On & Off Hull Cleaner

I have heard good things about this product - has any on this site have any experience with it and if so, what are your thoughts?

It goes on & off so easy, it is like it is not there!

On/off works awesome but be very careful with it- it'll eat anything with paint FAST, so rinse things off quickly (trailer, etc). Also be careful not to get it on you, especially if you're spraying it on the hull. It's a very strong acid, nasty stuff. Extremely effective though!

If you're used to the effectiveness of Lysol+hydrogen peroxide and then were to one day try On/Off, it would be analogous to waking up one morning and deciding to brush your teeth with gasoline. Totally new experience.

Where can one buy On & Off hull cleaner?

8122pbrainard wrote: Mark (LLS) has been doing some testing on the acid based hull cleaners and got the same results I've noticed. Yes, the stuff works great but then the staining comes back even quicker. The thought is the acid opens up the pores in the gel.

Come on now, Pete- I figured you'd give us a more scientific explanation than that! The acid etching seems plausible- how does it open up the pores?

It should go without saying that when using a caustic cleaner on your hull, that it *probably* wont leave any wax behind. Best to give it a fresh coat to keep the staining down (and easier to clean).

Maybe its a terminology thing... by "opening up the pores" youre really saying that the acid roughs the surface up slightly, right? Same effect as a very fine grit sand paper? That I buy. Im not aware of gelcoat having a "sealing layer" on it other than whatever wax you choose to apply though.

Totally agree Alan. Ive never gotten the impression it does anything harmful to the gel (paint is another story!).

Chemical resistance of polyester resin

LOL, good advice, Alan.

On and Off works very well, you definitely want to use gloves when using it too.

West Marine used to sell this stuff called "Roll Off". I haven't noticed it stocked recently though. It seemed to work almost as well as the On and Off, but a lot less harsh on the skin.

Oxalic acid is the worst, but all acids especially after repeated use will indeed open up the pores(not make bigger, just open back to original size when the gelcoat was applied/cured), some believe they will even make new ones similar to how etching works, but I've not seen firm proof on that when acid cleaners are used properly. I guess I need to go back and first explain that gelcoats have pores,granted its at the mircoscopic level, but that is how stains and algae get a foothold on the surface. Infact all hard surfaces have pores. Waxes help prevent this by sealing(filling in) these holes making the surface smooth at the molecular level. Since this is merely a filling and not a chemical bond it isn't permanent, which is one of the reasons you have to reapply wax every so often. Just do a google search for gelcoat porous or pores and there are a gazillion sites probably doing a better job at explaining it. The Hull Truth usually has a thread once a month on it. this site is also a decent explanation (see the cleaner section at the bottom).

Gelcoat Pores

Another on the meguiars site, see the meguiar's tech 1st post on gelcoats:

Gelcoats vs. Automotive

I'm by not means an expert so more than likely I'm not explaining it clearly. By "open up" i mean removing any foreign matter that filled in the pore to start with. Not making the pore physically bigger than it was originally.