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Minimum Composite Thickness/Layup

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Well-Known Member
May 28, 2010
Perth, Western Australia
I'm suprised there isn't already a thread on this, but I couldn't find one specifically. Digging around in other threads I found a few suggestions for minimums but there is obviously a degree of personal preference. Here's what I've come up with:

Glass (GRP):

Billski mensions 3×7oz UNI (3×237gsm for those metrically inclined) in one of his posts, presumably in a 0 and +/-45 alignment. Similarly my preference is for a minimum of 595gsm (~17.5oz/sqyd) Stitched Triax - which is basically the same thing! These also both compre well to a 0.6mm minimum thickness I have seen elsewhere.


There seems to be much less commentary on the minimum gauge of carbon. Autoreply mentions sandwich skins with 2×200gsm on each face, but this relates to gliders which tend to be a bit more delicate and less "moron proof". two layers of 3K 195gsm 2×2 twill is about 0.5mm thick.

Any other offers?