Re: [Cameramakers] Re: Bellows making (Urethane!)
Robert Mueller wrote: I do not know whether I have access to anything similar to the "PL" Roof and Flashing Sealant but I doubt if I would use it even if I could buy it unless I received a pretty secure guarantee of a long lifetime. Urethane foam is one of the worst materials which have ever been introduced into cameras. This is the stuff which changes into mud after cameras exceed a certain age. Removing and replacing this junk is a terrible task and I am sure many otherwise fine cameras have landed in the scrap heap on account of the costs it causes to have a repairman spend much time cleaning up the camera before replacing the foam. A fantastic initial bond followed by self destruction after a decade or so is no solution in a case where only a moderate strength bond is needed, though for at least my remaining life on earth (estimated at 20 to 30 years!) Perhaps the problem has been solved in modern urethane, but I have never heard anybody admit there has ever been a problem so I don't expect any assurance it will never happen again. Until you have that assurance, consider the sinking feeling when you find your work reduced to a paste impregnated bag by decay of the cement. Bob Dr. Robert Mueller Institut fr Festkrperforschung, FZ-Juelich D-52425 Juelich, Germany phone: + 49 2461 61 4550 FAX: + 49 2461 61 2610 email: [EMAIL PROTECTED] ___ The urethane sealant is not a foam but a solid rubber. Makes an adhesive seal as opposed to the occlusive non-adhesive seal of silicone. Same stuff is used in industry to seal expansion joints in concrete walls and to seal cracks in pavement so I would guess people have faith in its durability. Seems like it ought to be good for sealing cameras. Erben ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Re: Bellows making (Urethane!)
The urethane sealant is not a foam but a solid rubber. Makes an adhesive seal as opposed to the occlusive non-adhesive seal of silicone. Same stuff is used in industry to seal expansion joints in concrete walls and to seal cracks in pavement so I would guess people have faith in its durability. Seems like it ought to be good for sealing cameras. I've used it to seal pinholes in an enlarger bellows with good results. Don Feinberg [EMAIL PROTECTED] ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
[Cameramakers] Re: Bellows making (Urethane!)
I do not know whether I have access to anything similar to the "PL" Roof and Flashing Sealant but I doubt if I would use it even if I could buy it unless I received a pretty secure guarantee of a long lifetime. Urethane foam is one of the worst materials which have ever been introduced into cameras. This is the stuff which changes into mud after cameras exceed a certain age. Removing and replacing this junk is a terrible task and I am sure many otherwise fine cameras have landed in the scrap heap on account of the costs it causes to have a repairman spend much time cleaning up the camera before replacing the foam. A fantastic initial bond followed by self destruction after a decade or so is no solution in a case where only a moderate strength bond is needed, though for at least my remaining life on earth (estimated at 20 to 30 years!) Perhaps the problem has been solved in modern urethane, but I have never heard anybody admit there has ever been a problem so I don't expect any assurance it will never happen again. Until you have that assurance, consider the sinking feeling when you find your work reduced to a paste impregnated bag by decay of the cement. Bob Dr. Robert Mueller Institut fr Festkrperforschung, FZ-Juelich D-52425 Juelich, Germany phone: + 49 2461 61 4550 FAX: + 49 2461 61 2610 email: [EMAIL PROTECTED] ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
