originally Posted by Chotu

Also, muriatic acid will take it right off.

Protect your lungs and skin

That's what's in On&Off, with a couple other acids. Straight muriatic from the hardware store is cheaper.

[Chotu]

Originally Posted by capt jgw

That's what's in On&Off, with a couple other acids. Straight muriatic from the hardware store is cheaper.

I know. Just trying to make it easier on the OP.

better to have the muriatic acid suggestion so they can find it more easily than looking for a specific marine product.

it’s commonly used on the east coast of the USA when people do the ICW. There is a brown stain you get from the tannin in the water that is referred to as the brown smile or moustache.

And to make it even more generic, it’s just hydrochloric acid. Just have to be a pretty strong batch in order to get the stain off

[wholybee]

FSR, which is an acid (I forget which one).
It is better than cheap hardware store acids because it is a gel, and will stick to vertical surfaces instead of running off. Wipe it on, let it dry, then hose off.

You will need to polish and wax afterwards.

[Be Free]

You want to use an oxidizer on an organic stain. Sodium hypochlorite (the active ingredient in laundry bleach) works great and is not as dangerous as some of the others listed above. Tannin stains are very common where I am and I've never found one that a little bleach would not remove. Let it sit on the stain and do its magic.

[roberttigar]

If its con the hard-toilet bowl cleaner. Wear rubber gloves and be careful. Wife on with a sponge and immediately rinse with a lot of water.

If you are in the water-lemon juice. Put it a spray bottle and spray the yellow areas thoroughly. Wait 15 minutes and hose off. You may have to do it 2 or 3 times but it works and its a cheap solution-both are.

Bob

[AKA-None]

Originally Posted by roberttigar

If its con the hard-toilet bowl cleaner. Wear rubber gloves and be careful. Wife on with a sponge and immediately rinse with a lot of water.



If you are in the water-lemon juice. Put it a spray bottle and spray the yellow areas thoroughly. Wait 15 minutes and hose off. You may have to do it 2 or 3 times but it works and its a cheap solution-both are.



Bob

Sarcasm on
Pretty sure my wife would object to that

Sarcasm off

[JPA Cate]

After the stain disappears, neutralize the acid, by wiping the area with baking soda solution (1 tablespoon to 1/4c. water). When it quits bubbling, the acid is no longer active. Then rinse with fresh water.

Ann

[team karst]

Originally Posted by Be Free

You want to use an oxidizer on an organic stain. Sodium hypochlorite (the active ingredient in laundry bleach) works great and is not as dangerous as some of the others listed above. Tannin stains are very common where I am and I've never found one that a little bleach would not remove. Let it sit on the stain and do its magic.

I took this advise yesterday on some teak oil drippings; Bleach worked great, and I had tried acetone before with slow/limited results.