Applying a compliant surface

Got some transparent liquid silicone rubber compound last week and poured it onto the acrylic to act as a compliant surface to help the blobs show up without requiring significant amounts of force. The silicone is supposed to be cured at 23°C for 7 days, so it's been in a box in the spare bedroom since Sunday with the heating jacked up. Had a check tonight and it's looking very promising. The silicone layer is as smooth as silk with no air bubbles or ripples (well, none that I've noticed yet).

Pouring the silicone was pretty nerve wracking. I knew that the compound had to be mixed very precisely (5:1 by weight in my case) and that others had had some issues with air bubbles or their layer remaining tacky after curing. Fortunately it seems to have worked out quite well, although I won't know for sure until I try it out on the table again.

Anywho, on with the pics ...

Silicone compound

The two part compound. The big tub on the right is the silicone rubber itself, while the small bottle on the left is the catalyst.

Measuring the compound

Weighing out the components with the only scales I could lay my hands on.

Mixing the compound

20 minutes of stirring later. Getting slightly worried about the number of air bubbles.

Spreader

The spreader. Made using some of the MDF off-cuts and a piece of pine dowel. The MDF is 9mm thick compared to the acrylic's 8mm. So, I should end up with a nice 1mm silicone layer. Underneath the spreader is a big ass sheet of cellophane to protect the dining table.

Compliant layer applied

Silicone applied and ready to stashed for curing. At this point I was already chuffed with how smooth it was looking. As you can tell from the large puddle of silicone, it was pretty difficult to judge how much to apply.

Should be testing the compliant layer early next week and I'll post an update here shortly afterwards.

Published

01.02.2008

Category

Multitouch

Tags

  • Multitouch