T&T: Oxalic acid and bottom paints

[Richard Quarles]

> From: "dbruckel@earthlink.net" <dbruckel@earthlink.net>
> Subject: T&T: Oxalic acid and bottom paints
> To: "trawlers-and-trawlering"
> 	<trawlers-and-trawlering@lists.samurai.com>
> Message-ID: <410-220069630149491@earthlink.net>
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>
> Sno-Bowl, Wood deck bleach or other oxalic acid containing acid  
> solution
> will erode away ablative bottom paints, at least the ones I've  
> used. I've
> not found this to be true with modified epoxy bottom paints or boot  
> stripe
> paints.

In the ablative paints, the Cu2O is pretty easily dissolved away.

>
> Since my boat is hauled annually for winter storage, I've been more  
> or less
> forced to use ablative bottom paints. To reduce the damage from  
> oxalic acid
> treatments near the waterline I made a small square sponge  
> applicator which
> is screwed to a 18 or so inch long dowel stick. Using swim  
> flippers, and a
> cheap life jacket, I pour some oxalic acid on the sponge to dampen it,

Interesting!  Oxalic acid is a solid.  Do you dissolve it in water  
firswt?

> then
> run it along the waterline, just above the bottom paint, rather like
> putting paint on with a roller. One trip around the boat takes  
> perhaps 5
> minutes at the most, then it's rinsed off with a hose and wash down  
> pump.
>
> It is my understanding that the ICW mustache is from iron content  
> in the
> water and the acid oxidizes it away.

Actually, it doesn't oxidize the iron.  It's already in the 3+  
oxidation state.  It forms a complex ion with the iron whichis  
soluble under the conditions which prevail in the oxalic acid solution.

> An application of two coats of wax on
> the V of the bow will greatly reduce the severity of the mustache.
>
> Dennis
>
> Dennis Bruckel, Cruising Editor
> Waterway Guide
> Albin 27 Sadie B
> 407 414 0531
> website debruckel.com
>

Rick Quarles
Barric II, Nordic Tug 32-147
New Bern, NC