Binoviewer adhesive question

Has anyone experienced a prisim or mirror inside a binoviewer fall free inside?
If so, how old were they?
Was there any indication that the adhesive used was not correct for the application and may have degraded causing this problem?
Does anyone have any experience with the proper adhesive to use for this application?
Thank You

I assume you are talking about a generic Chinese binoviewer if you have adnesive mouinted prisms. I think you will need screw down mounts that can be collimated instead of adhesive mounts in any quality binoviewer.

Harry Siebert told me that he has fixed quite a few cheap Chinese generic binoviewers and strengthened the prism mounts. You might want to contact him at Siebert Optics.

I solved my Chinese binoviewer problems by getting one of his Black Night BN22 binoviewers. Nearly 3 years since buying and it's still collimated adquately. It's also lighter than the Chinese binoviewer, besides being stronger and a better optical performer.

Baader made upgrades to the prism mounts in their Maxbright version of the generic Chinese binoviewer. The Siebert binoviewer looks like a BW Optic binoviewer to me, and a lot like the Lumicon binoviewer as well.

Phil