Adding Polycarbonate Viewing Panes to Kid's Room
The Kids Room will be a great place for the "littles" to start their making journey. But, to be a good learning environment, it needs to be a safe one. Those viewing portals into MetalWorx, CNC plasma room, and the Woodshop need panes installed. The panes need to be tough and they need to be clear. Over the next few days, we'll be cutting, edging, polishing, and installing the panes.
We'll be using 1/2" thick polycarbonate. You may have seen the large sheets of this stuff laying around the shop. It is amazingly tough stuff. This thickness is just shy of the thickness required for bullet proofing! Though super tough, it is easy to tool...assuming you can manage the very heavy sheets (100 lbs/sheet). Unfortunately, it is also very easy to scratch. These sheets have a long history of abuse. Not to worry though, when we're done with them, every scratch and dent will be erased. You might be asking, "Why use such expensive stuff?" Well, we have the right amount hanging around here and it was originally reclaimed from another organization's "throw out" pile (crazy!)
The viewing portals from the Kids' room into each shop are framed in galvanized steel. At this point the openings in Kids' room have been trimmed in aluminum angle (Figure 1) and each needs a polycarbonate pane installed.
Figure 1: Open View Into Woodshop
Preparing the Openings
One of the primary goals of the panes is to seal the Kids' Room from shop fumes and dust...especially from the Plasma Room and MetalWorx. We also want the opening sill to be deep enough to rest little elbows. So, the design is to have the panes overlap the window on the shop side. Making the pane flush with the shop wall will also eliminate ledges that gather dust.
Figure 2 shows how we cut back the wall board on the shop side of the openings. This particular opening is in MetalWorx. So, you can see the concrete board addition to the standard 1/2" drywall. The process went something like this:
- Frame and drywall the opening
- Cut the polycarbonate to overlap 1/2" all around the opening.
- Use the actual pane to transfer the actual shape onto the wall.
- Cut using knife...or an angle grinder with masonry disk for the MetalWorx opening (easiest way to manage the concrete board)
Figure 2: Shopside of viewing portal in MetalWorx
BTW Using an angle grinder (or any powered cutter) on drywall is a serious dust-cloud generator! Having an active shop vac helped a lot...but the fine-particulate respirator was the real life saver.
Figure 3: Ripping and squaring sections on the Sawstop table saw.
Figure 4: Crosscuts with the Makita track saw.
Roughing the Pane
Okay, that's the background stuff. Now, to business. The largest opening measures about 36" x 62." Cutting this from a 4'x8' sheet of poly isn't something you want to mess up on (this stuff costs hundreds of dollars for a sheet). With a pro-grade Sawstop and generous outfeed table ripping the sheet down was uneventful. Even at 100 lbs, ripping the sheet was easy for a single person.
However, cross cutting something this long (and very bendy) on a table saw would be foolish. There are several problems that arise. First, the potential for kickback goes up sharply in cross cut scenario. Second, these poly sheets are not only heavy, they are very flexible. That's an ugly combination when handling the pieces with a single person. The Makita track saw is perfect for the challenge. Unlike most circular saws, this setup is able to make extremely precise cuts without chip-out. The custom track aligns with your marks perfecting and the saw moves along the track effortlessly. Just plop the piece on a workbench, lay the track on the marks, and cut. Easy Peasy.
We could call it quits and move on to polishing the pane. However, past experience has taught me that the cut edges of polycarbonate can be dangerously sharp! Rather than sanding irregularly, I loaded up a chamfer bit in the router and put a tiny bevel all around. Now, it is safe to handle...and has a nice refined look.
Figure 5: Adding chamfer with router.
Edge guided router bits are a great resource. They come in all shapes and sizes for contouring edges. The bearing on this one adds to the precision and life of the bit. You have to look pretty closely to see the tiny bevel that is being added to the poly-sheet. But it is there. And my un-cut hands really appreciate it.
Polishing the Polycarbonate
You might not be able to tell from the picture, but this plastic sheeting has been really abused during its life. It is scuffed and scraped and has various crud across much of the surface. This is part of why it was thrown out. But, it remains very redeemable. You'll be amazed what a random orbital sander, broad range of grits, and a little patience will accomplish. Here's what we'll be doing over the next few days:
- targeted wet-sanding with the orbital sander and increasingly fine grit (starting with 120 and moving up to 800 grit paper)
- wet-sand entire surface with 1000-3000 grit paper
- use palm polisher to treat with Novus 3-2-1 plastic polish system
- Turn attention to each of the other openings and do the whole process again.
Want to try your hand at it?
If you want to learn to use the angle grinder, table saw, cross-cut saw, fixed base router, orbital sander, or palm polisher, now is a good time to give it a whirl. If you have never worked with plastics, this is a great opportunity for you to pick up new skills. Just let us know you're interested and we'll work the project around your schedule.
Let's build something...together.