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

[rdeloe]

Things are getting more complicated. There appear to be two sources of light leaks where the bellows mounts to the back end of the camera (a Wista 45VX). The

1. It looks like the person who made the bellows used a clear glue to attach the bellows to the frame. It smells like Gorilla Glue. Where it's a thicker layer of glue, a bit of light can shine through.
2. The foam seals don't seam to be making good contact with the bellows frame. The seals aren't rotted out so they're either compressed, or someone replaced them with too thin foam.

For problem #1 a bit of silicone caulk should help by covering over the clear glue and filling in any spaces that weren't glued down properly. For problem #2, I could make thicker seals -- but that creates a whole new problem. The bellows already don't compress enough to easily fit into the body and allow the camera to fold shut. Making those seals thicker makes it impossible to close.

So now a new question... am I making a mountain out of a molehill? My test setup is a lightbulb equivalent to a 60W incandescent mounted to a lensboard and shining inside the camera. The light leakage is at the rear (sadly right next to the film) but it's within the cavity of the Wista 45VX body. It's only visible close in to the camera, looking straight into the body cavity from the lens side. I've been presuming that if I can see any light coming out -- anywhere -- then I can expect ruined shots due to light coming in, especially during longer exposures. What do we think? Are your cameras 100% light proof? Do you check?

[LabRat]

Problem 1 can be solved with painting the clear glue with black acrylic paint from the art store...

For #2, where exactly is the foam??? Is it on the inside or outside back??? Are you seeing light through them when the foam is compressed, or uncompressed??? Foam might have some light coming through the pores uncompressed, but will close when pressure is applied... Or is it just not making contact??? Depends, but there are options...

Steve K

[rdeloe]

Foam seals are shown in the picture, below. The bellows simply press against that foam square. They clip in at the bottom and at the top; you can see the bottom clip but the top clip is out of view. By the way, this is the "body cavity" I mentioned earlier. The entire front standard and the bellows are stored in this space when the camera is closed. It's clever and well designed.

I've seen lots of rotten foam seals. These don't look rotten. They also don't look like replacements unless the person doing the work was extremely neat and careful. The bellows frame is nice and straight so that's not the issue. I'm starting to think this isn't so much a "bug" as a "feature". ;) That's why I asked about "zero tolerance". Is it even possible to eliminate 100% of possible light leaks from all sources (screws, film holders, bellows, etc.)?

And as a fun aside, I've also been searching the forum for advice on light leaks. It seems I'm not the first person to ask... Here's a great post from a couple years ago. The gist of it is "light leaks are a thing -- get over it and drape your dark cloth over your camera. Harumph." As usual we seem to divide nicely into two groups of people: those who have zero tolerance for imperfections (and light leaks), and those who throw their dark cloth over the camera.
https://www.largeformatphotography.info/forum/showthread.php?138269-Stop-Light-Leaks-Use-your-dark-cloth

186311


Problem 1 can be solved with painting the clear glue with black acrylic paint from the art store...

For #2, where exactly is the foam??? Is it on the inside or outside back??? Are you seeing light through them when the foam is compressed, or uncompressed??? Foam might have some light coming through the pores uncompressed, but will close when pressure is applied... Or is it just not making contact??? Depends, but there are options...

Steve K

[LabRat]

So that just seals the bellows to the frame???

It probably never much has been removed, so it probably compressed, even if still not melted, so I'd vote for replacement while parts are availible... It shouldn't cost too much for the foam kit...

I'm of the school of what can go wrong, will, so given the choice...

There are strip foams on a roll that might work at your home store if you can't get a kit... Even the grey light foam will seal off light once compressed enough...

Good luck!!!

Steve K

[rdeloe]

On really close inspection, the foam looks to be in good condition, but it's definitely compressed in places. It's an easy repair if I can find the right material. I had some weather sealing foam strips handy for comparison. The concept will work -- I just need to find a slightly thinner one.

Thanks for all the advice folks. I think this is entirely and fairly easily fixable.

Rob


So that just seals the bellows to the frame???

It probably never much has been removed, so it probably compressed, even if still not melted, so I'd vote for replacement while parts are availible... It shouldn't cost too much for the foam kit...

