I've not used fiberglass on a car or truck BUT I have worked extensively with composites of all kinds for nearly 30 years. Fiberglass is not made for that type of application. Can it be used to patch metal? Probably (if the bonding agent POR15, resin, etc. will stick to metal). All the glass fibers do is lend strength to the resin. The resin by itself has no strength, compressive, tensile or shear. If the resin holds the patch will most likely hold, at least for a while. I've not used POR15 so I don't know it's characteristics. If it gets hard like polyester or epoxy resin it may be suitable for using with glass fiber. If it stays flexible it's NOT in any way suitable for any sheet metal patch. Using glass to patch metal panels is considered Arkansas engineering at it best. The downside of using any composite in any application is that while it has major strength to weight benefits, when it fails it totally fails. Metal will deform and can be straightened and will maintain most of it's strength. Once a composite is stressed to the point of failure it looses ALL strength and must be replaced.
Last edited by Tiny; 07/23/2010 10:59 PM.
