Mary Kate On Off Cleaner

Searayguy185

Member
Jul 17, 2017
87
Wisconsin
Boat Info
2004 Sea Ray 185 Sport 4.3 V6,

2008 Toyota Highlander Sport
Engines
Mercruiser 4.3 V6, Alpha 1 Generation 2
I bought this product to clean the underside of my hull and was curious if it is safe to use while the boat is on a painted trailer. I guess i don't really have much of a choice since that would be the only way for my to clean the waterline that formed from leaving my boat in a few day here and there for vacations. Should I spray the trailer with a hose before and after I spray the boat with on off cleaner? Any suggestions would be great.
 
I would think it would be OK for a painted trailer.....but it will stain a galvanized or aluminum trailer.....suggest you test a small spot beforehand just to be sure.....it is powerful stuff with two different acids if I remember correctly......

cliff
 
Yeah, should be ok on paint, but keep it off anything bare metal or galvanized. It would not hurt to spray the trailer and outdrive with water first - water neutralizes the acid. I put it in a spray bottle and spray about 1/3 of the bottom at a time then rinse. It really get's the job done but is VERY strong, contains muriatic acid , eye, mouth and skin protection - no kidding! My boat was stained pretty bad at one point from the water in Lake Tillery, one treatment of On Off and it was like new again. I now use the less caustic Oxolic acid version.
 
Yeah, should be ok on paint, but keep it off anything bare metal or galvanized. It would not hurt to spray the trailer and outdrive with water first - water neutralizes the acid. I put it in a spray bottle and spray about 1/3 of the bottom at a time then rinse. It really get's the job done but is VERY strong, contains muriatic acid , eye, mouth and skin protection - no kidding! My boat was stained pretty bad at one point from the water in Lake Tillery, one treatment of On Off and it was like new again. I now use the less caustic Oxolic acid version.
Thank you for your reply, do you just spray it on or do you use old paint brush to work it as well? Thanks
 
I used it to clean my first boat every fall when I pulled it. It works well to get the brown algae and water staining off. But after two years the rust on the trailer was pretty significant. I was not as careful as I am suggesting below. The stuff got down into the grooves of the trailer metal (like where the fenders were bolted on) and that was where the rust started. It also got on the back of the brakes and rust started on the drums. Keep in mind I am in fresh water so this was not salt related corrosion.

Protect the trailer as best as you can. Consider using a tarp and keep it off the bunks/rollers. That stuff will eat the paint and will start corrosion. Nasty stuff. Stay away from the fumes when you use it. Use heavy duty rubber gloves too. Don't spray it. The mist overspray would be bad news. A sponge might work if you pressure washed the crud off first. It does damage most sponges though.

You may want to have some baking soda/water solution around to spray/neutralize it after.
 
So to clarify my boat isn't bad at all in terms of water stains. I am just wanting to get staining off from keeping it in the Wisconsin River for two nights on vacation. That being said is there a better product that isn't as harsh that would not damage The trailer? I used to use this product on a prior boat that I use to keep in the water for the whole season. Since this is not the case there may be a better product for me. Thank you
 
Wipe it on the boat with a rag or a sponge and let it sit for a couple of minutes. Then, wipe it off with some rags to get it as dry as you can. Use a good spray bottle to lightly spray a solution of baking soda and water to neutralize what remains and dry it off with some rags. Wash the boat with your regular soap. Only use the hose on the last step to get the soap off. By the time any of it gets to your trailer it will be neutralized and very diluted. Just take care not to drip and of it on your trailer along the way.
 
If you just want a general cleaner Spray-9 is fantastic on just about anything and for Spider and Bird crap .... Starbrite Spider and Bird Stain Remover is magic.
 
I would try an Oxolic Acid based cleaner, not nearly as strong as On Off, but does a good job for light staining. I spray it on, but you can wipe it on also. Spray on a calm day works fine on my small boat, I see others use a sponge or sponge mop. Let it sit 5min or so and rinse. I do it with the boat on a wooden wash rack so don't worry about a trailer.
 
