Liquid electrical tape for bellows repair

[rdeloe]

A camera I just bought came with replacement synthetic bellows. The bellows themselves are brand new. There are no pinholes, and no light leaks in the body of the bellows; they're in excellent condition. But, whoever installed the new synthetic bellows to the old frame was sloppy. Where the bellows are glued to the frame I'm noticing a small amount of light leakage.*

A new bellows for this camera from the manufacturer would cost more than the camera is worth, so that's not an option. I wonder if a very small amount of "Liquid Electrical Tape" applied to the edges of the bad glue joins might due the trick. The product I'm thinking of is called "Permatex Liquid Electrical Tape". The manufacturer's description says "Applies as a liquid, then cures to a flexible, vinyl polymer". Has anyone used this kind of product to deal with a problem like this?

Thanks, Rob

* I discovered the leakage by installing a light fixture in a lens board and sticking it into the fully extended bellows (with an LED "bulb" equivalent to a 60W incandescent, but giving off very little heat). I set the camera up in a light tight room, turned off the lights, let my eyes adapt for 5 minutes, and then turned on the light fixture inside the camera. After a while I noticed the tiny light leaks at the joins.

[Pere Casals]

4 bellows

You need any adhesive that works for the frame and for the fabric, contact adhesive.

If problem was in the bellows, Dritz 395 Liquid Stitch Permanent Adhesive would be recommended.

[Jason Greenberg Motamedi]

I have used the Liquid Electrical Tape for a similar project (an ancient and valueless Korona 5x7 camera) and it worked as expected, which is to say it sealed the light leak and remained flexible. I would only recommend as a solution for a cheap camera. It is difficult to remove and pretty much voids resale value.

[AJ Edmondson]

I agree with Jason... I tried it and it sounds like (for your purpose) it would work. I wouldn't use it again to try to repair pinholes!
Joel

[Drew Wiley]

The 3M liquid tape seems better. But the circumstance you're describing needs more of a gasket effect, squeezed together. So a professional black silicone ATV sealant would probably be more appropriate. You need to clean your surfaces first with denatured alcohol.

[rdeloe]

Thanks Drew and others for the advice. My preferred option is to get the seller to send me a replacement with no leaks. However, they probably don't have said replacement around... I could send them the bellows to fix, but that puts my camera out of commission for a good long time, and if they send it to the person who did the job in the first place I'm not optimistic. I've suggested that they let me try to fix it, and take it back if it doesn't work. Depending on what they used to glue the bellows to the frame I may be able to clean it off and re-glue it properly. Or, I might be able to pinpoint the leaks and use a bit of sealant.

Drew: by chance did you mean "RTV" sealant rather than "ATV" sealant? I found something called "Permatex Black RTV Adhesive Sealant" at a local store -- but no "ATV" sealant.

The 3M liquid tape seems better. But the circumstance you're describing needs more of a gasket effect, squeezed together. So a professional black silicone ATV sealant would probably be more appropriate. You need to clean your surfaces first with denatured alcohol.

[Drew Wiley]

RTV is the classification generally used by the several competing manufacturers (esp Dow and 3M) for true industrial applications. ATV is a home center or other retail marketing label, which might carry any number of brand names. The products might or might not be equivalent. But with all silicone caulks, the freshness is always important; and some retailers known for price-cutting tend to take advantage of deals on old, nearly-expired product. Always squeeze the tube to make sure it's easily malleable; and when squeezing out the product, make sure it flows easily. Old product tends to be a bit stiff and stubborn coming out of the tube. The advantage of silicone is that it cures in embedment (doesn't need air evaporation). The disadvantage is that any silicone residue prevents any other kind of product from adhering afterwards. Silicone is a one-way street: once you use it, it's the only kind of product you can use afterwards. But it's available all kinds of places and generally does an excellent job with this kind of thing.

[Greg]

Have had a lot of luck mixing common Elmers white glue 2:1 with lampblack pigment from an artist's supply store. When it dries is still a little bit flexible, and even removeable most of the time. Have used it to fill in small screw holes in a metal lensboard and to repair pinholes in bellows.

[Drew Wiley]

Greg, the problem with that kind of concept is that it does need air to cure. It's just PVA glue. If it traps itself in by surface-drying too fast, then interior drying simply won't happen. There are non-silicone self-curing sealants, but one generally has to deal with specialty suppliers to get straight answers. I am aware of your technique - I've tried it, and many many many more alternatives. We sold over a million dollars of such sealants a year - in a single store! And I tested every one of them first, and a whole lot more that never did make the grade. But I am quite a jerry-rigger myself, and prefer an easier route whenever possible. And yes, it's nice that PVA can be dissolved or pecked out if necessary.

[LabRat]

One head's up is that the dip or liquid tape option can fill tiny holes, but if it is covering a broad section, that area will possibly have some tack in the future, so if is against another folded surface, they can slightly bond, causing damage...

If it is used inside a pinhole, make sure it does not sit too much on the surrounding surface, as that can stick to itself or other surfaces...

If to hold to the lnner frame, a good contact cement should be fine...

Steve K