To paint or not?

shemandr · Sep 7, 2014

Unpainted is OK. Very soon a layer of oxidation forms and more or less prevents further corrosion. Aluminum spars last a long time. I don't think I've ever even heard of one that failed due to corrosion.
But they will shed some oxidized aluminum when you brush up against them, and will leave stains on your sails. They are ugly - but that is subjective.
I would repaint if it were up to me, as I did on one boat I owned, but it isn't structurally necessary - for a decade or so.

centerline · Sep 7, 2014

I would probably spot paint the areas that dont have paint, using a method proper for aluminum.

the aluminum will take care of itself pretty well if it could maintain its barrier from oxygen, either by paint or by forming its own aluminum oxide coating, but when there is a lack of paint adhesion and water gets between the paint and the aluminum, it cant dry out quick enough and will set there like the droplet of water that it is and eat away at the aluminum because the droplet of water wont let the protective aluminum oxide form on the surface of the aluminum....

the very least you should do is remove the loose and scaled paint from the damaged area and allow it to breath. the oxide can then develop....

AWalker · Sep 7, 2014

Unpainted, and non anodized will turn ugly and stain things a dark grey color. Just repaint using a high quality paint.

Allan12210 · Sep 7, 2014

I think Centerline has the right idea, spot paint the areas where the corrosion and blistering or paint loss is occurring. That is usually in the vicinity of a stainless steel fastener (screw or through bolt). I prepped my own mast and then the yard painted it for me. When I got it back, I used nylon washers under the bolt heads and shroud tangs just to isolate somewhat the dissimilar metals and to prevent wearing through the new paint. This is where I had observed the most blistering of the paint and subsequent pitting. I also used anti-seize plumbing compound on all screws and rivets placed back in the mast. The mast had become severely blistered and pitted within its first 12 years. Now 17 years after painting and the treatment of the fasteners, it doesn't seem to show any of the previous degradation. One thing for sure, over time it never gets any better, and it may be possible for enough aluminum loss at a high stress point to fail as these spars get more ancient.

I've attached the procedure I was given as there may be some information of interest in the preparation for priming and painting.

Scott T-Bird · Sep 8, 2014

You may as well do the job right. Remove all fittings, bolts, etc. that can be removed readily (I left saddles that were riveted with ss rivets in place and worked around them). Sand off all paint to bare metal. Etch prime with a bare metal primer. Intermediate coat should be a 2-part primer over the etch prime. Finish coat with 2-part polyurethane. Most people roll & tip. I just used a high quality brush and came away with near flawless results.

There is no way that an un-anodized bare aluminum mast compares to a painted mast, which is done well. Reflecting upon the old paint on my mast, it was a cheaply-done job to begin with. Put a high quality paint on it and it will really look great.

25yearslater · Sep 9, 2014

I went the full route. Strip, Reanodize and powdercoat at Charleston Spars. Here is a link: http://forums.oday.sailboatowners.com/showthread.php?t=123244&page=29 and page 30 show the result.

bffatcat · Sep 10, 2014

to paint or not to paint

I dunno guys Guess Ill have to play the devil`s advocate again. Iv`e got a 39 year old aluminum mast on my vintage pearson 26w The mast is OK Its turned a dark gun metal colot. I havent noticed any flaking or peeling. My philosophy is as always IF IT AIN`T BROKE DON`T FIX IT

Charlie Jones s/v Tehani · Sep 10, 2014

I painted the mast on a 21 footer 11 years ago. Sanded, primed with Zinc Chromate, sprayed with two coats 2 part poly. No longer my boat, but it's in my marina- Still looks great

Chris Patterson · Sep 10, 2014

Aluminum is no harder to paint than any other metal. Scuff it, clean it, and jam it. The primer will dictate how long it lasts..

jibes138 · Sep 11, 2014

Chris Patterson said:
Aluminum is no harder to paint than any other metal. Scuff it, clean it, and jam it. The primer will dictate how long it lasts..

You should coat the mast with Alodine and then paint it. Alodine is a chemical process that is used instead of anodize to provide a highly corrosion resistant surface. You brush it on then rinse it off. It is used in aerospace where you need electrical conductivity and to touch up minor scratches on anodized parts. You can buy it over the internet and is fairly cheap. Great for paint adhesion also.

Gunni · Sep 11, 2014

If you paint your aluminum spars and fittings you are stuck with the maintenance, unless you remove the part strip and re-anodize. Once the paint coating barrier is broken corrosion accelerates behind the adjacent coating. So you need to keep everything properly coated. If you sand he spar, you will likely remove the anodization layer, exposing the raw alloy. The extent and type of corrosion depends on the alloy chemistry.

tommays · Sep 11, 2014

At some point on a J24 it becomes a damage control issue and the mast will fail if it is not taken apart and serviced

ON MY CAL 29 THIS IS not THE CASE AND IT DOES FINE NAKED due to completely different construction and methods of holding things one

Everything is bolted to a welded on plate so none of the SS fittings affect the base metal of the mast

It was almost like having a new boat after it was done and the performance was much better as many issues with sheave bushings and lights were made better than new

Its nasty nasty nasty stuff to work with

To paint or not?

dbecker68

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shemandr

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centerline

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AWalker

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Allan12210

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Scott T-Bird

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25yearslater

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bffatcat

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Charlie Jones s/v Tehani

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Chris Patterson

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jibes138

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Gunni

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tommays

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