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Discussion Starter · #1 ·
Why are aluminum mast painted?

If you answer to protect from corrosion, then why is the inside of the mast not painted? The interior would get salt spray from all the holes in the mast and would not get the benefit of a rain shower or wash down. Now if the mast is anodized, I could see how that could provide good corrosion protection- and look good for a long time. Paint seems to be just a maintenance problem.

My mast is painted, and needs to be repainted. Should I just strip the paint and leave as bare aluminum?
 

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Discussion Starter · #3 ·
Because they look pretty?
Ok, since I do not care about looks, I should just strip all the paint from the mast and leave as bare aluminun?

Actually, I think bare aluminum looks better that paint, if paint is there just to look "pretty". I like function over looks, and if a bare aluminum mast functions as well as a "pretty" painted aluminum mast, I would go bare.
 

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Painting aluminum doesn't make a whole lot of sense IMHO. When paint starts to delaminate, water gets underneath and the aluminum corrodes with little chance of the native oxide reforming. I prefer anodization.

I suppose paint looks good and if the prep is well done, it can last quite a while, but still... I just had to redo the boom and part of the mast, not a fun job.
 

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Casy, have you looked down the inside of your mast? Have you seen corrosion? How many "holes" do you have? Don't know who built your mast (Charleston? Selden?) but chances are there is some sort of protective coating on it which would be sufficient for the inside (at least when the mast was built.) The exterior of the mast really gets weathered and should be annodized or painted. Scatches in either should be touched up. Stripping the paint would also strip any annodization. Repainting the mast is your cheapest and most effective option. If you have a lot of "holes", I'd tap them and screw in a short shank screw in them (after bedding). Not only do holes weaken the structure, but like you said, can introduce salt spray/fog corrosion into the interior of the mast.
 

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Daniel - Norsea 27
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I have seen some boats that have bare poles. I believe many are painted to give them a clean finished look for those new boats. I actually plan on repainting mine someday.
 

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Discussion Starter · #7 · (Edited)
Casy, have you looked down the inside of your mast? Have you seen corrosion? How many "holes" do you have? Don't know who built your mast (Charleston? Selden?) but chances are there is some sort of protective coating on it which would be sufficient for the inside (at least when the mast was built.) The exterior of the mast really gets weathered and should be annodized or painted. Scatches in either should be touched up. Stripping the paint would also strip any annodization. Repainting the mast is your cheapest and most effective option. If you have a lot of "holes", I'd tap them and screw in a short shank screw in them (after bedding). Not only do holes weaken the structure, but like you said, can introduce salt spray/fog corrosion into the interior of the mast.
I have looked inside my mast as best I can and see no corrosion. The mast is deck stepped and I can inspect the inside of the base- no corrosion issues. I also have interior haylards (total of 7)- which means quite a few holes (actually slots) both at the top, middle and base of mast. the mast also appears to have many holes (about 1/8 inch diameter) along the first 1/3 of the mast track- I am thinking this might be fore a storm tri sail mast track that was never fitted.

As far as the make of the mast, I am not sure, the mast was first stepped in Australia in 1978. There is no name plate or number I can find on the mast. The exterior was originally painted and then painted one time. There are a few areas under the paint where corrosion has formed- nothing significant.
 

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There is an anodizing process that imparts color to the metal. So you can have your mast anodized and the looks of painted too.

Daniel, check out AAA Custom Anodizing & Metal Finishing. They are in Piney Flats TN and have a tank 39 feet long. I'm not connected with them at all but they did anodize the spreaders and will do some electro polishing on some stainless steel parts for me.
 
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Here's to your question. There ARE manufacturers that sold every boat they made with a painted mast. I know, I own one. Allmand boats were sold with white masts. There were many San Juans (Clarks) sold with "matching or contrasting painted masts".

Then comes the refurbishment... as stated it's easier for us DIY'rs to clean and paint as not many of us have the facilities to completely strip and dunk a mast in solution etc.. I just got done refitting my mast which included a sanding, treating and repainting. Turned out beatiful. :) If you scuff your paint and it mostly holds... paint it. I don't think you'll be happy with the way it will look after you've sanded all the paint off of it. You'll have sanding marks and swirls etc.. Now you could spend months sanding all the paint off and hand sanding down with finer grits to give you that new bare aluminum mast look... but that isn't going to happen - you want to use your boat! ;)

PM me if you want good particulars on how to do it.

Dave
 

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Daniel - Norsea 27
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There is an anodizing process that imparts color to the metal. So you can have your mast anodized and the looks of painted too.

Daniel, check out AAA Custom Anodizing & Metal Finishing. They are in Piney Flats TN and have a tank 39 feet long. I'm not connected with them at all but they did anodize the spreaders and will do some electro polishing on some stainless steel parts for me.
Thanks, I'll look into it. I was thinking to repaint to a bright Yellow. Figured it would be a good way to stand out at an achorage. :D

I think I need to have my spreaders taken care of. The ends are not looking too well to me.
 

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To add weight aloft.

Why are aluminum mast painted?

If you answer to protect from corrosion, then why is the inside of the mast not painted? The interior would get salt spray from all the holes in the mast and would not get the benefit of a rain shower or wash down. Now if the mast is anodized, I could see how that could provide good corrosion protection- and look good for a long time. Paint seems to be just a maintenance problem.

My mast is painted, and needs to be repainted. Should I just strip the paint and leave as bare aluminum?
 

