Fiberglass instead of sheet metal?? pros/cons??

just bog it up (bondo= bog) paint it red, sell it to someone who thinks he has found the car of his dreams


a few months later he finds some small bubbles on the door bottoms.

he brings it to me and says- "cant be much to fix it right?"







because the water has no were to go the door frame rusts away-



So I have to re do it -





I think I will use metal--



after its welded in, paint the inside with POR15 rust encapsulating paint, a small amount of bondo, prep and paint. good to go.

 

Anybody can go down to Harbor Freight, buy a wirefeed and be an expert welder. Anyone can go to the hardware store and buy fiberglass and repair a floor. Right, yeah. And if you are too cheap to weld you can just braze it, lol.

I am NOT going to recommend fiberglass for repairing rust out holes in outer body panels because of cosmetic issues, although it CAN be done, and last for as many years as the car, from a structural standpoint.

Most of the posters flaming against fiberglass are doing it from a) ignorance, or b) superior metalworking skills. I dont respect the idiots (whose ignorance is gospel), I recoginze some have only seen incompentent fiberglass work (if it was compentent they would not have seen it). I do respect the people with superior skills, however keep in mind that a person expert in fiberglass may well be able to do a project better engineered and in less time than they could do the same project in steel. At the same time the expert metal worker would be able to do the job quicker and better than they could conceve of in fiberglass. To each his own.

As to strength of fiberglass vs steel, they are different. One is not necessarily better than the other, it depends on the thickness, weight, shape, and application. While 18 ga steel may be stronger than the same thickness of fiberglass, a pound of fiberglass may be stronger than a pound of 18 gauge (and a lot thicker of course).

Dont take this post personal... but to take the time to allow each to do with THEIR car what they want, otherwise risk others (including the government DICTATING) not allowing you do do with your car what you want.

 

Karl, given your name and location, I assume you are quite familiar with methods of reinforcing fiberglass. I've used your fenders in the past, nice stuff!

 

I repaired the rust through on the lower part of the doors on a 46 Chevy truck with the POR-15 and their mat material. I did not like to do it but that is the way the owner ask for it to be done.
Three years the truck was involved in a side impact accident and the vehicle was brought back to me for repairs. I was amazed at what I observed. All the mat was still firmly attached to the metal and was actually deformed just like the surrounding metal. The only issue I observed was that in several places where it deformed bast its breaking point is actually broke and metal would likely not have done that.
Made me re thank some of my pin hole repairs.
Scott...