Powder coating peeling off steering pedestal

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NPMR

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The white powder coated paint is peeling off the steering pedestal in large chunks on our 4-season old Jeanneau.

I think it's a Lewmar unit. Anyone know the likely cause or what course of action to take to sort it out?

Tried to get a response from Jeanneau but they declined to help on the grounds of only one year's warranty on it. Not heard from Lewmar direct yet.

But it still needs to be dealt with whatever happens, this winter, before launching in May 2015.
 
Had the same problem with a bow roller some years ago and more recently a wind genny casing. Basically due to water getting behind the coating and then oxidisation of the aluminium beneath.

Only solution was to scrape off all the old coating and then repaint. Easy where it was flaking but hard work when it was still well attached. I used Hammerite special metals primer and then Hammerite smooth topcoat.
 
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If you can remove the pedestal and "dismantle" it you could have it re-powder coated for a pittance - check around your locality for powder coating companies.
 
davewarburton said:
Had the same problem with a bow roller some years ago and more recently a wind genny casing. Basically due to water getting behind the coating and then oxidisation of the aluminium beneath.

Only solution was to scrape off all the old coating and then repaint. Easy where it was flaking but hard work when it was still well added. I used Hammerite special metals primer and then Hammerite smooth topcoat.
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I would have thought a bow roller was an inappropriate item to be powder coated in the first place? The risk of chain impact cracking or chipping the coating and then its position up forward ensuring a regular supply of sea water entering the damaged coating would be a recipe for disaster?
 
cryan said:
I would have thought a bow roller was an inappropriate item to be powder coated in the first place? The risk of chain impact cracking or chipping the coating and then its position up forward ensuring a regular supply of sea water entering the damaged coating would be a recipe for disaster?
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Can't disagree with these comments, but that's the way it came with the boat. The Hammerite paint job as above lasted OK until I sold the boat although in places where the chain ran it was showing the Aluminium. Might have been better to have just left it as bare Al and let the surface oxidise.
 
NPMR said:
The white powder coated paint is peeling off the steering pedestal in large chunks on our 4-season old Jeanneau.

I think it's a Lewmar unit. Anyone know the likely cause or what course of action to take to sort it out?

Tried to get a response from Jeanneau but they declined to help on the grounds of only one year's warranty on it. Not heard from Lewmar direct yet.

But it still needs to be dealt with whatever happens, this winter, before launching in May 2015.
Click to expand...

Used to be in the metals business. Any coating on a non ferrous metal is problematic and particularly on alloy. The slightest breach in the coating ( scratch, chip, screw hole) allows corrosion to get in and because the corrosion products on ally occupy more space than the letal they come from, they peel off the coating. They gradually work their way under the coat.

Its a real issue with modern motorbikes - my BMW is notorious for it. The only sensible alternative is anodising which effectively is about making the corrosion product that does the peeling into a cosmetic finish.

If you cant get Lewmar to pick up the bill then your alternatives are either to patch paint ( abrade, two pack undercoat, two pack top coat) or top remove the pedastal, strip it down and take the item to your local powder coater for bead blasting and re -coat.

If its any consolation my pedastal is doing the same. The difference is that mine is near 20 years old.
 
I had to rebuild my column with new bearings etc so while it was in bits I had it recoated. First place said it couldn't be done and would peel (odd since it appeared to have been powder coated when attached to the boat some years before) but second firm said they did it all the time, but it needed an undercoat. Cost £48 for the column and the three associated parts. Looks well now.
 
The top plate on our pedestal was peeling so I grit blasted it and used central heating radiator paint, baked (much to SWMBO's horror) in the oven at around 80 degrees. Starting to get a bit scabby again after 10 years.
 
cliff said:
If you can remove the pedestal and "dismantle" it you could have it re-powder coated for a pittance - check around your locality for powder coating companies.
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Big word IF. I have some failed coating around fixing holes etc and would love to get it re-coated as you say. Its just the struggle I had to get all the wiring up the pedestal and grab bar to run the wheelpilot and plotter, I don't think I could face it again.
 
I did this to an 1980's pedestal 3 years ago.

I handed it to a local firm - they blasted it, and powder coated it after filling some small unused holes (from the old wheel pilot drive). Looks great now.

Warning - although they filled the tapped holes with rolled up paper, it would have been better to use screws to mask the threads as the paint is soooo hard to remove - some were difficult as I don't keep UNC taps. I also forgot to mention to them the bearing holes (in my case simple nylon bushes) - again time was spent 'fitting' the shaft and bushes.
 
Powdercoating is just paint, but applied in a different form.
Instead of having a liquid to carry the pigment and polymer, it is sprayed as a powder and heat cured. But there are many different polymers. If you just ask for "powdercoating" without specifying what you want, then that's similar to saying please "paint" it. Did you want emulsion? Varnish? alkyd enamel?
In powders, the common polymers used are polyester, epoxy and polyurethane. Polyurethane seems to do better in marine conditions.

But in common with all coating systems, its the pretreatment that makes the difference. The pretreatment is what will prevent or retard degradation and flaking after the inevitable scratch.
Any pretreatment with only one stage or two is probably inadequate, it should probably have 4-9 stages. (including rinses)
For aluminium, chromate is best, but manganese phosphate is good too.
If your powdercoater is proposing to only blast (bead or shot) then coat, go elsewhere. It won't last. Get genuine pretreatment.
 
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