Painting stainless steel "P" bracket

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lydiamight

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Painting stainless steel \"P\" bracket

At the winter lift out I have noticed a small amount of corrosion on my stainless steel "P" bracket--hopefully this will be stopped by the fitment of anodes to the bracket. I have taken the bracket down to the bare metal and am wondering what to paint it with before I apply some A/F. I know its stainless but I still think some form of paint protection would be of use. Any suggestions as to the best method of protection would be appreciated---or should I just apply some A/F?
 
Re: Painting stainless steel \"P\" bracket

If it is actually stainless then painting it would be the worst thing to do. Stainless needs oxygen to maintain its stainlessness, and painting it will deprive it of that. best leave it clean and bare - after all, thats what thousands of boats do with their prop shafts!
 
Re: Painting stainless steel \"P\" bracket

I would think it most unlikely your Dehler 36 has a stainless-steel P-bracket ..... unless one has been fitted subsequently? They are usually (hopefully) bronze. Much debate about whether or not to paint bronze, but from practical experience certainly recommend they should be bonded to anode(s).

Vic
 
Re: Painting stainless steel \"P\" bracket

What a big problem a stainless steel 'P' bracket would be. As Birdseye says it needs to be open to oxygen in the water. If barnacles adhere to it they will start it corroding itself. Stainless steel is the worst possible metal to use below the water line as it is the only metal able to set up it's own personal galvanic corrosion cell.
Poilsh it to high gloss to prevent barnacles adhering and then bolt on an anode to help slow any corrosion processes that start. Think about changing it for bronze in the future.
 
Re: Painting stainless steel \"P\" bracket

Stainless steel technically is non paintable. No paint manufacturer to my knowledge makes a primer which they can recomend or guarantee that will adhere to stainless.

However the best method to paint stainless steel for use under water is as follows.


Scratch up the surface with a grinder to P80, or teh equivlent of 80 grit sand paper. Do not grind the metal away but provide a scratch for the paint to bond too. without scratching the surface to provide a key, any paint should literally peel off.

Wash the stainless with an epoxy preperation solvent to remove any grease or contamination.

heat the stainless to about 60 degrees with an electric gun, not gas as teh flame contains contaminants which could effect the surface to be painted.

Find an epoxy primer suitable for underwater use which has an application temperature of more than 60 degrees. Most epoxy manufacturers make this. Many epoxies can be applied to surfaces at this temperature. Just check the manufacturers data sheets.

brush on one coat and then when that coat has tacked off (approx 5 minutes due to the high temperature) apply another coat. The logic behind this is that the pores of the stainless are expanded enough to allow some of the epoxy to soak into the steel. when the cooler paint hits the surface and as the stell comes back to ambient temperature it cools and contracts locking the epoxy into itself. The second coat applied (Wet on Wet) allows a chemical bond between the two coats. Epoxy bonds better chemically wet on wet rather than after it has had time to dry.

A couple of hours later apply 1 coat of antifoul. This will also chemically bond to the previous coat of epoxy. This way you have now chemically bonded the antifoul to the pores of the stainless.

Ensure the anode is connected prior to painting but mask the anode so as not to get any paint on it. This way the anode has an electrical bond to the surface. The anode will not work if it is not in contact with the metal, ie obscured by or with paint.

This method is the best way to antifoul stainless. Do not get the stainless to hot or it will deform or loose its shape particularly if it is flat sheet.
 
Re: Painting stainless steel \"P\" bracket

Like you I am having to consider painting the P bracket on my dehler 1988/89 vintage . I wonder if it was a dodgy batch of stainless.
 
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