www.instructables.com/id/How-to-make-a-carbon-windsurf-boom/

Damn, it says I've got to wait overnight before going onto step 8.

[Edit - Here's one I prepared earlier]

All that work for a non adjustable boom to fit a rather old looking and banged up Aerotech VMG.

Also I just hope he didn't pilfer some prepreg carbon from his work that was meant to go on the wings of a 737 destined for an Australian domestic airline.

that aint prepreg, thats a dirty layup.

and that aint how i'd be doin it. WTF is all the unis??? and nothing on the bias!!!

Bertie said...

that aint prepreg, thats a dirty layup.

and that aint how i'd be doin it. WTF is all the unis??? and nothing on the bias!!!

Bertie, you seem like a real expert. The pre-preg I used is special vacuum cure stuff and only impregnated on one side. So one side of the pre-preg looks like a normal pre-preg, but the other side looks like a dry cloth. The advantage is that the pre-preg can be cured at only vacuum pressure while still getting a void free laminate with a low resin content (aerospace quality, recently qualified for Airbus).

I choose a 0-90 lay up for all the basic layers, achieved by just laminating the pre-preg (it's a weave and not UD, I preferred to apply at least 3 UD layers, but did not have them available)
So there is no +/- 45 in the basic layers. I don't think this is a problem since there will not be much torsion in the boom, the main load is bending for which a 0-90 lay up is sufficient (and more stiff).

NotWal said...

The flexible hose form work leaves the finished product looking a bit lumpy.

Still, hats off for an admirable achievement. That thin tape is something to consider.
I assume he can always modify the length for a new sail with a bit of radical surgery.

NotWal, thanks for your comment. Yes, the advantage of the flexible hose is also it's disadvantage. You can quickly form the pre-form with a simple tool, but all the irregularities will show up in the final product.
However, my intent was to make a 100% carbon boom at the lowest cost possible and fast. So I took some weaviness for granted (You don't notice this while sailing ) I worked 50 hours on this boom, which is much less than the other boom builder mentioned earlier. I reckon it took him at least 50 hours to only build the mould!

I spend only 160 euro's for the complete boom (including grip and boom head, the prepreg was for free). For a new sail I might just make another one...

Haha, seems like composites geekery runs deep in the ws'ing community. I'm 3/4 of the way through my senior thesis, which is the design and manufacture of a composite monocoque chassis for a F-SAE car. Not an easy task to undertake solo, ANSYS makes me want to tear my eyes out. Anyway male plug should be ready end of the month, almost there.

On topic thou, cool boom. Pretty cost effective, not perfect but hey gotta start somewhere.

That's right bertie wtf are all the uni's and off axis. Even if there is no torsional load you still need bias fibres to transfer load from fibres under tension to those under compression also I know several composite engineers who wont design a laminate around a woven fabric due to crimp. stiched fabrics and uni's only
Brad

Hi there guys ! This is my first post in this Forum !

I am trying to figure out how to make a carbon boom like those that i found here.
There is also a third one from Peter Ifju, but there are no information about the construction.

http://forums.windsurfingmag.com/showthread.php?t=684

@jwvi very nice construction.My problem is that i dont have a vaccum pump and my oven is big enought only for bread.You think is possible to use wet lay-up fabric ?
@Bertie it seems that you are an expert in composite. If you had a plan to make a boom which would be your approach?

p.s I have already three carbon booms , i just want to make one.