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I like the look of red hulls, not sure about red masts. Call me a traditionalist, but if it was me, and the stick was pulled for maintenance anyways, I’d be (light) sanding, priming and painting white. Not sure that I like big, open exposed slots on my spars. Have you considered putting in halyard exit plates to “fill – in” those open slots? Harking and others make these plates. Is the corrosion you see near screws or rivets? Without seeing your boat, I’d guess you have a little galvanic corrosion going on under the paint. I would clean up/sand. Then prime with aluminum primer and then paint the top coat. Tap and screw in “plugs” for your trysail hole pattern. You might want to drill a tiny weep hole at the base of your mast (rear side). My guess is you have accumulated a lot of water in it since the last time the stick was pulled.
 

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Discussion Starter · #13 ·
I like the look of red hulls, not sure about red masts. Call me a traditionalist, but if it was me, and the stick was pulled for maintenance anyways, I’d be (light) sanding, priming and painting white. Not sure that I like big, open exposed slots on my spars. Have you considered putting in halyard exit plates to “fill – in” those open slots? Harking and others make these plates. Is the corrosion you see near screws or rivets? Without seeing your boat, I’d guess you have a little galvanic corrosion going on under the paint. I would clean up/sand. Then prime with aluminum primer and then paint the top coat. Tap and screw in “plugs” for your trysail hole pattern. You might want to drill a tiny weep hole at the base of your mast (rear side). My guess is you have accumulated a lot of water in it since the last time the stick was pulled.
Agree, If I paint, the mast will probably be white or maybe platnium. Some corrosion near rivets and some under the paint where the paint bond broke and water gets under the paint and cannot be washed away. As far as the base of the mast- there is actuall about a 2 inch by two inch hole in the base that allows water to drain out. During wash downs I actually shoot the water right into the mast (through the halyard exits) to rinse it out.
 

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Most 'bare' aluminum masts are in fact clear anodized.. Aluminum will oxidize to a stable outer layer, but it's usually fairly rough/dusty when you rub or touch it. An example of that could be the rough, pimply surface on a below decks aluminum backing plate that didn't quite stay dry.
 
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Discussion Starter · #16 ·
Most 'bare' aluminum masts are in fact clear anodized.. Aluminum will oxidize to a stable outer layer, but it's usually fairly rough/dusty when you rub or touch it. An example of that could be the rough, pimply surface on a below decks aluminum backing plate that didn't quite stay dry.
My mast base tabernacle is a fabricated from aluminum. Never was painted. Can be seen in the pic. It is like you say rough, but has developed a tough protective skin.
 

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The corrosion resistance of aluminum varies tremendously, depending on the specific alloy. Think about a cheap generic bracket (Home Depot style) that develops the white pox in a few months, and compare that with the hull on an Ovni, which just forms a nice protective layer of dull gray oxidization. I don’t know but I would bet that the extrusions that are used for most spars aren’t anything special.

BTW, all that fancy colored anodizing, starts out as clear and then gets a dip in the dye tank. At least that’s what I was told by the company that used to do all our anodizing. That’s why it fades, and red is the worst.
 
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Discussion Starter · #18 ·
The corrosion resistance of aluminum varies tremendously, depending on the specific alloy. Think about a cheap generic bracket (Home Depot style) that develops the white pox in a few months, and compare that with the hull on an Ovni, which just forms a nice protective layer of dull gray oxidization. I don’t know but I would bet that the extrusions that are used for most spars aren’t anything special.

BTW, all that fancy colored anodizing, starts out as clear and then gets a dip in the dye tank. At least that’s what I was told by the company that used to do all our anodizing. That’s why it fades, and red is the worst.
Just did a quick search and found some interesting information:
Boatbuilding In Metal

Also, marine aluminum alloy would be 5000 or 6000:
Aluminum Alloys

I have check selden website and cannot find what aluminum alloy they use.
 

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I cannot really answer your question but I just repainted my 35 year old 50 ft mast this spring. Last year I was seeing a lot of corrosion and minor pitting around all the stainless steel screws and stainless hardware (e.g., around the winches, halyard plate covers, boom attachment, shroud attachments, etc.) so I labeled everything and removed all the hardware, which was no easy task. I used an impact driver, heat, penetrating oil and a lot of patience to get all the old frozen fastners off. I then sanded all the paint with a 50 grit sandpaper on a Festool Rotex RO 150 with vacuum, a wire wheel via a Makita electric drill in the recessed track and a dremel via wire wheel in the track too, and of course some hand sanding. Added three coats of Interlux gray barrier paint as the primer and three coats of White epifanes 2-part polyurethane via the roll and tip method. Came out okay looks even better from 30-feet :) Added many new fastners prepped with forespars lanocote, in fact with all the stainless steel I added a thin coat of the Lanocote. I painted the mast to help slow the corrosion process, it seemed like the thing to do, probably wasn't. Moreover my boat is in the same harbor as the Secretary of State's so I thought I'd spruce her up a bit giver her that Bristol look. My Catalina 22 and Oday javelin have anodized masts, never been painted and never will as long as I own them and both are probably 40 years old or more and look great.
 

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Selden currently uses 6082 alloy. 6061 is the somewhat traditional alloy because it is a primary alloy in aircraft building but has 3-4 times the copper as 6082. The extra copper makes 6061 a lot more suseptable to corrosion.

A lot of class societies have disallowed 6061 because of the corrosion problem, but this is a relatively recent change (10 years or so). So what alloy any particular boat has is a bit of an open question.
 
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