3D prints: Film Draw Downs

I've been designing and printing my own film applicators, and they've turned into one of my more useful shop-made tools. The problem I was trying to solve: I needed a reliable way to make thin, controlled-thickness films out of adhesives and other materials for conservation treatments, without relying on whatever happens to spread evenly by hand.

The design is simple — a printed bar with a precise gap height, working like a small draw-down applicator. I've printed versions from 0.2mm to 0.6mm. To use one, I lay down a sheet of Mylar as a substrate, put down the adhesive or material, and draw the applicator across it in one pass. That gives me a film of even, repeatable thickness. Once it's cured or dried, it peels off the Mylar cleanly, and I cut it into whatever shapes or sizes the treatment calls for.

I've put these through their paces with a range of adhesives — Lascaux 303 and 498, Plextol B-500, and a few others — making both single- and double-layer films. Depending on the adhesive and how I process it, I've gotten pressure-sensitive films, heat-set films, and plain films with no tack at all.

The application I'm most pleased with so far: archival facsimiles of electrical tape for science and technology collections. I draw a transparent film, tint it with acrylics, and end up with a stand-in for aged electrical tape that doesn't bring degrading rubber adhesive or PVC backing anywhere near the object.

I've got a batch of these applicators listed in my shop now — a few thickness options available, with more sizes coming as I print them.