Mast, Paint or leave necked

[heart of gold]

So while I have the mast down and in the back yard for a refit, I want to make it look a little better. I've read that to take it down to bare aluminum and leave it that way, is a possibility, any comments? If I paint, could a guy just scuff up the existing paint, and re top coat it with an epoxy? and if I go that way, can I just take out the corroded areas to bare metal, prime them first before painting the whole mast? Looking for advice from you who have experience, Thanks, Ian

 

[Guillaume C.]

There are specials primers for aluminum, and the topcoat should probably be a one or two-part polyurethane paint (epoxy usually does not resist well to UV). Where the existing topcoat is still in good condition, it is usually OK to just sand lightly the surface. Sanding down to bare aluminum would be a long and boring job and depending on the alloy, it might leave an annoying surface that blacken your skin and cloth when you touch it (because it won't be anodized like bare-aluminum masts from factories)

You can check for more specific instructions from paint manufacturer, interlux product are easy to find

Some non-marine product can work just fine on aluminum also, in Canada I use Corrostop Ultra... (one-part poly)

 

[Old Skool Neil]

I've painted three masts myself. The first was in my youth on my Catalina 22. It was a quick sand, flat black Rustoleum rattle can job followed by a generous coating of clear liquid Johnson's floor wax. It was surprisingly durable.

The other two were my previous boat, a Westsail 32 that I built and my current boat, a vintage Catalina 30. I'd learned a little more so the painting process I used followed LeFiell's protocol (LeFiell is a mast manufacturer). My modifications/additions are in red.

• Strip all hardware to raw extrusion
• Tap sheet metal screw holes for future machine screws - no sheet metal screws on finished product
• Sand lightly with 220 grit for smoothness
• Soap and water wash
  **The following steps are time critical, must be done within 1/2 hour of each other**
• Acid wash with Alumiprep 33
• Apply Alodine conversion coating
• Apply strontium chromate primer
  **End time critical operations**
• Apply suitable primer for top coat
• Wet sand primer with 320 grit
• Apply linear polyurethane paint
• Apply minimum 3 coats paste wax
• Reassemble with NOALOX on all fasteners and silicone rubber gaskets under all foot mounted hardware

The timed operations are to prevent the formation of oxides during the clean raw aluminum period. NOALOX is an anti-oxidant compound used in the electrical industry on aluminum wire connections. It virtually eliminates dissimilar metals problems and is readily available at Home Depot. The silicone rubber gaskets (material available from McMaster-Carr) prevent moisture from collecting under hardware bases like winches and spreader brackets.

edit:
Alumiprep 33, Alodine and chromate primer are available at Aircraft Spruce (California, Georgia and Canada).

 

[centerline]

if the paint original is in decent shape, you dont need to go thru all the hassle of sanding it all down and doing the prep work to the aluminum...

if the paint is still firmly attached to the aluminum, someone else already did a good job of doing the prep... so all you need to do is use a course scotchbrite pad and scuff the surface of the existing paint and make sure its clean and oil free.... almost any paint that you would choose to use on it will adhere very well the the scuffed surface of the original paint...
if you take it to bare aluminum, its becomes way more intensive to get long term adhesion from any type paint you would put on it....

 

[heart of gold]

Thanks guys. From your input and some research, I have a plan. If it turns out, I'll post pics.
Merry Christmas and a cruising New Year. Ian

 

[Nelsonhow]

I removed all the pain from my h30 Kenyon mast with an orbital sander. Re bedded all the fittings, replaced the electric and VHF cable and running rigging. . Then I buffed the raw aluminum with white car compound and put on 3 coats of paste wax on top. That was 4 years ago. Still looks great.