Oxidation, I think; worse on gray hulls?

[Dr. D]

My boat is now on the hard. This past Thursday and Friday I cleaned the topsides and hull, then waxed the hull. Some day next week back over and wax the topsides. On the hull, on the port side, there is a patch about 2' by 2' with an odd speckling. I believe it is simply oxidation, but it is odd being only in one place. Would you consider this mild or moderate oxidation? Should I use a strong compound on it, or go easier? Or is this something else?

There is a boat on stands next to mine and maybe one or two years older, but also gray hull. I don't think that hull has ever been thoroughly cleaned, nor waxed. The hull has all sorts of discoloration, speckles, etc. Are these issues worse on gray hulls?

 

[Ralph Johnstone]

All you can do is experiment. Start REEEEEEEEEEAAAAALLLLLY slowly in a very small, less inconspicuous area (if at all possible) and see how it reacts to mild cutting compound all the way to final polish. Keep it small and do by hand. Not easy and not cheap as you'll need a machine such as a Makita 9227C to do it right.

 

[Project_Mayhem]

I'm no expert but I agree if that's oxidation I would try a moderate cutting compound and see what happens. Worst case scenario you end up sanding it.

A friend and I sanded the whole hull of my 25 footer over the course of a weekend. We read through Mainesail's article and took some advice from a local fiberglass guy. We started at 400-600 grit and worked our way up. It was a lot less scary than we thought it would be and a lot easier. Within an hour we realized there wasn't much fear of sanding through the gelcoat. The project took about 25 hours. If you do it yourself the biggest expense will be the sander and buffer

 

[Don S/V ILLusion]

oxidation usually manifests itself by creating a chalky appearance - run your hand over it to see if any residue wipes off on your hand. If not, it is more likely delamination of the paint. The former can be removed most effectively by lightly sanding followed by polishing but only if sufficient paint thickness allows. If the latter, sand away as it all has to come off.

 

[Davidasailor26]

The gray doesn’t seem to hold up great in the sun. I wax each spring but after 6 seasons it was looking pretty splotchy this spring. I was going to do the whole compound thing, but then wanted to rush the boat into the water before COVID lockdowns. So we just waxed it lightly from the dinghy in the early summer. This is what it still looks like -

The color variation (other than the dirt streaks) aren’t reflections, they’re the splotchiness from variations in oxidation. I’m planning on compounding more this winter to clean it up some.

 

[Hunter216]

but it is odd being only in one place.

Could this be caused by a fender rubbing in that area?

 

[Project_Mayhem]

Perhaps a better picture would help determine what kind of damage this is

 

[SoSound]

I've been noticing a similar situation develop on our gray hull. This year, I cleaned it and waxed with a moderate to heavy oxidation wax, and it was not as noticeable. It looked good from a distance, but if you really looked at it, you could still tell that there was oxidation in several places. Next step will be a cutting cream and then wax again right away. The picture shows a reflection from the water.

 

[Dr. D]

Perhaps a better picture would help determine what kind of damage this is

Here is the other picture I have:

 

[SoSound]

That's it...
One problem that I'm having, is figuring out what is the best combination of equipment and material to use. I have a Makita polisher, but the pads recommended or sold by the finishing material manufacturers don't necessarily fit my equipment. If a manufacturer recommends and sells a foam cutting pad to use with their product (but it's the wrong size), will the pad recommended and sold by Makita work as well (if it's a different material)? Or will I end up with a streaky, scratched up, burned up mess, where I once had a great looking finish?

 

[Scott B]

Lots of good reading here. I typically polish, ( Presta Cutting Cream ) at least every 2 years. Wash and wax every year. I don't think it will matter much if it is grey or white, it will still show the oxidation if not kept up.

Tips For A Great Buff & Wax

Buff Polish & Wax Try these products (for Gel-Coat only not intended for Awlgrip) The Cliff Note Version: Steps: #1-Clean the hull with an acid base cleaner like FSR, oxalic acid or On & Off to remove rust & tannin staining. (only if necessary) #2-Wet Sand by hand 600 (if real bad)...

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