Red spots on non-skid

[brianc]

Last time I cleaned the non-skid on my boat, I ran in to some, maybe a dozen or so, of these red spots that will not come off. They're irregularly shaped, most are two or three millimeters in diameter. I've tried Starbrite non-skid cleaner, Softscrub, Bon-ami, Comet, etc. The only progress I made at all was with the Bon-ami and a toothbrush scrubbing for about 5 minutes to reduce the size of the dot by half. They do, however, come off the non-non-skid areas with a knife or something that can scrape or chip them off.

Any ideas what they are? Or even better, how to get them off?

Thanks,Brian

[shorebird]

Anyone doing any painting in your vicinity? Maybe on a windy day?

[brianc]

No painting that I know of but I was gone for a couple weeks so it's possible. They're not as uniform in color as I would think paint would be.

I also checked out some of the neighbors boats and didn't see any spots (doesn't mean they weren't there I just didn't want to go climbing around without permission!)

If you click a few extra times on the image you can finally get to the full size version...helps a bit to see.

[bill cartwright]

I have had these before. in Redondo Beach California and Ventura Marina as well. What it was rust from the power plants, close by, blowing there stacks clean at night and thus getting on the boats thru the wind as the carrier. The fog would come in and they would be solid rust the next day. It flows into the gelcoat and I used I believe phosphoric acid and it removed the red an turned black. I used a brass scrub brush or knife to flick oof the residue and hit it with a buffer with polishing compound and it was gone. Is there a power plant close by or large industrial complex? That is what I had. After wards, P G & E cleaned every one elses boat and cars free. Good luck!

[a64pilot]

Not exactly the same thing, but real close. Or said another way I've seen it.
http://www.carwash.com/articles/rail...-its-removal-2

[ShaktisBoy]

We are 1 mile south of the palm beach power plant. When the winds are from the north we get dirty decks. And the exact spots you are seeing. I clean the decks every few days to keep it off.

[JiffyLube]

I get spots in our gel coat non skid every once in a while, some the color of yours and some dark...could be mold. I use a pressure washer periodically (works great), and then apply some Woody Wax on the cleaned areas.

[brianc]

@JiffyLube - I don't think it's mold because every mold I've dealt with can at least visually removed with bleach...and I've tried that on this with no effect at all.

@bill cartwright, a64pilot, and ShaktisBoy - We are at probably a mile or so north as the crow flies from the Seattle industrial area as well as near to the Burlington Northern Yard. I believe there was a pretty stiff south wind when these showed up which would be consistent with something coming from the industrial area. I also noticed that for being gone a week or so, the decks were filthy...also consistent with your theories.

I'll have to pick up a wire brush, that seems like it would help flake it off better than the toothbrush I was using (worthless). What a pain in the ass. I'll have to ask around to see if anyone else in the marina noticed anything similar. I applied Woody Wax about a week earlier but obviously it didn't work for this (but the rest of the boat seemed to come clean more easily!)

Thanks for the input - much appreciated!

[Catalysis]

You might want to to give "Bar Keepers Friend" a shot. has worked well for me.
Paul

[delmarrey]

It's rust spots. Very common around old chain rode. Nitric acid is my choice. But any rust remover should work, just slower.

Note: Never grind any metal (even SS) aboard a boat that's not fixed to the boat. Grinding wheels contain iron grit.

PS: don't use a wire brush on gelcoat. It'll turn gray.

[Phoenician]

You can try Oxalic acid to clean off, or simply lemon juice.

[JiffyLube]

I think I would start with a dental pick, and see if you can pick the spots out.

[brianc]

@JiffyLube - dental pick - didn't think of that, good idea, that's about the right size for the job!

@Phoenician - any special precautions with oxalic acid? Mainly to avoid damaging the gelcoat...

Brian

[delmarrey]

Acids don't hurt gelcoat but dry solvents will, like acetone or MEK if allowed to soak.

[Capt RonB]

If its rust spots oxalic acid is quick and easy as mentioned before Bar Keepers Friend is oxalic acid in dry form. It can be applied as a paste by mixing a batch with water. Rust stain removers may contain oxalic acid, read the label. I use the cheap stuff sold at Lowes by the gallon and put it in a spray bottle. Liquid, paste or dry works great to shine up stainless.

Oxalic acid won't touch fiberglass or gel coat but it will stain or discolor stainless steel if allowed to stay on too long. Rinse thoroughly with water. The discoloration I've seen was from soaking a rusted up Leatherman tool in the stuff overnight. It may be an issue of the grade of ss in the tool as much as the acid.