The New Boom and Gooseneck (Page 4)
This page was last updated on 28 August 2004.

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Painting the New Aluminum Boom
Originally, I had planned on painting the new boom in a week or so.   However, when I ordered the etching and painting supplies I needed late in the afternoon of the day I picked up the boom Thursday), I realized that they might arrive early enough the next day for me to jump right on the painting project.  The next-day truck delivery (for free) is perhaps the greatest benefit for me of working with wholesale suppliers.

boomslung.jpg (36517 bytes)Friday morning, I began preparing for the upcoming painting process by clearing out part of the shop (moving out our trailered 23' Lyman), and suspending the new boom between two large sawhorses to allow the entire surface to be reached and painted.  I hung the boom with some scrap wire, one piece at each end.  At about the time I finished with these preparations, the delivery truck arrived with my etching and painting materials, so I got right to work.

Before beginning, I laid out all my materials and ensured that I had everything required.  The etching and painting process I planned to use, as prescribed by the US Paint website and Awlgrip users guide, dictated a specific, time-sensitive order in which to proceed, and once the process was begun, I would have to follow it through to completion on that very day.

productsready.jpg (31787 bytes)

I began by cleaning the new spar with commercially available degreaser and a light Scotchbrite pad, to remove dirt, oil, and fingerprints.  I rinsed the boom thoroughly to remove all traces of the detergent, then dried the surface and solvent-washed it with Awl-Prep solvent.

etched1.jpg (36550 bytes)Next, I chemically etched the boom using Alumiprep 33, an acid treatment designed for the purpose.  Wearing rubber gloves, I diluted 1/2 cup of the acid with 1-1/2 cups of water, then applied it to the boom using a Scotchbrite pad, beginning at the bottom and working my way up.  Since I was working indoors--albeit with the large shop doors open--the work area was out of the direct sunlight, so I didn't have to worry too much about the material drying too fast; it's not supposed to dry on the surface, so I cleaned about 1/3 of the boom length (both sides), let the material work for a minute or two, then rinsed off the area with clear water.  Once each section was done, I moved on and cleaned the next portion, till the entire boom was cleaned and etched.  I rinsed the whole thing thoroughly, including the inside, as the acid can cause corrosion and deterioration problems if any is left behind.  The product directions indicated that the rinse water should be free from breaks, leaving a constant sheet of water behind.

alodine3.jpg (43557 bytes)While the boom was still wet from rinsing the Alumiprep 33 away, I applied a coat of Alodine 1201 conversion liquid, a nasty, gold-colored chromate product that is designed to seal the aluminum and provide superior corrosion resistance and adhesion of subsequent products.  With a small amount of the foul-smelling liquid in a cup, I applied it to the boom using a chip brush, again working from the bottom up.  I made sure to get the material on all surfaces, and, as before, completed the application in sections, this time about half the boom at a time, before rinsing off the material as directed.  Again, it was undesirable to allow the material to dry on the surface before rinsing:  doing so would require reapplication of Alumiprep 33 before continuation.

alodine1.jpg (20634 bytes)Once I had treated the entire boom with Alodine, I rinsed the entire thing carefully, ensuring that I rinsed the mainsail foot slot, the corners around the outhaul sheave, and the inside of the boom, particularly at the ends.  I raised one end of the boom to promote drainage from within, and flushed the whole unit repeatedly; again, I was looking for a constant sheeting action of the rinse water with no breaks.  The Alodine left behind a subtle gold tint on the aluminum.

When I was satisfied that I had rinsed thoroughly, I left the boom to dry.  To assist in removing standing water from the slot and corners, I used the air hose from my HVLP turbine to blow away the excess water (since I don't have compressed air in the shop), and dried the surface as much as possible.  Then, I left the boom to dry thoroughly for some time, though only as long as necessary, since primer application was to occur as soon as possible after the boom was dry.

nukeprimer.jpg (54615 bytes)I chose Awlgrip 30-Y-94 yellow anticorrosive primer, a vile-colored product reminiscent of what one might imagine water runoff at Chernobyl might have looked like.  I mixed the primer base  1:1 with the appropriate converter and allowed the mixture to prereact for 15 minutes as directed before reducing with a further 1 part of T0006 primer reducer.  I then poured the very thin resultant product into my spray gun and spray-applied a single coat of the primer, as directed.  The primer was extremely thin and ran easily, but I managed to achieve the coat required with minimal problems; I carefully dabbed away some drips at the boom ends, and decided that a couple small curtain-type runs were not problematic enough to worry about; the material was so thin to begin with that the curtains were nearly unnoticeable.  

boomprimed.jpg (32989 bytes)I left the primer coat to dry for a little over two hours--the minimum prescribed time--before continuing.  Topcoats could be applied anywhere between two and 24 hours following the primer application; if more than 24 hours elapsed, the primer would have to be sanded and the boom recoated with Alodine, then reprimed, before continuing.  Fortunately, I was unconcerned about the 24  hour limit, as I had all intentions of completing the job as soon as possible.

boompainted1.jpg (32301 bytes)When the primer had dried sufficiently, I prepared to spray the final topcoats.  I chose Awlgrip Snow White for the spar, as it matches the color of Glissando's decks; plus, I just like the color, as it is clean and crisp while somehow maintaining more warmth, and less starkness, than pure white, though with no yellow or bluish tones either.  I had half a gallon remaining in stock.  (Later, once the mast was unstepped at the end of the season,  I planned to paint it as well.)

boompainted3.jpg (28064 bytes)In the space of a little over an hour, I spray-applied two coats of Snow White.  Because of some orange-peel issues I had experienced in previous projects using my HVLP spray equipment, I used a slower reducer this time, one that would allow the paint more time to self-level properly before kicking.  I was pleased with the results:  there was virtually no orange peel in the surface this time.  I applied one coat, allowed it to partially cure for about an hour, then applied the second--and final--coat.

aftendpainted.jpg (22621 bytes)     fwdendpainted.jpg (29214 bytes)

The next day, I returned to inspect the finished product.  I noticed that there were a few drips that had formed on the bottom of the boom, where the paint had run down and collected.  I wasn't sure how to deal with it:  they weren't that noticeable, but I wondered if they would drive me nuts once the boom was installed on the boat.  They would only be noticeable under sail:  when the boat is at rest, the boom is of course covered by the flaked sail and sailcover.  I decided to ponder the issue for a short while before deciding whether to sand the drips out and repaint, or to leave it be and chalk it up, one way or another, to good experience, lessons learned, and things not to do again.  Painting the bottom portion of the boom was decidedly difficult, and it was easy to overload the area with paint, which is what seemed to happen in this case.

In any event, the drips (maybe 10 separate drips) were not a big deal, and my inclination was to leave well enough alone--and to simply be extra careful in the future when painting the mast.  We'll see.  For now, the boom painting was complete.


Glissando, Pearson  Triton #381

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