I recently scored an inexpensive esterbrook safari with one of the original style plastic caps. As I understand is very common with these pens (because the plastic is pretty thin and cheap) its got a couple hairline cracks on the cap lip. My initial thought is to try to stabilize the cracks with some solvent welding. I've spent the past few days scouring the internet including posts in this sub-forum but haven't been able to directly confirm what type of plastic is used in these pens. Is it celluloid like they used to construct the J-series models or perhaps a different type? Any expertise on this matter anyone could share would be greatly appreciated.