Dark Helmet: Begin the Fiberglassing

Because of its strength and the ease with which it can be formed, I chose fiberglass as the medium for the helmet shell.  I have worked with fiberglass in the past, but only as a tool to repair an existing structure.  I’ve never tried to fabricate with it.  So, I had a pretty good grip on the basics, but not a lot of practical knowledge.  That in mind, I decided to try some small-scale tests:

On the left, I had some plaster that had hardened inside a water bottle.  I covered it with polyurethane and using that as a test plug, I went ahead and wrapped the fiberglass around it.  The right side is a water bottle that I wrapped in fiberglass with no prep. When it all dried, the fiberglass was pretty well stuck to the plaster plug as well as to the bottle.  I expected the bottle’s results, but the plaster was disappointing.

New game plan was to cover the plug in many layers of poly and then wax it heavily, so that was the next step.

Once the plug was sealed and waxed, I started putting layers of fiberglass on.  I would let a layer dry and then put on another until there were at least 4 layers across the whole helmet.  Once that dried and cured, I attempted to pull the helmet from the plug.

That’s the plug after the shell was removed.  Total disaster.  The fiberglass didn’t want to release, even with the sealer and the wax so I was stuck using a hammer and chisel to break up the plaster and the foam and dig it out of the shell.