Severe... lime? Scale? Something??? on cockpit floor

[hectoretc]

Greetings all,
I uploaded this photo to clarify a comment I was making on my centerboard downhaul line post and it reminded me (yet again) of another question I've been burning to ask.



Please note the very delicate hues of brown and white in the forward cockpit port side floor (deck?). As best as I can tell, this poor sad DSII spent somewhere between a couple weeks and a couple years nose down in some serious sludge deep enough that at least a couple inches of (lake/river/swamp) water had collected in the cockpit. The brown scrubbed off with some elbow grease and I had all but concluded that the white was simply fading until while cleaning some other scum off the CB housing with some abrasive cleanser, I after the fact realized I'd somehow cleaned a portion of the white off the deck showing the blue gelcoat. This told me that this was a coating of some kind rather than damaged gelcoat, but other than taking softscrub and a very stiff brush I've been largely unsuccessful in cleaning much of it off at all. I don't want to scrub so hard with an abrasive that I wear off the traction texture in the gelcoat, but I've tried LRC, industrial versions of LRC (Lime Rust Calcium remover), wink, and every other thing I can find in our cabinets and the local hardware shelf. This is a really nasty layer of something.

Any final ideas before I give it up and try to paint over it? I have no reason to believe paint will even stick to it either.

Thanks,

[Bob Damon]

I have had luck with a product called Iron Out. It is a powder and can either be mixed in solution or sprinkled on a wet surface and let set for a few minutes before scrubbing with a medium bristle brush. It works great on that brown lake scum that sets into the hull when a boat is in the water to long. I bought it at Lowe's. good luck.

[hectoretc]

Thanks Bob, that's one name brand I've not tried so I'll give it a shot.

Speaking of lake Scum, I don't know how I came across it, but I have found the most amazing product for cleaning lake scum and discoloration off of fiberglass.
MaryKate On & Off Hull & Bottom cleaner. Again, I'm not sure where I heard about it but this stuff is amazing! I searched this forum and can't find any references to it, but I do see references to MaryKate waxes etc.

My DSII hasn't been in the water yet, but I have a fiberglass Glastron ski boat that spent 45 days tied to the dock before I got a lift installed and it was just terrible how discolored and stained the boat was just in that short time from the waterline down. (Very weedy area of the lake) I tried powerwashing, scrubbing and all kinds of cleaners, but this On & Off is great.

It's kind of a thin milky liquid that I poured into a plastic roller pan, and used a paint roller to, well, roll it onto the boat bottom and then spray it off with a hose. It comes completely clean and looks brand new. No scrubbing per se, but as I said I used a roller so the normal back & forth action does a little natural scrubbing, but this is truely amazing stuff. I think I paid... $12 for 1/2 gallon on ebay?
So that's the good news!

The bad news is this stuff is major league toxic. We're talking serious rubber gloves and eye protection, and just don't plan on breathing when you're near it. I was working in the drive with a decent crosswind so as long as I was upwind all was well, but you don't want to even whiff a little bit of this stuff. The whiff I got (which is how I learned not to breath near it) smelled a very very sharp tangy smell but it burns your nose, throat and lungs almost immediately. Don't smell it to find out. There's 3-4 different acids in it that do the job but it cannot be used on metal so you also need to put a plastic sheet or blue tarp on your trailer and be sure to hose it down afterwards.
The EPA would likely prefer that you capture the run-off and dispose of it in a hazardous waste facility. Definitely keep it out of the lake.

I didn't mean to do a commercial here, but water line scum has been the bane in my boating for a long time and this is the answer I've been looking for. Wanted to share the info for others who also hate water line scum.

Hmmm... I wonder what this stuff would do with my little lime/scaling problem on my cockpit deck... I'll let you know...

[jdoorly]

Corrosive to skin & eyes, may cause resperatory tract burns, vapor harmfull.
That sounds like my old friend oxalic acid. I use it to dewax before adding a graphite finish or painting. Great stuff. Of course you don't have to scrub, you can't, it makes bristles evaporate! Don't fail to rinse it off quick or you'll be watching your gel coat blow off in the wind for years.