Reinforcement types information

General Composites Discussions Products Talk
#1

Ok, I’m going to take the time to post the different types of composites reinforcements here and sticky it. This will take some time and if anyone wnats to chip in, please do. Please ask any questions on the materials in a new thread, thank you.

Fiberglass:

Surfacing Veil Very thin, angel hair, chop strand material for the first layer after the gel coat to eliminate cloth print thru, to allow you to lay this layer up and wait until the next day to start the reinforcements layers. I also use it for spray booth filter pre-filter screening too! .010 or .020 thickness only. Not for use with Epoxies.

CSM Chop Strand Mat, the cheapest material, it is held together with a styrene binding agent which melts out with the use of PER, Epoxy is not used with this material, rated in OZ. per Square “Foot” (since the glass makers make this material, they rate it in weight per square foot), like 3/4 oz, 1 oz., 1 1/2 oz, 2 oz and 3 oz.

CSM Continous Strand Mat, long strand version of the chop strand type, the next cheapest material, it is held together with a styrene binding agent which melts out with the use of PER, Epoxy is not used with this material, rated in OZ. per Square “Foot” (since the glass makers make this material, they rate it in weight per square foot),like 3/4 oz, 1 oz., 1 1/2 oz, 2 oz and 3 oz.

Unidirectional The Fiberglass only runs in the 0 degree direction and with a felt backing that it is sewn too to keep it together.

Cloth Woven This is a bi-axis, only 2 directions Warp (length of the material coming off the roll, 0 degree) and Weft (width wise, 90 degree) woven fiberglass like the cloth item you are wearing, rated in OZ. per Square “YARD” (since this material is woven by textile companies, they rate it the same way as reg. cloth), can be thin as 3/4 oz to 20 oz tooling cloth.
There are several versions of this FG cloth like E-Glass (Econo fiberglass and flat strands) to a stronger S-Glass (a Trademark of Owens-Corning Fiberglass company) which has the strands twisted for more strength and better wicking of the resin into it too.

Woven Roving Just like the above cloth but tons heavier strands, does not bend easy, for mostly flat surfaces…

Aramid
[SIZE=2]Another name for Aramid, “Kevlar” made by DuPont. Usually bi-direction axis. Very hard to cut except with special hand shears or specialty tools. Tightly woven DRY Kevlar used for ballistic body armor protection to more open weave for better hold together than Carbon fiber (when a race car gets crash, the CF will expode into many peices but if there’s Kevlar in the laminate, then it will stay together more). Better to use Epoxy resin but you can also use PER too!

[i][b][SIZE=4]Carbon Fiber[SIZE=2]
TBC…

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#2

Might be worth adding that powder bound CSM can be used with epoxy resin systems, and that surfacing veil provides a nicer final finish, if used as the last layer in a hand lay up.

#3

Cloth Stitched: Tows that are laid flat at any angles (0/90, 0/90/90/0, 0/-45/90/+45, etc) and then stitched with cotton/polyester, etc…

#4

so what’s the significance difference between continous & chopped strand mat???

are there length limitations/boundary between both of them???

#5

Chopped strand mat is made of randomly placed short fibers. It’s pretty much transversely isotropic but has relatively poor strength characteristics compared to continuous fibers composites pulled in their fiber directions.

Continuous fiber composites though are weak when pulled perpendicular to the fiber direction. I don’t think theres any length limitations although if you mean fiber length there is a such thing as critical length where a fiber is no longer stressed and becomes ineffective in a composite.

#6

They are generally classified as Biaxial(0/90 degree), Double Bias(+/-45 degree), Triaxial(0/+45/-45 degree or +45/90/-45 degree), Quadraxial(0/+45/90/-45 degree). All of these can be with or without CSM backing.

#7

Some weavers also designate +45/-45 as being a Biaxial, which some know as being +90/-90. Always refer to the figures not just the terminology. You can also ask the weaver to design a weave to suit your application. You may need to have as an example +30/-30, but this will only be done if you require a reasonable volume of product, the width of the fabric can also be varied.

#8

Apologies I meant to write 0/90 not +90/-90.

#9

Sizing is a surface treatment applyed to the fabric so that improves the bonding to an especific resin.

Carbon is mainly used with epoxy resin, and that´s why most carbón makers select a sizing for that resin. If you´ll use other resin like PER or VE, the adherence would be not the best, so if you will use VE or PER resin for your carbón laminate, you must better look for a carbón maker or trade which uses sizing for such resin. Always in order to get the best adherence. If the adherence is not critical as for cosmetic parts, you may use whatever sizing…

Glass has diferent sizings as a good uni or biax glass may be used with epoxy, or a CSM is usualy impregnated with PE. So, special attention to sizing for your glass laminates…

Kevlar is always a pain. Unsharps every tool as scissors, drills or saws, bad to impregnate and once cut, leaves a bad finish horrible (imposible ?) to make beautiful. Very good for impacts, balistics, helmets, etc, as polyethilene or other termoplastics

#10

Very Informative…