Bondo is a polyester body filler, it is used on cars mostly, but can be used for anything! Its basically like resin but in a mixable putty form. It helps fill in all those problem areas! There should be some threads on here about it.
mr donnelly i am agreeing with rheiner
but your fiberglassing went wrong. you were supposed to have sheets that you apply the resin onto and stick INSIDE the helm
then you resin the outside, sand it and then add bondo to fill up the gaps, add a layer of primer and then paint.
other than that, GREAT JOB MAN