"SASIINC" wrote
I just bought oxalic powder at my local hardware store. To
clean the bottom of my boat, what proportions due I mix it.

You probably ought to start out with what it says on the package to use for
normal wood cleaning. The kind I buy comes in a little tub that holds about
a pint or so. I mix about half the container with about a gallon and a half
of water in a garden sprayer. It's pretty forgiving, so I just mix by trial
and error. If I mix it a little too weak, it doesn't remove stains very
well. (I spray a spot and if it doesn't start looking clean within a minute
or so, I declare the mix too weak.) If I mix it a little too strong, it
doesn't do any harm, but it doesn't do any better job than an optimum mix,
so I try to work up from a weak mix so I'm not wasting the stuff. Once I
decide the mix is close enough I squirt it on the hull, let it do its stuff
for 5-10 minutes, then rinse thoroughly with the garden hose. Then I use
soap and water to scrub off the stuff that OA can't cut, and if there's
still stains left I repeat the OA treatment. Oh, and I don't wear any
protective gear, (sorry Harry) but I'm not claiming that's a smart thing to
do.