Exploding carbon armadillo.

You may remember that some time back we produced a single skin carbon hull of 3 layers of 16g/m2 tissue for Armadillo. All seemed well - very light and reasonably stiff.

My mate Jeff is much better than I am at getting a good surface finish so I asked him to do it. Thngs got delayed (as usual) and he only got round to it the other day. In the course of his efforts he tapped the hull sharply but not very hardon the table to get the dust off and it shattered into 5 pieces!

I know carbon is brittle, but this is ridiculous. The resin used was WEST and the layup was, if anything, resin rich.

Any comments?

I’m sorry for your loss. :frowning:

I have some worries about my balsa but shattering isn’t one of them. My guess is that the resin contracted as it cured and introduced tension into the hull. reminds me of tempered glass or ceramics. We once had a ceramic bowl, CorningWare, simply pop into 5 pieces after pushing it aside. No immediate impact, just a grapefruit skin left in it.

Clearly the power of the pentogram is at play here, I believe you may be on a lay line Angus but tallastro’s event is more difficult to explain.

Bang… bang… bang… that’s the sound of me hitting one of my hulls against the wall… nope it’s ok. You must get into these cold molded foam laminates Angus :sly:

Seriously though that is a shame because we needed to find out how the Armadillo performed. Will you try a glass version next…? Is it possible the epoxy was mixed differently and so more brittle than intended… shattering is usually more a polyester thing isn’t it?

yo ho

Angus -

I have never known WEST to become brittle - usually most complain of it’s softness. While I have not experimented with all various versions and mixture combinations, it sure would serve a good purpose if you dropped an email to Gougeon’s technical department. They might like to see a sample of left-over hull, but since it is “their” stuff, my guess is that you will get an excellent technical response - the same as if your 40 foot off-shore racer just had it’s carbon hull crack. Give them a technical question to mull over and let us know how they responded. Direct letter to J.R. Watson as a starter, although they have a new batch of “techies” working their now as well.

Unbelievable!! I haven’t worked with carbon yet, but my experience with West products on glass and kevlar hasn’t come close to the kind of brittle result you mentioned. Dropping a glass hull on the concrete floor of my workshop (chine hulls are easier to hold on to!) has resulted in the occasional hairline crack easily repaired with some ACC.

Maybe a new name for the boat…Humpty Dumpty??

I know an epoxy manufacturer nearby who has given me some of his stuff to try to steal me away from West products. He seems to know his business well. If you’d like, Angus, I could put you in touch with him.

Bill H

Bill - it was a malign fate. I called the design Armadillo because it looked like one up side down as a half-planked plug.

Normally I call designs somethging canine - that means I got it in first when someone tells me its a dog!