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Laser-Cut Booms

Most people who make their own wooden mast also choose to make their own booms. Normally you would make them out of spruce and simply mill them to correct dimensions. Some decide to also laminate their booms from two or three individual layers that they’ve milled down on the table saw.

In my case, because I have access to a laser cutter and can play around a bit, I decided to make my own “artsy-techno-structural-funky-scifi-ishy” booms out of 1/32” plywood. I ended up with a really funky set of booms, but I like them. Contact me if you want the same booms, but if not, then use your own creativity and imagination to come up with your own design. There are several businesses that will happily laser cut the parts for you.

For my latest main boom, we used National Balsa because the laser cutter that I have access to is down. They cut two sheets of plywood for me using my own designs, and they charged $65 (USD, 2018) including materials and shipping. It’s a bit spendy, but if you can swing it then it lends a funky accent to an otherwise very traditional design.

Here is how I made the booms.

Once the laser cut parts arrived from National Balsa, I gently sanded the burn and scorch marks off.

Then I prepared two pieces of scrap ¾” MDF leftover from our strongback. If you don’t have any scraps, then you can also simply disassemble the strongback and use the sides. I made sure that the MDF pieces we used were very flat, and that the edge of one of them was perfectly straight. Trim them on the table saw if needed. The idea is that the boom will be held flat between these two pieces when curing. The bottom piece will be flat on the table, while the second piece will be on edge to put even pressure on the whole boom.

I then put plastic packing tape on the flat side of the bottom piece, and along the edge of the top piece.

Then take the bottom piece to the drill press. The drill press should be able to drill a perfectly perpendicular hole. Drill three holes in the bottom piece. I used a 1/8” hole. The idea is that you will insert three pieces of 1/8” dowel to act as alignment poles. Put two at the back end where the end of the boom pieces will meet. One pole is for the very end to align to, and the other is for the top to align to. Then drill a third hole near the other end that the top will align to.

Once your MDF pieces are ready, then mix up some epoxy (two marks on our syringes).

Apply the epoxy to the laminations. I found that it was quicker and easier to simply dip my gloved fingers in the epoxy and rub it onto the plywood. It gave a more even and thinner coat of epoxy. You don’t want excess epoxy because it will fill the open spaces and corners and will look unsightly. Just use your hands.

Neatly stack the laminations one-by-one, in proper order, onto the flat piece of MDF. Use the alignment pins to keep them perfectly straight to each other.

When done, eyeball the assembly for excess epoxy. Then carefully set the top piece of MDF onto the top of the laminations. Carefully press down being sure to only press “down” and to not shift the pieces. Inspect the entire assembly and make any adjustments. How's it look?

Let cure. VoilĂ !

This main boom is 23" long and weighs only 1.3 oz. (37 grams).

And here is what a similar but shorter main boom looks like on the Sun Wind HF that was finished last November.



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