I printed out the WizardofFlight Knee armor templates as a basis for my knee armor. As with the helmet template, I transferred and cut these pieces out of poster paper. After a few minutes of head scratching, I finally got these pieces arranged in the correct format.
I went ahead and attached the pieces together. I used hot glue to attach most of the pieces, but I found that I could use tape to attach the non-structural parts. As this was just a rough mockup, I wasn't especially concerned with building the model with perfect accuracy.
To make sure the knees would keep the right shape, I cut off two strips of my aluminum sheeting and used them as supports. I clamped it up with a pair of binder clips and then superglued them together. After the superglue dried, the knees held their shape really well. The only issue I had was that the superglue is very brittle. If they bent or moved, the superglued pieces snapped right off.
These pieces were great proofs-of-concept, but they weren't very practical. I wouldn't be able to wear these without them breaking, and I didn't particularly want to fiberglass these too.
I reprinted these pieces and took them back down to my lab. I ran to Home Depot to pick up a pipe saw and some PVC piping. Unfortunately, they only had 10 foot lengths of the 3 inch PVC piping. Talk about overkill, right?
I taped my template to the pipe with some of my packing tape and traced a rough outline of the paper with sharpie. This is one piece where it's important to be true to the template, otherwise the knee pieces could end up shaped differently.
I used my pipe saw to cut out the pieces for the knee pads. Normally, these pieces would be very difficult to cut without some type of tabletop vice. Luckily I had access to several of these at TCNJ.
I clamped these pieces lengthwise in the tabletop vice. Otherwise, they'd be bouncing around as I tried to make each cut. The next two cuts I made went down the back of the pipe. These cuts would eventually form the back of the knee pad, and let me pry these apart.
The pipe saw I originally used was great for making big, straight cuts. Because it has a really wide blade, it doesn't do curves particularly well. To cut those tight curves, I ended up using a 6" coping saw.
These cuts were pretty rough and needed some serious cleanup work afterwards. I used my dremel's sanding drum to round off the sharp edges and clean off any burrs from the saw.
I might have been overenthusiastic with the sanding drum and accidentally created a few divots in the along the edges. This isn't a huge problem, but in hindsight, I probably could have used a bit of MDF and sandpaper.
Sanding these pieces created an amazing amount of PVC dust. Even though I had a respirator on, the dust from the dremel turned my face completely white. The next time I do this, I'll pick up a set of sealed googles.
Once I finished sanding my pieces, it was time to start shaping them. To bend the PVC, I had to significantly heat them up. Some people choose to heat their pieces in an oven, but I chose to use my heat gun. The PVC gets gets really, really hot before it becomes malleable enough to bend, so these leather gloves were an absolute necessity.
I started by heating up a side tab and then flattening it with a thick block of plywood. PVC takes a long time to heat up before becoming malleable, but if you take your time with it, you can avoid burning the plastic or bubbling the material. The key to evenly heating the PVC is using the heat gun at a high setting and evenly heat the entire area.
The next step would be flattening the sides of each knee pad. Once I had sufficiently heated each side, I took a scrap piece of plywood and applied pressure. Using plywood had two benefits; it kept my hands from making contact with the hot PVC, and it ensured that I had completely flattened each tab.
I found out that PVC holds its heat really well. The first piece took almost 30 minutes to cool down enough to touch without gloves. Afterwards, I decided it would be quicker to dunk it in a bucket of water. Once I had pulled both pieces it out of the water, I had a nice pair of knee pads.
My next step will be to drill holes in these pieces. I'll start mounting straps to these pieces.
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