I'm looking for an acid that can solve a polyester, fiberglass composite. However it cannot damage steel.
First of all i like to say that i'm not a chemist. I work in a plastic moulding company. Let me sketch a background. We make bars out of a polyester strengthened by fiberglas. To make this we have the two materials beeing pulled through a heated steel pipe (the mould). The polyester melts around the fiberglass and forms a strong lightweight pole. However sometimes the pole breaks mid process and then there is a part that's stuck in the mould. Like in the picture
It's very hard to remove the polyester/fiberglass bar from the mould, dare I say near impossible.
I was wondering if there is an acid that solves the polyester but makes no damage at all to the chrome steel mould.