Wednesday, May 27, 2009

An ounce of prevention..

There's been some chatter on our calcup yahoo groups lately about reinforcing the front end of your formula boom head. Call it preventative maintenance or just plain common sense. The result gives you a bit more confidence in your gear- giving you the opportunity to push harder + prevents the opportunity for catastrophic failure. A lot of racing has to do with preparation before the race even begins.
To top it off, the cost of replacing a broken boom with a new one is about 10x the cost of the repair. Finally, any chance you have to upgrade to the Maui Sails head will be well worth it. The Streamlined head is still way better than the stock heads but comes with its own set of issues. No sitings yet of North's new ifront boom end but it looks like it wont work on a beefed up boom.

Several California sailors have put there 2 cents in at the same time I was about to embark on my latest carbon endeavor. Thanks to Soheil, Joe Roth and Royce for contributing to this instructional guide to reinforcing a formula boom head.

What you'll need: 2 part epoxy, electrical tape,(peel ply- optional), bi directional carbon, plastic mixing bowl, plastic gloves, foam brush and squeegee.
1. Begin by taking off the existing boom head.

2. Remove the boom grip for about 2 inches back from the front (gives you more area to wrap and beef up). Use a rough file.

3. Sand exposed carbon boom arms to rough them up and also to remove any grip glue in the area you will be wrapping.4. Next comes the Carbon prep.
Cut a strip of carbon about 3-6 inches wide and long enough to wrap continuously from one side to the other (grip to grip) with some overlap.

5. Do a dry test wrap with this strip to get a feel for how you will be wrapping, and to make sure you'll have enough carbon for full coverage.

6. Put on some gloves (more than 1) and do the rest of the steps in the garage and/or over some plastic and paper where dripping epoxy resin won't upset your wife or girlfriend or landlord!

7. Mix your 2 part epoxy resin well. I used West Systems regular curing speed (not the slow cure stuff...), that you can get at West Marine.
Incidentally, I bought my carbon cloth at Tap Plastics.

8. Use a brush to coat the to-be-wrapped areas of the boom with a thin layer of epoxy.

8.1 If you have a long, 6' or so, flat surface on which you can lay out the 3" to 6" wide cut strips of carbon over a piece of plastic or a couple of layers of wax paper.
Then pour some epoxy over the carbon strips and using a small plastic epoxy squeegee or foam brush and completely wet out the tape and squeegee off the excess.
Next roll up the wet carbon strips onto a cardboard roll (covered with packing tape so that the epoxy doesnt soak into cardboard)

9. Unwrap your cloth tightly around the boom from the tube you wrapped it on, ensuring that it wets out with epoxy as you go. Use your wet brush to add epoxy to any dry areas. This is a messy job-especially with the loose ends of carbon, but use preseverance and work quickly to avoid the epoxy from hardening too much.
10. Once you've gone grip to grip with your carbon wrap, use some peel ply cloth and/or electrical tape to TIGHTLY wrap over your wet carbon wrap job. This will squeeze out excess resin and cause your carbon to adhere firmly to the boom head without any voids. This is called the poor man's vacuum bag.

11. Let the whole thing cure overnight, and then unwrap the electrical tape/peel ply bandages. These don't stick to the cured epoxy, and should peel off fairly easily.

12. You might want to sand down any rough spots so that your boom
won't cut your hands during normal handling.

13. Now, your old boom head will not fit because your boom arms are
fatter where you wrapped them, so you will have to either retrofit an
aftermarket head meant for fatter booms, or somehow modify the
bushings from your old head to make them thinner. Depending on which
boom head you have, the manufacturer might have thinner bushing
available (Streamlined and Maui Sails boom heads have 2 or more
bushing thicknesses available). You might still have to sand or shim
these in order to get your boom head to fit as your wrap job is custom
and not any particular known thickness.
The result of all this is adding a few years onto your carbon boom.
Im pushing my 5th season with a blue HPL boom I reinforced several years ago.

*This great tip was sent to me by Anders Petersson- who knows a thing or 2 about carbon endevours:. Great stuff, but I would add one final step. You should protect the reinforced boom head with a clear coat of polyurethane. Most brands of epoxy are unstable to UV radiation and will eventually break down if exposed to sun light. An added benefit is that the clear coating makes the carbon look much nicer.-


Shawn Davis said...

Steve, this is a great how-to article. Did you see the "out of the box" article in the most recent Windsurfing Magazine about the new North boom head? It sounds like their research has shown that stiff boom heads are slow when it gets windy. So is the answer to have stiff boom arms with a softer boom head?

USA-4 Steve Bodner said...

I didnt see the article but the north option looks like it would give you the most options for different wind conditions unfortunately it doesnt look like it would fit on a enlarged diameter boom like the Maui Sails front end or streamlined head.
Having the best boom head in the world doenst make much of a difference if your boom arms crack at the front!

Jaco said...

Dear Steve,

Sorry, this has nothing to do with the nice boom article.

But I was wondering if you have some more trim info of a north warp 2005 11m. I am just starting with some formula windsurfing and I want to begin with one of the Regio cups here in Holland. I read in one of your earlier articles that you sailed this sail before.

So I hope you have any old info, trim sheets, tips, ideas,etc.

I sail the Starboard 158, in combination with a Deboichet R13 70 H fin and the proper Northsails mast.

Hope you can help me out.

Good luck with racing this evening and tomorrow.


USA-4 Steve Bodner said...

I know that sail has a lot of range.
Dont be afraid to try a few different downhaul settings till you find the fastest setting. Once there it shouldnt change more than 1-1.5cm between light and medium wind.
The outhaul is the real key to fine tuning the sail. You can get a lot of shape by bagging it out yet still sail overpowered with it flat.
As I recall, the batten under the boom had a tenancy to break. You can prevent this by reinforcing the joint where the front tube and carbon rod join together. Wrap the joint with s small strip of glass or carbon and epoxy and use the poor mans vacuum as mentioned above.
Good Luck

bry said...

Don't forget that np makes some excellent booms!