Ditto on oxalic acid. Apply and it will instantly remove the rust
stain.
Also good for removing the 'brown moustache on the bow and waterline
(which is tannin and iron staining.

Wear rubber gloves when using oxalic as it quickly absorbs through your
skin and recrystalizes in the nephrons of your kidneys .... doing great
damage.

In article , RW Salnick
wrote:

wrote:
Ladies and Gents

I wonder if I could tap the combined wisdom of this group to help me
deal witht he results of my stupidity.

I have a nice rust stain in my gelcoat, in the cockpit as a result of
leaving a pair of pliers out in the rain for a week. What would be the
best way to remove the stain without damaging the gelcoat?

I do know that the sun will eventually bleach it our completely but it
would be nice to get rid of it sooner

Many thanks in advance

Matt

SV Mischief
PY 26, #129
Montreal


For removal of rust stains, use oxalic acid. This is a weak organic
acid, closer in strength to acetic acid (another organic acid, aka
vinegar) than to the inorganic acides like sulphuric or nitric acids.
It does an amazing job of removing rust stains completely.

Oxalic acid is available in many over-the-counter products (look for it
in the ingredient list) wood bleach, teak cleaner, Zud cleanser for a few.

The pure substance is a crystalline solid (kinda looks like sugar).
It is not very soluble in cold water, MUCH more soluble in hot water -
make a warm or hot water solution and simply blot it on.

Oxalic acid is the tart flavor in rhubarb.

Oxalic acid is a poison. Don't drink solutions of it, don't let your
fingers get into your mouth or eyes if they might have the solution or
dust on them. Oxalic acid is the primary metabolite of ethylene glycol
in the body, and is the primary reason that ethylene glycol is poisonous
when ingested.