CSM - Chopped Strand Mat - is made of glass, chopped into lengths about 50mm long and mixed at a random pattern.
Common Sizes of CSM are shown below, but other weights are manufactured. The CSM is most commonly 1040 mm wide in roll form and cut to length.
300 CSM - weighs 300gram per square meter.
450 CSM - weighs 450gram per square meter.
600 CSM - weighs 600gram per square meter.
CSM usually requires up to about 2.25 times its own weight in the amount of resin required to saturate the mat. i.e. A square meter of 450 CSM will need about 1.01 kg of resin. For calculating how much is needed to do a job, the a rule of thumb would be:1 kg of resin for every 1 sq.mtr. of 450 CSM per layer of CSM. (obviously, the other weight mats will require a different amount of resin - so simply multiply the CSM weight by a factor of 2.25 to obtain the resin required). 450 CSM (rolled with a compression roller when wet) is approximately 1 mm thick when cured. 600 CSM is approximately 1.5 mm thick.
WOVEN CLOTH - this cloth comes in various weights, widths and construction. Most common type of woven cloth is plain weave, and most common of the plain weave is 200 gram weight per square meter. The same 200 gram material is available in tape form of various widths. Almost as common is 98 gram cloth. Woven cloth is extremely popular as it uses about its own weight in resin or about half the amount of resin as with CSM, So 200 gram plain weave will only need about 200 grams of resin. It is also suitable for epoxy resin.
Other Cloths . . .
Q. I am trying to build an esky to fit into my truck. I have panels of extruded polystyrene insulation and I want to cover the outside and inside with cloth and resin. What cloth should I use and what resin should I use?
A. Use a 5:1 epoxy with 198 gram woven cloth, maybe 2 layers wet on wet. Woven cloth uses about its own weight in resin, so 198 gram plain weave will only need about 198 grams of resin / mt.
Q. What can I use to build bike parts from? Would you suggest a mix of chopped matt for build up with carbon and fibre cloth for strength and beauty over the chopped mat
A. Carbon and then backed up with double bias
Q. What would be your recommendation on the fiberglass used under or in between paint to bond/strengthen metal - Tissue or Fibreglass Chopped Strand Mat?
A. most people use simply CSM with success
Q. Can CSM be used to patch a hole in metal and if so what sort of resin would I use with it?
A. yes it can and most people use polyester resin
Q. I have a gal water tank that has pin holes on bottom and I want to fibreglass the bottom of tank - it is 900 mm round. Which of your products would be best suited?
A. Use polyester resin with 2 layers of 300 gram chopped strand mat. 300gm CSM will use about 1.3 kg of resin per sq mtr