I'm of the school of what can go wrong, will, so given the choice...

There are strip foams on a roll that might work at your home store if you can't get a kit... Even the grey light foam will seal off light once compressed enough...

Good luck!!!

Steve K

[Sfroza]

I have had good results with urethane poron foam. It remains flexible through the range of temperatures that we work with. It can be found with pressure sensitive adhesive and in a multitude of thicknesses, lengths, and widths.

Michael

[Pieter]

I have used wetsuit repair glue.

[rdeloe]

To close the circle on this thread, I fixed the light leak in the bellows. Following advice received in this thread, the product I used is called "Permatex Adhesive Sealant -- Black Silicone". It's an "Automotive grade RTV sealant".

The person who put the bellows together glued the bellows to the frame with a translucent glue, and may have also left some tiny gaps. That's obviously not good in terms of light leaks. A very thin layer of this black silicone product around the join filled the gaps and covered the glue. Not only does it look better, but also there are no light leaks. You and 30 of your friends can all fix your bellows from one 80ml tube of this stuff. ;)

I mentioned this in another thread, but part of the light leak in my bellows was due to a worn out light seal where the bellows met the camera body. If you happen to be using a Wista 45 series metal camera, the foam you want is 2mm thick. The one I used is either an open cell or semi-open cell; it's compressible, but it doesn't feel as thick and dense as closed cell foam that you'll find in the insulation aisle of your local hardware store; that stuff is too thick and too dense for this purpose.

[alexvaras]

For micro holes I use Liquid Electrical Tape from the inside, very small portions, let dry 24hours and check, if still there (unlikely) do again. The bellows I face normally are from german folding cameras. I will try this other mentioned since I read it could have less odor.

[archphotofisher]

I use this product from Bostick-sullivan, it works!


https://www.bostick-sullivan.com/cart/6.html#product-details-tab-description

Zoom image
Bellows Patch Kit
$15.00
225ml black flexible bellows patch and 18 inches of Dacron white reinforcing fabric

[Greg]

So based on this thread, I dug out an old Sinar 8x10 Norma bellows that had more than a few pinholes in the corners of the back third of the bellows. Used Gardner Bender Liquid Electrical tape that I got from the local ACE Hardware store.

My experiences:
1. It is not 100% opaque if applied as a thin "painted" layer.
2. Is very volatile (easily evaporated at normal temperatures) when applied with a thin brush. After dipping a small thin brush into the container, one has less than 10 seconds to apply it. Secret was to get a drop of it at the end of the brush and apply the drop to the pinhole. One pinhole at a time.
3. Frosted "Standard" shaped LED light bulbs are a God sent. The one I used was a 13 watt LED bulb. Nice thing was that because it doesn't heat up, I was able to run the bright bulb up and down inside the bellows touching the bellows but not worrying that it would damage the bellows.
4. Did my repairs in the darkroom with the safe light on and the exhaust fan on. Pinholes were darn easy to see and the light from the safelight was just bright enough to make out the outer surface of the bellows. Exhaust fan took care of removing the smell of the liquid tape.
5. The bellows was ready to use pretty much right after applying the last drop of liquid electrical tape. The stuff really dries fast. My previous pinhole fix of Elmers glue and lamp black gouache took easily overnight to cure/dry.

[Drew Wiley]

This is vinyl-based, so itself will slowly degrade or lose its flexibility with UV exposure and weather. I prefer the longevity of black silicones; but they have their own downside in being incompatible with anything else atop them later, and not always fresh or of the highest quality when bought from ordinary outlets like hardware stores. I'd prefer to clean the bellow well first, apply something like thin black nylon tent repair tape to the failed area first, and then the black liquid patch atop that if possible. But having an unopened little can of the liquid electrical tape along in an emergency camera repair kit is a good idea if your bellow are already beginning to look a little suspect. I alway have a small amount of nylon tent repair tape in my pack anyway, for sake of actual tent leaks, but hypothetically usable on a parka, sleeping bag, or bellows too.

I haven't actually been in that predicament for a long time, and all my current bellows are in superb condition. Anything over-used with pleat pinholes got converted into a compendium shade instead. That's especially easy to do with the Sinar accessories system.