Painting Aluminum

[atoll]

try taste the soda or get some ph sticks,a strong alkali would not be good on alloy.

unfortunately the stainless will win,judging by the pitting i would say the allumilium is also of not a very good grade,would really reccomend removing stainless fittings,using an ally filler or building up damaged sections by welding.

then refitting stainless using plastic gaskets,monel rivets and plastic sleves where through bolted

[David M]

Leave it bare aluminum if you can tolerate it. Paint over aluminum eventually blisters no matter what you do.

Anything stainless that needs to make contact with the aluminum, bed with Tef-Gel. That's what I noticed the pros in the yards are doing. Any primer they use is epoxy strontium chromate applied thin over brite (clean and unoxdixed) aluminum.

[Bergovoy]

i saw a product called lizard skin or something like that... it is clear and wipes on.. and is supposed to protect bare metals...might not last as long in marine environment but you can apply it easily and often...

also there is a process called CO2 blasting..

[Cheechako]

Originally Posted by akio.kanemoto

Hello gentlefolk,

OK, I'm finally up to the point that I am about to start something - either I sodablast and leave it, or paint it.

Removing fittings doesn't look like it's much of an option - there are a lot of things fitted from the inside of the mast and thus removing/rebedding doesn't look like a winning solution.

I'm leaning heavily towards sodablasting and leaving unpainted.

Having said that - I've finally gotten around to taking some pics - please let me know what you think:

https://sites.google.com/site/mastcorrosion/pics

...the entire mast (except for right at the top) is covered in bubbling where not flaking... and as you can see, it's not pretty.

Thanks!

Looking at your pics , the finish looks pretty loose at this point. Soda blast might be a great way to go if you can find someone to do it. I cant tell if there are any pits or deep corrosion around those stainless (?) fittings....but dont see any. I guess you could get by without removing them if there is no obvious corrosive pits. Of course a good mast rebuild would remove them, rebed them and replace all the fasteners. Dont be mislead though, probably every one of those screws will break off in the mast if you try to remove them, they will then have to be drilled out and either welded up or the fitting position moved enough to avoid the hole.

[jbrasfield]

my mast has steps that go up. it was once painted. Should I just sand off the flaking paint and then just leave it alone?

[Cheechako]

Hard question to answer, but that would be a good approach generally. The down side to unpainted masts is that they will discolor sails more then painted masts... but even painted ones get a lot of dirt on them...depending where you live.... and how close to roadways...