Putting rubber eye cup back in shape

[Hassasin]

Looking for some ideas how to get started on this. Have a rubber eye cup (Bronica GS1 AE finder) that's been stored in its original box for a long time, apparently placed in the box incorrectly.

Rubber looks pretty good, no visible dry rot. I'm thinking of first making a matching mould, so it can be used to give it proper shape. Warm up rubber (not sure how yet), place it on top of mould and press it lightly against it with weak yet strong enough rubber bands (or similar arrangement), then let it cool slowly, and redo the process if first attempt shows any improvement.

Any other ideas ?

 

[Rrrgcy]

Seem to remember something about boiling (or very hot) for some minute, in water and menthol or wintergreen (methyl salicylate). remove and flatten to shape (w your mold) and hold that for awhile. Rejuvenates too but it might temporarily (or permanently) minorly deform dimensions w consequent fitment issue.

 

[tom williams]

Looking for some ideas how to get started on this. Have a rubber eye cup (Bronica GS1 AE finder) that's been stored in its original box for a long time, apparently placed in the box incorrectly.

View attachment 358865

Rubber looks pretty good, no visible dry rot. I'm thinking of first making a matching mould, so it can be used to give it proper shape. Warm up rubber (not sure how yet), place it on top of mould and press it lightly against it with weak yet strong enough rubber bands (or similar arrangement), then let it cool slowly, and redo the process if first attempt shows any improvement.

Any other ideas ?

Hassasin, here's an idea, using a bit of modeling clay, some moldable rubber paste or pourable latex, and a bicycle patch + glue. If you can apply your eyecup to the modeling clay to get a decent impression, you can then modify the impression where the damaged part of the eyecup fell to create an unflawed negative mold. Trim the edges of the damaged part of the eyecup, then put the eyecup back onto the mold. Fill the damaged part of the eyecup area with latex, smooth it out and let it cure. Then apply a bicycle inner tube patch over the repair, overlapping the adjacent undamaged parts of the eyecup. Use the glue supplied with the inner tube patch.

 

[Hassasin]

Hassasin, here's an idea, using a bit of modeling clay, some moldable rubber paste or pourable latex, and a bicycle patch + glue. If you can apply your eyecup to the modeling clay to get a decent impression, you can then modify the impression where the damaged part of the eyecup fell to create an unflawed negative mold. Trim the edges of the damaged part of the eyecup, then put the eyecup back onto the mold. Fill the damaged part of the eyecup area with latex, smooth it out and let it cure. Then apply a bicycle inner tube patch over the repair, overlapping the adjacent undamaged parts of the eyecup. Use the glue supplied with the inner tube patch.

Thanks for the idea. At this point there is actually no damage to the eye cup, only deformation (rolled over bottom part as in photo), so my plan is to try soften it and shape back into form again. How successful that can be, I have no idea.

 

[Truzi]

There is something for automotive use that supposedly "rejuvenates" rubber seals, though I've not tried it. ATP's (company) AT-205. Rejuvenate may just mean soften or swell. It's supposed to be similar to claimed effects of wintergreen or menthol oil.

I'm not sure if you want it on your eye cup. It also may not work for your situation, though it's possible it could help you reform it.

 

[Hassasin]

There is something for automotive use that supposedly "rejuvenates" rubber seals, though I've not tried it. ATP's (company) AT-205. Rejuvenate may just mean soften or swell. It's supposed to be similar to claimed effects of wintergreen or menthol oil.

I'm not sure if you want it on your eye cup. It also may not work for your situation, though it's possible it could help you reform it.

I'll look that up. I have another eye cup that is basically trash, but same rubber, so good for some testing.