I’m making trophies for a Community Group’s Golf outing. I thought the simple design might be of interest to some and wanted to discuss thickness tolerances of Cast Acrylic. First off, here is one of the trophies.
It is made from the first shipment of Proofgrade acrylic and sits in 3 layers of Proofgrade Walnut plywood.
Here are the layers. The bottom is deeply engraved to the thickness of the acrylic. Layer 2 also is set to the thickness at tight tolerances in order to ensure the acrylic is held at exactly a 90 degree angle. The bottom 2 faces are glued together. I put just a small amount of glue in the channel of the bottom piece. It spread upwards slightly and secured the acrylic to the 2nd layer as well as the bottom layer without any oozing above the top.
Here’s what I thought made it just a bit inventive.
The top layer is not glued down and the slot is ever so slightly thicker than the acrylic so it will slide down easily. In order to personalize the trophies quickly, I’ll be waiting for the hosts of the outing to e-mail me the winners. I’ll be able to engrave and cut these pieces while they have the dinner and other banquet festivities. The cuts should take about 40 minutes. They’ll be able to have the blank trophies at the event, then I’ll deliver the personalized top plate before the event is done. If anyone has to leave before I get there, the hosts can easily mail this top plate to them in a standard business envelope.
I even made a carrying tray/display out of some of my nicer scrap cardboard so they can be transported without hassles.
Here’s the problem: I carefully laid out the Walnut bases to fit the first batch of Proofgrade acrylic I got. It was .098" (2.56mm) thick. I cut all of the slotted Walnut to fit that to tight tolerances. I needed to get additional acrylic for the last 12 of the trophies. Proofgrade came in, I cut and engraved them and went to assemble today. This entire batch of Proofgrade was .1195" (2.95mm). Nothing fits and I’m unable to line up the cut walnut in order to widen the slot.
Wasted time in material as well as cutting and design time.
Now - I know that cast acrylic can vary, and I should have thought about it, but is this much of a difference normal? I assume it is, so . . . .
Moral of the story for everyone who hasn’t worked with acrylic before:
Measure before cutting acrylic that requires tight tolerances.
Luckily I ordered extra Maple ply with my acrylic order, or I wouldn’t been able to deliver these for the vent, but I’m out the wasted material and time.