Do you have a project in mind but have no idea where to start?  Let us help you.  One of the first things you will want to do is decide what kind of fiberglass you want to use.  Do you need to build up thickness fast?  Are you concerned about strength? Do you have tight corners you are working with?  Let us break things down a bit to help you decide if fiberglass cloth is right for your project or if you are needing chopped strand mat. Keep in mind that you can actually use both together to achieve your desired outcome. Below is an overview.

Fiberglass Cloth

(Plain weave fiberglass cloth)

Fiberglass Cloth is a woven fabric. Plain, 4 harness satin and 8 harness satin are the weave styles we carry. The 46 and 10 ounce plain weave fabrics are the most commonly used. In this simple plain weave pattern, warp and fill yarns are interlaced over and under each other in alternating fashion. The plain weave is the easiest to handle since it does not unravel as much as the other weaves when cut.

In the four-harness satin weave pattern there is a three by one interfacing where a filling yarn floats over three warp yarns and under one.

The eight harness satin is similar to the four harness satin except that one filling yarn floats over seven warp yarns and under one. The satin weaves are slightly stronger and more pliable than the plain weave and are easier to conform to curved surfaces. They are more difficult to handle than the plain weave, though. Use fiberglass cloth when you are looking to create a strong, light weight product.

Chopped Strand Mat

Chopped Strand Mat (also known as fiberglass mat) has short strands of fibers held together with a resin binder. The fibers are randomly oriented. Mat is only compatible with polyester and vinyl ester resin. When resin is added to the mat, the binder dissolves and the fibers can be moved around. It is easier to conform mat to tight curves and corners than it is with weaved fabric. The reason chopped strand mat is not compatible with epoxy resin is because the binder holding the fibers together needs styrene to properly dissolve.  Polyester and vinyl ester resins have styrene in them. (There are some places that sell chopped strand mat that is compatible with epoxy but it is hard to come by and much more expensive). Chopped strand mat is the least expensive fiberglass and is often used in mold construction or projects where thickness is needed. Mat is often used as the first layer (before the gelcoat) in a laminate to prevent print through. Print through is when the fabric weave texture shows through the resin. Chopped Strand mat does not have much strength. If you need strength you should choose a woven cloth or you could mix the two. Mat can be used between layers of woven fabric to help build thickness quickly and aid in all layers bonding well together.

If you have any questions feel free to comment.  We will do our best to reply with an answer. Or, you can visit our website Fiberglass Warehouse for more information.

For more detailed information on each fiberglass cloth we carry, you can CLICK HERE.


By Dallin Leach 50 comment


comments (50)

  • Fiberglass Warehouse

    @Malcolm- Either woven roving or chopped strand mat would work. You could even use 1708 knit fiberglass fabric as well.

  • Malcolm


    I need to glass fibre a wooden mast step in my boat. Should I use woven or cut strand?

  • Fiberglass Warehouse

    @Jeff- regarding your questions on the soft spots in the floor of your fiberglass bay boat. You are going to want to replace the wood underneath, first. Then you can use mat over top, or a combination of both fiberglass mat and fiberglass cloth over top the new wood. I hope that helps!

  • David j Tillema

    Can I use Fiberglass matting and do infusion? if so , what resin is recommended?

  • Robert Otto

    Good day folks, I have a 6ft * 5ft cedar hot tub that ive built out of 2*4’s. Its 36" deep. I love it and so does my family but I dont love the leaks ;) ive put countless tubes of clear silicone into it with no real résolution. Ive recently come to the idea of fiberglassing the entire interior. Would you be so kind as to recommend the most appropriate products to complète this task.

    Thank you for your help with this. I am out of my élément here!


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