Fixing a broken plastic bezel/frame of HP49g+

[Brad Barton]

I've tried using cyanoacrylate glues to repair the plastics on some older HP41's, but it has never worked out very well. The cyanoacrylate dries very hard, but doesn't seem to bond well with the plastic. It makes for a brittle joint, that doesn't hold up to stress very well.

I was talking about this exact subject a few other members at HHC this year. The consensus was that a better bet would be either a 2 part epoxy, or a glue similar to the Testors(tm) model glue we used to use on our models that we built when we were kids. The key I think is to find something that partially melts the plastic you are gluing, causing it to merge with the glue more fully. Once the glue cures completely, this should yield a much stronger joint.

Applying the glue neatly is a problem with all glues, especially with the type of thin plastic bezel you are attempting to repair here. If possible, I'd recommend that you remove the plastic piece completely and then re-install it once the repair is made. That way you could have better access to both the top and bottom of the surface of the part. If you concentrate the glue near the inner surface of the bezel, then you could sand it flat once the glue fully cures, and hide the sanding marks that would result. Applying the glue or epoxy with a toothpick or similar small brush should help keep you from using too much glue.

Brad