How To Remove Brown Water Stains?

[sigbear]

Hi,

I bought a new/demo 2009 Catalina 309 this summer and after 3 weeks on the Kentucky "lake water" the boat had brown water stains just above the water line, lower stern and swim platform. I tried washing the stains with a boat wash soap and brush and also marine nine.
I really scrubbed and scrubbed with no success. There is a lot of clay in this water which I believe is the culprit.

Suggestions will be appreciated.

Donny

 

[RichH]

Tannins !!!!!!
Oxalic Acid is your friend. Get it (in crystaline form) from a paint store or harware store. Also called 'wood bleach' but look at the lable to be SURE its oxalic. Oxalic is usually not available in eco-whacko states (but they do still sell rhubarb, go figure).
To use: mix crystals into HOT water (1/2 gallon) until no more crystals 'dissolve'. Then simply apply with a soft long handled deck brush, etc. Should INSTANTLY remove tannin and iron, etc. staining from gelcoat, sails, etc. All surface should then be rinsed very well after staining is 'bleached out'.

Caution: follow package safety directions as oxalic can rapidly absorb through your skin and form very sharp and painful 'oxalate' crystal in your kidneys, etc. Wear gloves and eye protection

 

[Capn Dave]

Snow Bowl

People will tell you all sort of things Mary Kate On Off hull cleaner, Oxalic acid, They all work, by the way.
If you want bang for the buck...... Snow Bowl toliet bowl cleaner. $1.79 a bottle.

Can't beat it

Dave

 

[Joe]

For the biological type stains, like algae, I've had success with common acid based toilet bowl cleaner, available cheaply at any restaurant supply house like Smart & Final. My method was squirting a small amount of cleaner direclty on the wetted brush of a long handled pot scrubber, then quickly slushing it over the brown stuff... getting immediate results. Then dipping the brush in clean water to finish cleaning... then hosing off with a fresh water rinse. There was absolutely NO scrubbing necessary.

I will say that this was usually done in the cleaning area where I stored my trailerable boat. Be careful if your marina has issues... but be aware that you will only be using a couple of capfulls of the cleaner for the whole boat.

 

[locomo14]

Brown Stains

Try Lemon Juice Takes time before stains fade....... but it works.

 

[rardiH36]

Here's another way of sourcing oxalic acid. This from a post a week or two ago. Note the picture at the end.

Cleaning with Oxalic Acid: The $1 "The Works" (The Version With the Green Cap)Works
Top

A lot would depend on what type of stains and deterioration you've got. Read Maine Sail's "Tips for a great buff wax" which is posted always on top of the "Ask All Sailors" postings as a sticky. That's sure to get you a good result for the topsides (hull).

Some have mentioned oxalic acid based cleaners. Oxalic acid works very well to remove rust stains, tannin stains and mineral deposits. More than one application is usually necessary. And don't let it remain on painted or metal surfaces. You may not notice immediately, but within just very short time it can dull the surface sheen.

About six months ago, I had great results removing the light brown tannin stains from near the water line on my hull with an oxalic acid based tub and shower cleaner product. See the attached picture of my test section before I proceded with the whole hull. I also noticed that it restored a bit of shine to the gelcoat. It occured to me that over the years, perhaps my whole hull (topsides) might have developed hard mineral deposits. So I applied the product all over with just staturated paper towels. Without any other work, the topsides looked cleaner and whiter than prior efforts with even wet/dry sandpaper and polishing compound. I did a bit of the newly cleaned hull with polishing compound and wax. Then I did a bit with wax only. The wax only section wasn't much different than the polishing compound section, so I just finished the whole thing with wax.

Best yet, the product I used is available at the DollarTree store for yes, $1.00. Primary active ingredient is oxalic acid. One bottle was enough for my hull. But buy two. You can afford it! Here's a link to the product. http://www.dollartree.com/cleaning-s...6065/index.pro

This product works great removing rust and tannin stains from sails as well. Just dab some on the rust stain with a small paint brush. After a few minutes you should notice the rust looking lighter. Repeat until gone. Then rinse off with fresh water. Best to apply on a cool day so the product stays wet longer. My sails are Dacron synthetic. Where I did apply the product, I haven't observed any damage or accelerated deterioration. But get a second opinion.

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[zeehag]

try vinegar--i cheap and is acetic acid. less toxic than oxalic and less of an overkill thing. have fun. vinegar is cheap and easy to find everywhere.
for rust-- barkeepers friend. perfect.

 

[Maine Sail]

Oxalic is cheap and works well but I use a gel to try and keep the acid off the anti-fouling bottom paint. Acids will eat the copper right out of the bottom paint if not used carefully. This could potentially make the one or two inches above the waterline basically useless at repelling growth if you cleaned your boat in-water then loaded it for cruising. If you do it out of the water without a drip skirt you could ruin a LOT more of the paint.

The hull of my boat is always waxed and I really don't get to much if any staining. A good coat of wax can go a long way to minimizing these brown stains. I did however leave my inflatable in the water for a few weeks and got enough staining to illustrate the process.

This is easy and is safe for gelcoated hulls. While I have used acids on LPU paints I don't suggest it unless you are really, really, really careful.

To clean waterline stains I use MaryKate On & Off Gel. This is a HUGE improvement over the regular non-gel On & Off or basic Oxalic. It's also a lot cheaper and stronger than Davis FSR stain remover but works similarly. There are a lot of products out there that contain acid and will work but the On & Off Gel is one of my favorites. It also has much less "acid" odor than the regular On & Off. This is a great step to do before waxing a boat and it will whiten up most any old tannin/rust stained gelcoated hull.

Always wear rubber gloves, this stuff is acid, and use cheap chip brushes to apply. This whole process on my inflatable takes less than 10 minutes and requires NO rubbing. Simply apply with the chip brush and watch it eat away the stains. Regular oxaic acid, or oxalic acid crystals mixed with hot water will work too, and is slightly cheaper, but it is thinner and can drip and run and can eat the copper out of bottom paint. The gel stays put for the most part with considerably less dripping.

Before:

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All Finished:

 

[rgranger]

I painted my hull tan...:dance:

 

[Dan Johnson]

Davis' FSR...

is the common, easy to use gel that many of us use at my marina to remove the tan "mustasche" and waterline mark from the tannin that RichH noted. Paint it on with a disposable brush, let it sit for a few minutes then wash/wipe it off with a wet sponge and the stain disappears. Used sparingly, a container will last for a few seasons.

 

[inarathree]

Barkeepers Friend (Oxalic Acid)