# Roving VS non-woven Biax

Discussion in 'Fiberglass and Composite Boat Building' started by Roy Berntsen, Aug 17, 2016.

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### Roy BerntsenRoy Berntsen Design

I wonder if there is a conversion rate to get from a roving to multiaxial stiched-biax in terms of weight or thickness.

I have calculated scantlings for roving but want to use AMT. AMT should give similar properties with less weight/thickness

Thanks for any help on this.

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Doctorx, I suspect that thickness will be a major stiffness determinant without serious regard to the material in the space between the most remote fibers.

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### Roy BerntsenRoy Berntsen Design

Well this is a sandwich configuration, so not so much. I was thinking non-woven had better mechanical properties than woven roving, but if they both are made of e-glass they would probably be similar in tensile/compression/stretch properties... How ever in a laminate non-woven would perform better due to no over under weave structure?

But I guess I can compare:
Roving, 814g/m2 = 1,05 mm
biax 0/90, 816g/m2 = 1,06 mm

Roving 610g/m2 = 0,79 mm
biax 0/90 612g/m2 = 0,79

This tells us that roving and amt fibers has the same thickness for same weight. This meens we have to look at the mechanical properties to see what can be obtained with non-woven vs roving.

I need to get some datasheets and see. Anyways the polyester will probably be the weakest point in the sandwich so maybe this is just a waist of time...?

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### Mr EfficiencySenior Member

Woven is much cheaper, a shame to use with an expensive core though. Fibres are not straight, so loses strength that way. More suited to single skin glass.

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