We are planning to use polycarbonate for our intake but had a few questions.
Our polycarbonate is .107 (I think). We feel this would be too thin alone so we plan to double it and use hardware to secure the pieces together. Are there any problems with doubling the layers? (We will have the pieces cut on a CNC router so alignment shouldn’t be a problem)
We can cut thin plywood (3mm) on a laser, would sandwiching a piece of that in between 2 layers of poly be beneficial at all?
We also noticed multiwall poly available at Lowe’s. It is thicker and feels more rigid than the poly we have. Would this make a better intake? We feel it wouldn’t hold bearings well, but we have never used poly in any form before so we don’t know if it would work or not.
Using multiple layers of thin polycarbonate is actually a very good way to get strength with flexibility, and is often used for intakes. We considered doing just that for this year. You do not need to reinforce it with plywood or anything else
0.107 polycarb is likely strong enough for your needs. If you feel the bearings are not held tightly enough you can selectively strengthen the area immediately surrounding the bearing holes. The multiwall polycarb is definitely more rigid, but each wall is quite thin and may not be strong enough to support a bearing well. Again, a little reinforcement can solve that. My personal opinion is that there is no need to completely double up the entire thing, nor to reinforce it with plywood.
But you asked specific questions:
It seems thick enough. No, you can double it without problems.
Not needed, but you can do this as long as you are OK with not being able to see into the intake.
Thicker but not as strong, as the individual walls (faces, internal ribs) are thinner.
In general, polycarbonate can be thought of as clear aluminum. It can be bent cold, doesn’t shatter easily, and is stronger than it seems.
We used an intake 2 years ago with 1/8" polycarbonate. 2 layers with the belts between and spacers. Worked great.
I wouldn’t use the polycarbonate cardboard stuff for small parts. Big panels, sure!!! When the rib spacing is a significant fraction of a part’s dimensions you will get in trouble. Ie, 5 ribs across your part = bad. Also easy to crush with bolts…
1/8 is a little thin but the game pieces are so light that I can’t really see how it would be a Problem.
Other posters have pointed out the bearings issue, doubling up just around those might be a good idea.
You could also add a bend to get stiffness without laminating
If you decide to laminate the whole thing anyway, putting strips of VHB in the middle will be much stiffer/stronger than standard fasteners alone.
Bolts or rivets will let the panels slide at microscale relative each other, eliminating that with VHB tape will significantly stiffen.