Introduction: Segmented Corian Pen
Runner Up in the
GIFs Challenge 2017
On previous pens, I've either had enough material to cut the full sized blank in a single piece, or with the Corian, I was gluing up thickness with two pieces that already had enough length and width. That's great if you have chunks of reclaimed countertop, but what about the tiny sample squares?
After picking out colors from a sample set, you're left with a few dozen 2x2" squares of 1/2" Corian. In taking stock of what I had left to play with, I thought a handful looked almost like a paint swatch and had a sort of ombre vibe. Lightbulb!
Step 1: Scuff, Glue, and Clamp
Through trial and error, I determined that it is best to rough up the sides of the material before gluing. They're already flat, but we need a little roughness or tooth for the adhesive to grab. I use some 80 grit sandpaper on the top of my table saw and wipe away the excess dust. I've previously used Medium CA glue, but find that in this material, the expanding properties of the Gorilla Glue make it a better choice, especially when gluing in the brass tubes, but we'll get to that later.
Make sure to smear it all over the surfaces. Clamp tight and wait. There's lots of squeeze out. Gloves are a good idea.
Step 2: Dividing the Blank
Average pen blanks are about 3/4x3/4" - since our squares are 2" we should be able to get 4 half-blanks out of each. Depending on the amount of glue squeeze out and how straight you were able to keep the edges during gluing, you might be able to cut it in half on the table saw without any kind of jointing. Since we have about half an inch of extra material in each direction, it isn't a big deal if we're a little off.
I set my table saw fence an inch from the blade and cut just slightly more than half the height of the block. I then flip the block end over end so that the same face is against the fence but we're cutting through the facet that was pointed skyward in the previous cut. We can then cut the two resultant pieces in half as well. If you want, you can reset the fence to 3/4" or so and trim the blanks square, but it's really a matter of personal preference.
Step 3: Drilling and Tubing
Mark a line from corner to corner, forming an X on one end of each blank. This will give us center. I've done these with a handheld drill, but have had MUCH better results with a drill press. Mine doesn't have the travel to do the full blank in one pass, so I drill to it's range, turn off the tool, slide the blank up the bit, and place a sacrificial 2x4 under the blank. This not only raises the blank so that the bit can reach the bottom, but gives it backing to protect against a blow-out when the bit exits the blank.
Now that the blanks are drilled, we can scuff up the brass tubes and glue them into the blanks. Scuffing them will give the adhesive something to grasp. Without this step, the tube my spin in the body of the pen. Pour adhesion can often be heard while turning due to excess vibration in the blank. I used to use Medium viscosity CA Glue, but I've had much better luck using the expanding Gorilla Glue. There is a downside in the cure time and ooze-out, but I have much less blow-out on the lathe and less problem with glue adhesion. Corian is also susceptible to having the hole come out more ovular when drilling, so the expansion of the glue cuts down that as well. Using a drill press, clearing the waste often, and taking small bites out of the material will help keep the hole from being distorted.
Step 4: Rough Turning
If you didn't do so already, I highly recommend scraping off the excess gorilla glue before placing your blanks on the mandrel. I like to use two bushings on the headstock side to give me more working room, then one each between the blanks and before the knurled nut. Following general lathe safety, we do all of this work with the tool powered off. Bring the tailstock up to support the mandrel, locking the base in place, snugging the tail with the adjustment wheel, and locking the fine adjustment lever in place. Spin the headstock wheel to ensure that the mandrel is turning the live center in the tailstock.
Move the tool rest up near the blank so that nothing will come into contact with the tool rest. Ensure that the distance and height allow the tool to make contact where desired around the center of the work piece.
We'll start by getting the pieces round. I use a roughing gouge. Because it's still very square, the lathe is on it's slowest setting and I'm taking light passes. You can stop the lathe periodically to check progress. Likewise, you can rest the smooth round of your gouge against the work piece while it spins. If there's chatter, you know there are still flat spots, but if it's smooth, you've gotten it round!
Step 5: Final Shaping
Shape is certainly a personal preference. The key with pen kits is to get the material thickness to meet the bushings at each end, regardless of kit style or bushing size. Each bushing is matched to the part of the pen kit that makes contact with the pen. You either want to blend the body of the material to the hardware, or accentuate the difference and make it look as if the hardware is restraining the material, though this is often more difficult to pull-off.
I've tried lots of different techniques for shaping, but once round, my favorite tool is the skew chisel. Get it sharp, turn up the speed, and the Corian peels off in long ribbons!
Step 6: Finishing
Once I've got the shape to where I'm pleased, it's time to sand. With sharp tools and clean tool lines, the acrylic can easily start sanding at 220 grit. It's at this point that we can fine tune any difference between the blank and the bushings if we didn't quite meet up with the chisels, though it's best to get as close as possible with the tools.
I go from 220 to 320, then wet sand 320 and move to micromesh pads. They have their own rating system, but I go through all the pads up to 12000, checking for scratches as I go. I sand while under power at a slightly slower speed than when using the skew, then turn the lathe off and sand end-to-end where needed if there are any scratches. You want to see a slurry develop on the pad while wet sanding to know you're removing the previous grit's scratches. At a certain point, this may disappear and we're merely polishing the blank.
After 12000, I check everything once more and apply car polish/rubbing compound with a napkin. Do this with the lathe turned off until fully-applied, then turn it on and buff using light pressure. The pressure will cause the compound to heat up and polish out to a gleaming shine. There's really nothing like well-polished plastic.
Step 7: Glamor Shots
I'm obsessed with turning solid surface plastics. The color and pattern palette is practically endless! I hope this inspires some of you to take a look at different materials (scraps and trash, even!) around you and make something!
I'd love to hear from you in the comments and see what you're turning! If you liked this project, please be sure to vote/favorite/follow and check out the full video. I have lots of other articles on everything from sock puppets to crazy-cheap laundry detergent.
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