Looking for advice on "Restoring" an old aluminium boom.

[Northbeach]

I own a '73 Cal T/4 that has spent the last 32+ years outside. The boom & mast are aluminium and have lost their original shine a long time ago. How does one go about bringing back as much shine as possible? My plan is to start on the boom and then eventually tackle the mast. I have cleaned up the boom as much as possible with a nylon brush, the best marine cleaner I could find, soap and water but what is the next step?

[sailaway21]

You can polish up both mast and boom but the shine will quickly fade as the aluminum oxidizes. The oxidation actually protects the aluminum, but is unsightly and comes off black to your hand. The only way to preserve the look is to have it re-anodized. The various clear coats available flake off under use and you end up with even more of a project fixing it next time.

I painted mine with Interlux Perfection. I chose white, but there is a wide selection of colors. Clean the aluminum up using wet/dry paper removing all of the remaining coating and oxidation. Wipe down with acetone a couple of times and then prime with zinc chromate primer. Perfection is a two part epoxy paint and, if used, read and follow the directions carefully. Especially the recoating times so that each coat will bond to the previous one. If you select Perfection I would recommend using a very short nap roller, similar to one used for rolling epoxy resin, and put the coats on lightly. Too heavy and you'll have a running mess you'll never get right until you sand it off. Spraying would be ideal, but requires a fresh air or self-contained breathing apparatus due to the cyanide in the paint. Roll and tip works fine.

The only thing I would have done differently on mine was I probably would have etched the aluminum better with phosphoric acid prior to priming. Read about that about a week after completion of the job. The paint seems to be holding up fine after 1 year and it looks great. I hate the look of aluminum, even shiny, and so this was on my list to do for some time.

btw, mine is a Cal 21'.

Also I recommend Don Casey's latest book, Complete Illustrated Sailboat Maintenance Manual. You can find it at amazon for less than west marine, and it's quite good on these projects. He discusses this job in the book-good ideas on how to hang the mast while painting.

Good luck

[Northbeach]

Sailaway21
Thank you for the thoughtful responce. Painting the boom & mast never occured to me. I need to spend some time thinking that one over. I'll buy the book you recommended.

[wlcoxe]

I took the boom on my ODay 28 down to bare metal, primed it with aluminum outdrive yellow primer, and spray-painted it with white Rustoleum. It has held up well for four years.
Bill

[Faster]

We painted the mast and boom on our Choate 40 after stripping off a laquer-like coating. We then sanded everything, washed it a couple of times with vinegar to lightly "acid etch", then primed and painted with Awlgrip.

This was a fairly flexible mast and we were advised to paint as thin a coat as we could get away with to avoid the paint cracking afterwards - wouldn't be a problem with the boom or a more robust mast section.

This really updated the look of the whole boat and the rig still looks great nearly 10 years later.

[Northbeach]

Ok, it looks like the running consensus is to paint the aluminum rather than trying to regain luster. I guess that's why forums can be great as they sometimes open up avenues that I would not have thought of on my own. I remember back in airframe & powerplant school (years ago) stripping down to bare aluminum a Piper Cherokee 6 (six passenger piston powered low wing airplane) and going through the various steps to repaint it. Thank you for the time you spent responding.

[TXS-ALAMO]

My rigger suggests powder coating over painting. But you have to have access to a firm that can take your mast length in their ovens. He says that here in the Houston area, it's actually cheaper than painting with Perfection.

[jones2r]

Be aware that powder coating is thick. Any areas where you don't want buildup should be masked before spraying. Removing powder coating is physical work.

[TXS-ALAMO]

It's supposedly more durable than paint. Could be because of its thickness? Anyway, I decided on Perfection because its a diy thing and cheaper for me.

[pigslo]

Powder coating aluminum must be done right as out gassing from the aluminum creates pits. Paint it!
pigslo