Tag Archives: boom

Naked Boom Gets Primed

I sanded Madsu’s boom down to bare metal yesterday as I get ready to paint it.

After removing all the hardware I sited all the new/changed hardware and drilled and tapped the holes. I’ll use stainless machine screws instead of the self-tapping screws the previous owner loved. I’ve filled all the old holes with Star Brite aluminum epoxy.

The spar’s in great shape. I used a rotary sander to get the mast stripped down then use my Makita sander with 220 paper to prep it.

I used PPG DX 533 to etch the boom, then quickly followed up with PPG DX 503 conditioner. I got both at my local Lordco auto parts store – way cheaper than trying to find the marine version of same.

Once the DX 503 was rinsed and the boom dried, I immediately got the first coat of primer on. You can’t let the aluminum sit for any length of time after treatment because of oxidization (so I’m told).

I’ve opted for the tried-but-true-but-messy-and-smelly 2 part primer.

The Interlux 2 part is a lot more trouble – it’s really 3 part because even after you mix the 404 base with the 413 reactor, you still have to thin it 20 to 25%.

I wasn’t really sure how to work with the base – it’s the consistency of pudding – and you can’t pour it. I just stuck a mixing stick into the can and pulled it out, about an ounce or so stuck to the stick and I was able to use this ‘honey stick’ method to measure out what I needed.

I first tired a small foam roller – that was useless. Next I tried a disposable foam brush – that worked better. But a regular paint brush works best of all – the paint is thick and spreads beautifully, and there’s no worry about brush strokes showing up.

(boom after 1st coat of primer)

I left it overnight and sanded with 220 paper and got a 2nd coat on this morning. The weather’s been cold and I’d prefer it was a bit warmer to make sure the primer is really baked – I’ll give it a couple of days then do a 3rd base coat.

Now that I’m confident with is all going to work (!), I’ll strip the mast and get it primed, then I’ll topcoat both the boom and the main at the same time. I’m using Interlux Perfection, another 2 part, for the topcoat.

A quick survey of my mast hardware turned up a few issues. I was hoping to replace the spreader brackets, so last fall I ordered a stainless set from Catalina Direct.

Turns out my spreaders are 1 1/8th inch in diameter but the new brackets are 1 inch. Ugh. I’m thinking I’ll either leave the old brackets (which Catalina Direct claims are prone to unexpected breakage) or visit my new best friends at the metal store and pick up some 1 inch aluminum tubing and make my own ‘new’ spreaders.

Madsu Boom Mod

I’m getting set to paint the mast and boom on Madsu before putting her in the water this year.

But before I get there, I’ve got a few modifications to make, so I’ve commandeered the picnic table and set up for some serious mucking-about-time.

I started with the boom, stripping all the hardware so I can replace the self-tapping screws with tapped versions.

I’m also fixing the outhaul – the previous owner seemed to think a piece of line wrapped around a becket at the end of the boom was a proper outhaul. It drove me crazy last season, but since the main was pretty bagged, I put up with it.

Since I’ve got a brand new North Sail main for this season, and I was stripping the boom down anyway, I thought it was worth the trouble of making an internal outhaul system based on Gene Ferguson’s excellent 1997 design. Using Gene’s diagram, I ad-libbed a bit, using Harken 225 and 226 microblocks and New England V-100 1/4″ braid and sticking with wire for the 2nd block and exit out the thru-deck at the aft end of the boom to the clew.

Since the exit at the boom-end is wire, the thru-deck block is nice and small, and through the magic of the Dremel tool I’ve managed to cut a nice slot for the block. It sits in the foot channel and is just big enough to reach into the main section of the boom where the guts of the outhaul are hidden. Having a swaging tool makes working with wire a breeze – I picked up a hand tool at West Marine last year and have used it a lot more than I thought I would.

I’ll have more pictures soon – the outhaul is rigged and sitting in my cupboard with the new sail.