rust converter compatability

[wharfrat]

My sailboat is equipped with a Volvo Penta sail drive unit. Where the unit goes through the bottom of the boat there is a large steel ring holding the unit in place. The unit is rubber seal mounted. That is to say between the unit which is about 10 inches in dia., and the ring which is about 12 inches in dia., there is a rubber seal. In section it looks like a camel’s hump. This rubber seal supports the drive unit as well as the aft end of the engine. In theory if one was to take a sharp awl and stab this seal, down you’d go faster than you could say Jacque Cousteau.

This ring is heavily corroded after 25 years of total neglect. I got off the loose cakes of rust build up and I am about to apply a rust converter. Probably Plasti-Kote Rust Not

Am I going to have any reaction to the rubber should I get it on the rubber? (I will be using the brush on bottle)

Thanks to any and all responses

[Bob Smalser]

Dunno about your miracle goop, but all effective rust converters I am aware of are mild phospohoric acid preparations. The rubber will stand a dose of that if it is washed off with reasonable promptness....but if it seeps between metal and rubber and sits there, which is the likely scenario of derusting without dismantling, it'll likely do harm.

I wouldn't try anything at all without dismantling the unit. Then the metal can be properly parkerized/painted or galvanized on 100% of its surface area, and the fasteners and rubber replaced. I'd think anything less would be a waste of time.

[RGM]

Follow Bob's advice. Anything short of that is a "band aid" approach. That's a bad spot for a band aid. Additionally, most paint manufacturers won't stand behind their products 100% if they've been applied over a phosporic acid treated metal.

[ 07-18-2004, 02:05 PM: Message edited by: RGM ]