painting yer prop

[Guest]

After the plastic coating has pealed off the volvo prop, I have sanded down well, primed, sprayed and each year the paint has just come off after a few weeks revealing bare Al. Each year I spray with more exotic materials but I guess I'm stuck with a fundamental of how to get that first coat to stick while 'god knows what water speed' is rushing past. what am I doing wrong. David

 

[Guest]

Try using Etch primer first on the bare ally, thats what is used on Land Rovers ETC and they are all ally. It actually etches into the outer surface of the metal hence the name. Available from all good auto paint shops.

 

[Guest]

I have had the same problem in the past, and have finally resolved it (mainly as a result of 40 years in engineering). Most standard paint systems adsorb water, swell then become unstuck.

Fundamentally there are two solutions, these being:-

1/ Etch primer+ two coats of 2 part epoxy primer-filler + 3 coats of 2 part epoxy gloss ( rubbed down between coats).

2/ Shot blast or severely roughen prop to a depth of 1 thou ( surface will have a very rough, frosted appearance). Liberally coat with a two part epoxy resin (can be a filled and coloured version). Apply a further coat, sanding the first. The resulting finish will have a high gloss.This is the best, and will never come off, except of course at the blade tips.

There are some exotic epoxies which are hydrophobic, and are capable of reducing the power requirements- but that's another story.

 

[Guest]

Great response Stuart, any trade names you can give for the epoxy paints. David

 

[Guest]

David, there are several, but start with 'Trimite' in Uxbridge,on www.trimite.com. However if you use a search engine, try putting in 'epoxy paints' and you'll get lots more with marine links.

If you want to go down the epoxy resin route, then Belzona have the most sophisticated range. @ WWW.belzona.com

Hope this helps- good luck, Stuart