I would try an Oxolic Acid based cleaner, not nearly as strong as On Off, but does a good job for light staining. I spray it on, but you can wipe it on also. Spray on a calm day works fine on my small boat, I see others use a sponge or sponge mop. Let it sit 5min or so and rinse. I do it with the boat on a wooden wash rack so don't worry about a trailer.
what product would you recommend?
 
you can also spray any parts of the trailer that you are concerned about with WD-40 prior to washing the boat....this should help keep the acid away from exposed metal parts.....I used to do this the few times I dunked a galvanized trailer into salt water and it worked well to prevent rusting....even spayed it on the wheel lug nuts.....

cliff
 
I would try an Oxolic Acid based cleaner, not nearly as strong as On Off, but does a good job for light staining. I spray it on, but you can wipe it on also. Spray on a calm day works fine on my small boat, I see others use a sponge or sponge mop. Let it sit 5min or so and rinse. I do it with the boat on a wooden wash rack so don't worry about a trailer.



actually it is 'oxalic acid' and Bill is correct that it is safer to use and will not stain a trailer......

I used 'RustAid' from Home Depot to clean the hull....it has 7% oxalic acid and does a good job and is cheap.....here is a link....works great on cleaning stainless steel also....

cliff

http://www.homedepot.com/p/RustAid-22-oz-Trigger-Indoor-Rust-Stain-Remover-ESX20005/206726457

0fe2c14e-b402-4e7c-b066-6a2c5625b208_1000.jpg
 
Whoa. On Off and Oxalic acid is fine when you are pulling the boat after a season on the water but why would you use it after just a few days in the water? Pull the boat, wash it down and use a good cleaner wax on the hull to clean any stains off this way you not only get it clean you benefit from a fresh coat of wax and no damage to your trailer.
 
Anyone have suggestions on what might be a good fit for me as to remove minor water lines? Can you use products to clean your bathroom? Or Could they damage the gelcoat
 
If you just want a general cleaner Spray-9 is fantastic on just about anything and for Spider and Bird crap .... Starbrite Spider and Bird Stain Remover is magic.

Methinks Little Ducky may have nailed it?

"Do The Least Harm First" seems to me to apply to anything involving gel coat (or exposed metal) ... which for me means a) really determining -precisely- what composes the stain I am trying to remove (is it biological like mold-slime or grass stain or, chemical like rust?, etc.); and, b) identifying -exactly- what chemicals or compounds make up the "solution" I am considering.

I can't count the times I have "won the battle but, lost the war," that is, removed a particularly tough stain, only to discover I had permanently (and quite unintentionally) altered (I.e., "etched") the surface I was trying to clean --- or another surface nearby, such as is the case with your trailer.

Here's a good article: http://www.bottompaintstore.com/blog/gelcoat/removing-stains-gelcoat/

There's this at West Marine:
AMAZING
Roll-Off Cleaner & Stain Remover


or this at ACE Hdwre:
Star Brite 32 Oz Instant Hull Cleaner (ACE hdwre # 81732)

Best o' Success (and please report back and let us know what worked on your hull (but "not" on the exposed trailer)!
 
You guys must have some mighty powerful birds (and their poop) to even consider using an acid product on your boat.

Our boat sits under a galvanized roof and get lots of birds (and their calling cards) but I only use water and boat soap to remove the droppings. I spray down the entire boat to let the water soak into the poop, then use a long handled, medium bristle brush and boat soap to go after the poop.

Works every time and I don't have to worry about using an acid product on the boat.
 
I bought this product to clean the underside of my hull and was curious if it is safe to use while the boat is on a painted trailer. I guess i don't really have much of a choice since that would be the only way for my to clean the waterline that formed from leaving my boat in a few day here and there for vacations. Should I spray the trailer with a hose before and after I spray the boat with on off cleaner? Any suggestions would be great.

From what I gather, the OP is targeting "water-lines," but definitely, bird droppings are nothing compared to a lot of water-lines (particularly if the hull isn't waxed regularly).

I'm following this thread with interest stemming from the fact our boat will be on a HydroHoist as soon as we're finished after each use; however; the OP's post reminds me I'm going to have to figure out to wax and maintain our hull, around the bunks, etc.

GFC, that vessel is exquisite!!!!!!!!!!!
 
If you just want a general cleaner Spray-9 is fantastic on just about anything and for Spider and Bird crap .... Starbrite Spider and Bird Stain Remover is magic.
Starbrite spider and bird cleaner is excellent. Even better is the Starbrite Spider repellant which works magic in keeping them away so the clean up is even easier.
 

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