Has anyone removed the paint from the boom? Ours is needing some attention and we are considering sanding the paint off and not repainting it. Based on research, it sounds like aluminum may be less prone to corrosion that way than if we repaint. What say you all? Any experience with this? Thank you.
You have paint on your boom?
Paul M
NS30U #211, Sandpiper
Cowichan Bay, B.C.
Hi
My boom was painted and it was peeling and flaking off. I used a Hyde paint scraper to get most of it off and then sanded it with a palm sander. I could not get all of the paint off at the ends where the joints are but it does look much better than it did.
David
Spray 1981 30C #93
South Dartmouth and Westport Point Ma.
Currently on the hard in New Bedford, Ma.
Thanks, David. We also have a 1981 Classic hull (#65). How long ago did you remove the paint?
Anita Bleick
NS 30C #65 - Ilse B
Bowen Island, BC
Hi Anita
I can’t be absolutely certain but I completed that project either in 2013 or 2014. The boat was on the hard after having the deck repaired/replaced.
David
Spray 1981 30C #93
South Dartmouth and Westport Point Ma.
Currently on the hard in New Bedford, Ma.
It is recommended that only emery cloth be used to sand aluminum as some sandpapers will leave residue behind which will initiate corrosion in the aluminum. Generally speaking, aluminum will build up a protective layer of aluminum oxide which will prevent further corrosion. I would be extremely wary of sanding the mast.
I see the manual recommends the mast be waxed when serviced. We just had our mast reinstalled after servicing and the rigger thought that completely unnecessary.
Peter, no worries about not sanding the mast. That is staying in all its original anodized glory. Do you have any information about what is and is not good sandpaper? The abrasive on emery cloth is typically corundite which is mostly Aluminum Oxide. I have heard this warning before and can find nothing online of any note. The best I can find is that garnet may leave bits behind in the material since it cracks under load. This reference was not aluminum specific.
Hi Scott, I have heard this for most of my life and am now trying to find the authoritative source! I hope to have an answer in the next few days. I do know that emery cloth is recommended by some of the airplane prop manufacturers, along with crocus cloth.
Peter Moodie
Nonsuch 30U #366 Catalyst
Sidney, BC/Winnipeg, MB
So I have it on good authority from an aircraft maintenance engineer instructor that sanding with regular sandpaper is not a good thing to do on aluminum. First problem, whatever product you use will most likely remove any anodizing or other protective coating from the Al. (On a highly stressed member such as the mast the scratches left by sanding could initiate fatigue cracking.) Sanding with crocus or emery cloth is acceptable.
The longer term problem with using regular sandpaper on Al is that some products contain iron oxide as an abrasive. Any iron oxide particles that are left behind embedded in the Al will initiate dissimilar metal corrosion. The damp and salty environment will accelerate the process.
I don’t think that any special process has been used on our masts or wishbones to prevent corrosion. They don’t appear to be anodized or to have been treated with alodine. Aluminum oxide is really a good protectant on its own and should be left as undisturbed as possible.
I hope that you find this explanation satisfactory.
Peter Moodie
Nonsuch 30U #366 Catalyst
Sidney, BC/Winnipeg, MB
Thanks much Peter. That gives me an entirely new rabbit hole to go down of Iron Oxide embedded in aluminum. 
Every year I take my mast and boom down. I wash both with Dawn soap and water, then dry both, apply a coat of Pledge liquid floor wax, then store inside. I also metal polish all SS and chrome. Bob Horne, 1989 N26C 249. Encore. Pocasset, MA.
The Nonsuch brochures indicate that the mast use anodized aluminium. I don’t know what they did with masts that the customer wanted painted. My research suggests that if you are going to sand aluminium you should aluminum oxide or silicon carbide paper and it should be fine grit.
Scott give this a read
Mark Powers
La Reina 26C
Vancouver, B.C.
This autumn, could you stop by and show me the proper way to do these chores?
Tom Sawyer
Kat Fish
PS I have a fence to paint too.
Thanks Mark, I had not seen that. The anodizing provides excellent corrosion protection on aluminum and you do not want to disturb the layer. The anodizing provides better adhesion for paint primers.
I am glad to hear someone does wax their mast. I would think that would also help to keep bad things from happening.
Peter Moodie
Nonsuch 30U #366 Catalyst
Sidney, BC/Winnipeg, MB
I had a roller furler on my previous boat with an anodized profile tube. When the anodized layer is damaged and plain aluminium is left, it’ll stain the headsail sail heavily. The sail will rub of the natural protection layer of the aluminium (the oxide that is) and that leaves dark gray to black stains on a white sail. I worry that a bear wishboom will do the same to your main. Therefore not a good idea imho.
mark
n36 #25
the Netherlands
David, have you experienced any marks or darkening of the sail as a result of sanding the boom? Many thanks for weighing in here!
Anita
Nonsuch 30C #65 - Ilse B
Bowen Island, BC
Good morning Anita
No. I have not experienced any marks or darkening of the sail as a result of sanding the boom.
David
Spray 1981 30C #93
South Dartmouth and Westport Point Ma.
Currently on the hard in New Bedford, Ma.
P.S.
I intended to add, that it would be a bear to remove black stains left on a white sail by bare aluminium.
Mark Powers
La Reina 26C
Vancouver, B. C.
That is very heartening! It’s so great that you’ve already done this so we can benefit from your direct experience!
Anita Bleick
NS 30C #65 - Ilse B
Bowen Island, BC
Just how many booms were painted? Was it an option?
Joe
C26 #156