Radar mount coating lifting and blistering

[Tintin]

My scanstrut radar bracket is 3 yrs old.

I took it off the mast today to move it to a new boat.

The white paint coating has blistered off almost all over and flakes are falling off. Where the alloy is exposed the surface has started to chalk quite badly.

I reckon I need to sort it before remounting.

Any paint experts got any suggestions?
View attachment 39104

 

[Cloven]

Had the same problem on my wind genny.

1. Scraped/sanded off all the paint back to bare metal.
2. Prime with Hammerite special metals primer
3. Topcoat with Hammerite smooth white.

Still looking good after 5 years.

 

[Tintin]

Thanks Dave. Simple solution. Perfect for me 'cos I is simple

 

[pvb]

Scanstrut stuff is well designed and well engineered, but the paint finish is awful! You'd have thought that they'd have found out how to paint metal properly by now.

 

[Billjratt]

I used International garage floor paint on mine and it seems to have stuck.

 

[theoldsalt]

Had the same problem on my wind genny.

1. Scraped/sanded off all the paint back to bare metal.
2. Prime with Hammerite special metals primer
3. Topcoat with Hammerite smooth white.

Still looking good after 5 years.

I did exactly the same on my wind genny so can concur.

 

[Tintin]

Scanstrut stuff is well designed and well engineered, but the paint finish is awful! You'd have thought that they'd have found out how to paint metal properly by now.

I thought i may have had a dud one. Sounds like it is common.
To read their website about how the international boat community trusts them, and their years of experience, it surprises me that the finish is so piss poor.

I will give them a call today and report back. If hammerite or floor paint can do a better job then they have a production problem that they need to solve.

Lets hope they don't have the usual "don't care" attitude that British manufacturers often have (in my experience of trying to but british for 15 years for my business).

 

[charles_reed]

In fairness to Scanstrut - no-one appears to have solved the problem of plastic-coating aluminium castings - industrial myth is that plastic coating is the bees-knees for protection against weathering. However it appears to be quite useless against marine environments.
I've been told the way to do it is to go back to bare metal, apply a self-etching primer and then 2 coats of 2-pot polyurethane.
Doing that on a bought-in casting rather than quick and easy powder-coating is likely to quadruple the price.

 

[Cloven]

I thought i may have had a dud one. Sounds like it is common.
To read their website about how the international boat community trusts them, and their years of experience, it surprises me that the finish is so piss poor.

I will give them a call today and report back. If hammerite or floor paint can do a better job then they have a production problem that they need to solve.

Lets hope they don't have the usual "don't care" attitude that British manufacturers often have (in my experience of trying to but british for 15 years for my business).

It does sound very poor for only 3 years use. The wind genny I referred to in post #2 was 12 years old when it needed repainting and even then it was not too bad. It was just that I had it home one winter to replace the bearings so did a repaint at the same time.