When mat is used you get alot of strength, however it takes more resin to "wet-out" and is thicker and harder to get to conform into corners etc. Most people cut their mat into smaller peices, i prefer to tear it with my hands. The irregular edge you get from tearing it helps it mesh in with the rest of the peices you lay on, resulting in a stronger sructure.Some of my mat i even shred up, similar to what you get using a chopper gun.
Cloth is thinner, more flexible, and takes less resin to "wet-out", but you sacrifice some strength. I cut this into larger strips, or patches.
Any more fiberglass questions, feel free to ask, ive had my share of experience.
i almost always use both cloth and mat on every project, in one way or another. i cant really say i prefer one over the other because to me they have 2 separate uses.
Example- if im making a Pepakura helmet, id use the mat first to strengthen it up and build up the recessed areas a bit, then the cloth in larger patches to cover up the rougher mat and result in a smoother, easier to work finish. (remeber mat and cloth is always placed on the INSIDE.) Then you get a really nice surface inside your helmet.
