Sunday, July 20, 2008

Iris Fabrication - Part One

(Originally published July 11, 2008)

I decided to make the iris blades for the viewport out of plastic laminate, the kind that is usually used for countertops. It would be flat, smooth, relatively easy to cut and require not painting as it would be pre-colored. I found a Wilsonart laminate called Alumite that was a sort of mottled aluminum color with a very subtle metallic sparkle. There are some laminates made from real aluminum but they were all too flashy. The laminate was available in two types, a thicker version for countertops and a thinner one for vertical (wall) applications. I chose the thinner one thinking it would close to form a smaller opening in the center. in hindsight, I wished I'd used the thicker one. The thin was just too flimsy and brittle.

First, I printed out a full size paper pattern and spray glued it down to a sheet of 1/2" MDF (medium density fiberboard). This was cut out to the finished shape for use as a routing template. The laminate was rough cut into 8 pieces with a utility knife. I was able to get all 8 blades out of two 4x8 sheets of material.

All 8 sheets were stuck together with double faced paper tape and the template then stuck down to the top of the stack. A flush cutting router bit (also called a laminate trimming bit) was sued in the router table to trim the stack of material to shape. While the blades where still stuck together a row of screw holes was drilled along the outer and overlap edges.

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