Advantages to Painting the Stick ? !

[phantomracer]

Originally Posted by thinwater

I've had both. I wouldn't paint it, since any corrosion that occurs will be localized to paint failures. General corrosion, over the length of the mast will have no bearing on usefull life, while localized corrosion will.

Ours was awlgripped in 92. Still looks brand new. not a single point of corrosion...yet anyway!

Not sure about paint, but I would recommend awlgrip from my experience anyway.

I am sure that prep work and ongoing care will make a big difference.

Not bad for an almost 20 year old mast!

[thinwater]

Originally Posted by phantomracer

Ours was awlgripped in 92. Still looks brand new. not a single point of corrosion...yet anyway!

Not sure about paint, but I would recommend awlgrip from my experience anyway.

I am sure that prep work and ongoing care will make a big difference.

Not bad for an almost 20 year old mast!

Very nicely done.

However, my last mast was 34 (yearly twice as old) last time I checked on it, all salt water. It was Algripped when new, and where the coating had chipped, there were craters. The coating was still good. I had another boat, even older (76') with no corrosion at all. My current boat is 97' and not painted, and seems perfect too.

The Algripped mast was sure pretty; that didn't mean much to me. But it was pretty. I'm just not convinced it is about longevity, which was the OPs question. I believe it is the opposite, if only slightly. A mast should outlast the boat, excepting electrolisis or rigging failure.

As long as there are no chips and the surface prep is perfect....

[anotherT34C]

For the mast, I nicely spray the bottom 8-10 feet or so, and take a brush to the rest. By definition, the rest only has to pass the 10-foot test.

[delmarrey]

The problem I see with masts in general is when the halyards are left to slap the mast in bad weather during storage, whether it be galvanized or painted. Especially if it has a wire halyard. Ever spring I have to climb my mast to clean off the moss, and doing an inspection while I'm up there..
Those who take down their masts for storage are preserving the masts, which would be a good reason to take them down (another ongoing thread). But like said above it only makes them pretty if painted. I've never seen one fail due to its coating.

[s/v Beth]

Originally Posted by GordMay

I wasn't doubting the efficacy of Zinc Chromate on aluminum, merely it's ready availability to the (non pro') consumer.
I haven't seen it on the shelves, lately.

I used it as a primer on my mast last year Gordon, so it was around in Washington state at that time.

[roverhi]

According to LeFiell, there is no anodizing tank for masts on the west coast. That's why they paint their sticks. Believe you can still get anodized masts on the East Coast.

I've never seen a painted aluminum mast that doesn't have some corrosion around SS fasteners after a few years. The paint seems to look pretty junk around a decade or so. I'd stick with anodizing if you can get it. My 40 year old anodized mast is going strong despite it's years. Yes there are marks from old halyards, etc. but it still looks presentable. Doubt a painted mast would still look acceptable.

[Wotname]

Originally Posted by Bucky205

Here is a link to NASA's technical paper on using Zinc Chromate to protect aluminum

http://ntrs.nasa.gov/archive/nasa/ca...1996043922.pdf

This paper (as interesting as it is) does not address using zinc chromate to protect aluminum; rather it it report on quote "Whether the zinc in the zinc-rich primer will provide sufficient galvanic protection to 2219 aluminum is the question that was addressed by this work". endquote.

2219-T87 aluminum is a very different product to an aluminum mast. Again quoting from same paper "The aft skirt is constructed from aluminum alloy 2219-T87. This high-strength aluminum alloy is age hardened primarily by precipitation of copper aluminide. (CU-AZ~), which is significantly more noble than the aluminum matrix, making the alloy susceptible to pitting corrosion by a microscopic galvanic mechanism. This dual galvanic effect makes the aft skirt extremely susceptible to pitting corrosion."endquote.

So this is a good reference it you are attaching some 2219-T87 fitting to your aluminum mast but the OP isn't doing that and I suspect no one else is either.

[kismet]

Originally Posted by GordMay

Where can you still get zinc chromate primer (/w Chromium VI)?

I bought it a few years ago from Buddeke Paints, in Fells Point MD. a few years ago. I do remember them asking if I was a commercial operation and they did not want to sell it to just anybody.

[waikikin]

Originally Posted by kismet

I bought it a few years ago from Buddeke Paints, in Fells Point MD. a few years ago. I do remember them asking if I was a commercial operation and they did not want to sell it to just anybody.

This may be why..........
2. Effects on Humans: Exposure to zinc chromate can cause irritation, tissue ulceration, and cancer in humans. Inhalation of dusts containing chromates causes irritation of the mucous membranes [Rom 1992]. Gastric distress, olfactory sense impairment, and the yellowing of teeth and tongue may also result from excessive exposures to chromates. If exposures are prolonged, ulcerations of the nasal mucosae may occur as well as possible septal perforations. Prolonged dermal contact may produce ulceration of the skin. The increased exposure that results from an ulcer may result in renal chromate toxicosis, liver failure or death [Rom 1992]. Ocular effects including eye lesions, conjunctivitis, and keratitis have been associated with exposures to chromates [Rom 1992]. Prolonged exposure to chromates can cause chronic bronchitis, rhinitis, or the growth of nasal mucosal polyps [Rom 1992]. Exposures may also lead to chemical pneumonitis. Chronic exposures to hexavalent chromium compounds can cause lung and gastrointestinal tract cancer including cancer of the esophagus, stomach, intestines, and pancreas [Rom 1992]. Of six studies that examined the association between exposure to zinc chromate and lung cancer, five were cohort studies and one was a proportionate mortality study [ACGIH 1991]. In four of the five cohort studies there were also exposures to lead chromates. All of the cohort studies demonstrated an association between exposure to chromates and lung cancer. It was noted that because of the compounded exposures with lead chromate it was not possible to separate out the effects caused by each individual chromate compound [ACGIH 1991]. IARC has concluded that there is sufficient evidence for the carcinogenicity of hexavalent chromium compounds to humans [IARC 1990].

Of course this follows the rule that anything really good for the maintenance & repair of your boat will be bad for you.
Jeff.

[kismet]

Yea, that is why I did not have any for lunch..just used it to paint the centerboard.

[delmarrey]

Here is a list of zinc based paints by a well known supplier along with their MSDS.

Zinc Rich - Protective & Marine

[GordMay]

Zinc rich is not the same as zinc chromate.

[Blue Stocking]

Originally Posted by GordMay

Zinc rich is not the same as zinc chromate.

Awlgrip make it. Undercoated my guardrail to pedestal bracket with it last week.

[Ziggy]

Originally Posted by GordMay

Where can you still get zinc chromate primer (/w Chromium VI)?

You can get it from Sky Geek and also from other aircraft maintenance suppliers. I have bought stuff from them before--they are a great retail source for industrial type supplies in small quantities.

[Ziggy]

Originally Posted by pressuredrop

based on casual observation i would say that the majority of the aluminum masts i see are painted,
mine is not currently painted, and i have no problem with that, but is this something i should consider?

does painting the stick greatly (or even marginally) increase its lifespan?
is it a necessary layer of protection or merely aesthetics?

Actually, based on my casual observation, in the Northeast, most aluminum masts are left bare or anodized. I see no evidence that painting the spar increases the lifespan. If you see some trouble spots on yours, a periodic localized application of zinc chromate primer may help.