Laminating tests

[sammer]

West systems have worked pretty good for me for 7 pairs of skis.
I'm using slow hardener and making sure that everything is completely wetted out.
I would avoid using any types of filler as this will surely cause problems ( too thick to absorb into the fibers)
So far I've seen NO delams in any of my skis. A few have over 50 days now of hard riding. (read powder skis chattering over the ice. Snow this year sucked)

I've recently bought some QCM and gave the last of the west to a friend who has just started building his own skis.
He had a slight issue with not completely wetting out so ended up with dry spots as well.
(User error, he tried to stretch it a little too far, instead of mixing up another couple pumps)

My issue with west systems is its pretty darned expensive compared to QCM.

my $.02

sam

[AlexF]

When I had spoken to the technical people at west systems epoxy I had aske d them how I would know at what presure to press my ski`s. they had told me that my goal should be to have a
39 percent epoxy to fibre ratio.

39 percent?! Are you sure this is what they told you? Maybe it was 39 percent fibre?

This would mean a Fibre Volume Fraction (Vf) woould 61%.

I hope they didn't tell you this as if the technical people at West Systems told you that you should be looking to get a 61% Vf then I wouldn't refer to them as 'technical people'....'clueless idiots' would be a more accurate description.

I've managed to get verified Vfs of around 60% with some composites....

In order to get a 60% Vf I used unidirectionl prepreg tape (containing aerospace grade epoxy resin) cured in a vacuum bag within an Autoclave at extremly high pressure. And this was all done under laboratory conditions (layup in temp controlled clean room etc...).

If you speak to one of West's 'technical/clueless people' ask where their products have managed to get Vfs of 60%. I'd be interested to hear whether they admit that the don't get this fiugre or if they throw out some unverified figures/applications massaged by their marketing department.

You won't find compsoites with a Vf of 60% or above because no one would go through the cost and expense of setting up a plant/facotry capable of producing compsiites of 60% Vf and then go and use a West System Epoxy. I'm certainly not saying West Systems stuff is bad (it seems very popular for DIY sports equipment so it must have some good selling points) its just that its nowhere close to the quality/consistency of whats available (including non-aerospace stuff).

[Damon]

I could see 40% with a filler. Remember people are pressing at pretty high pressures, usually higher than typical prepreg (the stuff I work with recommends 80PSI).

Bigal - how are you confirming the % of resin in the cured laminate?

[MontuckyMadman]

well that shit was wet, transparent. Its doesn't say anything about another liquid state after the liquid to gel to hard. I guess that could have happend but where did all the epoxy go into the flash? Maybe.