Waterline stain removal

[Sweet Chariot]

Hello all,

Recently slipped "Sweet Chariot" for a new coat of antifoul and had great difficulty removing the above stain. Despite an acid wash and intense "elbow grease" we were unable to remove the real difficult stuff and due to time constraints had to resign to leaving some of it there. Attached photos show the area concerned and I am curious as to how others get this stuff off. Any help is appreciated.

Steve



Before removal



the remaining stain

[Sweet Chariot]

The repeat photo was an error

[minaret]

Tape off your bottom paint and use a buffer to polish it out. If that doesn't work either occasionally I wet sand and buff, but only in extreme cases and only if it's gelcoat not paint.

[colemj]

We get that type of growth and have always been able to remove it with "On and Off" or some acid-based product with a similar name. The stuff smokes when you apply it, but the stains just go away. It even eats off crusted growth, although that sometimes takes a couple applications.

Mark

[HopCar]

I second On and Off, very effective for this application.

[zeehag]

the algae and oil mix that comes onto the boat just above the boot stripe also comes off nicely with a spray of clorox with the scrubbing with a 3m pad. is only use on boat i have found for clorox.

[witzgall]

It might not work in this particular case, but we have had very good luck using Concentrated lemon juice on our waterline. Just put it into a spray bottle undiluted, and spray on, then wait. Automagically, it will remove icky brown water stains from river water, etc....

Chris

[Beersmith]

Originally Posted by colemj

We get that type of growth and have always been able to remove it with "On and Off" or some acid-based product with a similar name. The stuff smokes when you apply it, but the stains just go away. It even eats off crusted growth, although that sometimes takes a couple applications.

Mark

+1
On and Off is quite effective

[CarlF]

Different cleaners attack different materials. I start mild and go stronger:

First - "Something to do it". Recommended by Active Captain. Great for simple exhaust stains and the like. Non toxic, smells good. No gloves.

https://somethingtodoit.com/

2nd - On and Off

Great for marine growth but not so good on petroleum based. Need gloves and glasses.

3rd - Acetone

Great for petroleum based. Need gloves and glasses. Limit time near fumes.


Carl

[Sweet Chariot]

Thanks for all the replies. Will let you know how it goes.
Steve
www.sweetchariot.blog.com

[chef2sail]

Have also tried FSR with good results for gel coat stains.

Dave

[JusDreaming]

in the islands they use "tidy-bowl" it woks really well. You will actually find it in the boat cleaning area in the chanderly

[LeaseOnLife]

I looked at a few MSDSs for the main ingredients

Tidy Bowl: 9% HCl (muriatic acid)
FSR: 4.5% oxalic acid plus 4.5% isopropanol alcohol
Marykate "On and Off": 20-25% HCl, 5-10% Phosphoric acid, plus some oxalic acid (<==Seems harsh to me)

Personally I use "Barkeepers Friend": 5-10% oxalic acid, plus abrasives.

Dirk

[Tingum]

My vote is for Sno-Bowl toilet cleaner, works great on tanic acid stains.

[LeaseOnLife]

Originally Posted by Tingum

My vote is for Sno-Bowl toilet cleaner, works great on tanic acid stains.

just by muriatic acid, from the sno-bowl MSDS:

Sno-Bol Toilet Bowl cleaner: HCl 10-20%, rest is water