Determining cloth in layup

[quicksail]

We have a project and we need to find out what fibers/clothweight was used in a layup. We only have a sample piece of the epoxy/glass layup. If it were polyester resin we could just burn the resin off and look at the fibers. The question is can we do the same for epoxy? I know there are some flame retardent epoxies so I am not sure how I will be able to find what the layup was.

Any help would be appreciated.

[Herman]

You can burn the epoxy off as well. Just a bit smelly... Don't inhale the fumes.

Basicly they are all hydrocarbon resins, so above a certain temperature, the C-H bindings fall apart.

[Landlubber]

Weight the sample accurately before amd after the burn of course.

It is an accyrate method to determine glass/resin ratios

[Herman]

I presumed he'd knew that, as he is already using the same method with polyester.

As for fire retardant epoxy: You are more likely to stumble upon fire retardant polyester. When burnt off, it will leave white powder. shake that off before weighing.

[Knut Sand]

Also, measure the thickness....
If it's flame retardent, it will burn... evenually, just takes more time, and if it's a good flame retardent, it will not keep the fire by it self, until the inhibitor have burned away, so you will have to have the gas flame there to keep it burning.... just don't give full throttle at the gas flame, as this can cause the fibres to blow away, better take it easy for best possible result.