Tuesday, November 3, 2020

Making a camera with double faced tape instead of glue

Occasionally on the Lensless Podcast, when homemade cameras come up, I hear guests question the durability of cardboard and I think I can hear them wrinkle their noses when mentioning they have to use glue. Some kits I see that use cardboard to make a camera often prominently state “no gluing necessary.”

I don’t have any such prejudice against glue or cardboard. I’ve been happily making and using cameras made with them for years.

However, sometimes when I’m thinking about conducting a pinhole photography workshop which includes making a camera, the time it takes for glue to dry and the necessity for everyone to have enough clamps, seems like a limiting factor. I wondered if permanent double stick adhesives would work as a replacement for the glue.   

There are a variety of products available in sheets and in rolls of tape. Most have a release layer on one or both sides which you peel off to reveal the adhesive. There are also a variety of thicknesses from mounting foam to paper-thin. I would need something pretty flat to take the place of a layer of glue. I went down to my local hardware store. They only had two possibilities. One was dispensers of half-inch (12mm) Scotch Double Sided Tape (“No glue mess”), which doesn’t include a release layer. I thought it would be impossible to apply and handle without sticking to everything. The other was this Duck Carpet Tape. It’s described as “Tear resistant cloth” so I was concerned it would be a little thick, but I decided to give it a try. It’s also an inch and a half (36mm) wide so I wouldn’t have to apply so many strips to make a continuous layer.

I decided to use the Evil Cube Template for my experiment. It’s more complicated than a Populist so I thought that would make for a good test. To make things slightly more tricky, I also decided to make something from a package where an image could be aligned on the shutter and the camera body. I had this carton from a 12 pack of Fantasy Factory beer from Karben4 Brewing in Madison I’d been saving for a while that seemed appropriate to the season. The cardstock is a little heavier than usual and combined with the thickness of the tape it was a little concerning, but this is a test so I went with it.

I laid down strips of the tape on the template. I quickly discovered that I couldn’t cut it with my regular scissors because it stuck to the cutting edge and also left a sticky residue on the blade. I eventually found that I could lightly place it on my cutting mat, cut it with an Xacto knife and carefully peel it off without the adhesive detaching from the release layer.

One nice thing about having the separate strips is that you could peel the release layer off one strip, attach that and then continue peeling and attaching. That was much easier than trying to manipulate a large area with the exposed adhesive.

It did work, but I think a simpler non-glue solution would be to print the template on adhesive labels for laser and inkjet printers. They are available in full size sheets that come with multiple slits on the release layer so you could use the same method to stick and peel a step and a time. During the pandemic, I’ve been printing templates using the Public Library’s very excellent curbside printing service, so I couldn’t try that.

When it came to assembling the camera, it was easy to place the tape where I needed, turn it over and cut it to the edge with my craft knife.

It initially seemed difficult to work with but once I got used to it, it worked pretty well. The adhesive bonds instantly and is very strong. There’s something very gratifying about that instant bond and being able to go on working right away.

There were two worrying issues. 

It does add some thickness to things. That wasn’t really a problem with the 60mm distance to the pinhole in this camera, but with a very wide angle camera, it might not be able to make the shutter thin enough that it didn’t block the edges of the image.

The other issue with this particular carpet tape is that the adhesive layer includes a cloth mesh.

In cases where you needed a double layer of cardstock, that would also have two layers of this stuff attaching the template, a cut edge turned out to be sticky. It left little beads of adhesive at the ends of those threads. That could be a problem where you had moving parts. I discovered this fairly soon with the little stop which keeps the film reel parallel. Initially I had trouble rotating an empty film reel. I eventually covered the edge with a thin strip of tape. 

The other place where it would really be a problem was with the sliding shutter. I eventually discovered that repeated scraping with the edge of my Xacto blade could get rid of most of it and a little work with sandpaper could remove the adhesive enough that the parts would slide without sticking.

I couldn’t quite figure out how to attach a knob to the winders with the carpet tape so I just reused some from another camera.

In order to determine how well this all worked, one has to expose some film. The first nine frames I did around the house with the axial pinhole. In order to give it a proper test I had to get out in the sunshine and try out the rising pinhole.

I encountered an interesting problem that had nothing to do with the adhesive.

When I first pulled the negatives out of the wash, those last three frames looked a little dense which made me wonder if the camera wasn’t really light proof. I’ve never had a problem with leaks with an Evil Cube and with that extra heavy cardstock that consists of a double layer everywhere but the back of the camera, it didn’t seem likely that it wasn’t completely opaque. On closer inspection, the darker parts of the image looked completely clear, so that wasn’t it.

When I scanned the negative I discovered that there was a double image on the top half of each one of these negatives. I was pretty sure I hadn’t opened the lower shutter accidentally on all three pictures.

With the 60mm pinhole distance and a separate opening for each pinhole with a divider between them, it also didn’t seem likely that the lower pinhole was seeing through a gap at the top like I experienced with the ultra wide setting on the Pinhole Lab Camera.

When I mounted the pinholes, I looked from the inside and tried to get the pinhole as centered as I could in the openings. I just taped them down enough to hold them in place.

What this cursory inspection didn’t show was that the brass didn’t completely cover the opening and there was a very narrow gap at the bottom. That small slit created a second, not quite as sharp image. Enough of it was blocked by that extra thick shutter that it only exposed the top of picture.

The first nine pictures with the axial pinhole turned out just fine.

These decorative brassicas are very popular with the flower vendors this late in the season.

A candy jar full of M&M’s by the living room window.

The stage of the microscope.

Who knew that spider plants produced flowers at the end of those runners?

A little sunlit succulent in the south kitchen window.

A collection of Sarah’s makeup brushes.

The key rack by the door has an extra function this year.

The haul from the last outdoor Farmers’ Market of the season.

This was all happening on the day before Halloween. I took advantage of this pumpkin stem before cutting the hole to clean the insides.

The carpet tape seems to be a workable solution. It held up well shooting the roll of film and numerous openings of the camera investigating that double image problem.

The Fantasy Factory Cube has two hand-drilled .30mm pinholes, on the film axis and 13mm above the axis, 60mm from the film plane.  The film is T-Max 100 semi-stand developed in Rodinal 1:100.

Later edit: One problem with the double face adhesive is that you have one chance to get it adhered. If you get it slightly out of alignment, you don’t get a chance to reposition. With the small parts involved in the Evil Cube, I didn’t have much trouble, but with larger pieces it’s difficult to keep things straight.

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