Introduction: Rocket Pen
And I think it's gonna be a long, long time
Till touch down brings me 'round again to find
I'm not the pen they think I am at home
Oh, no, no, no, I'm a rocket pen
Rocket pen using up its ink up here alone
The rocket pen is a fun project requiring a variety of techniques to make. Don't let that intimidate you. We made this for our Halifax Makerspace YouTube channel (please like and subscribe!) for a No Lathe Pen Challenge. If you need help finding parts or tools (especially a laser cutter), reach out to your nearest makerspace.
We're entering this in the Trash to Treasure contest. Please vote for us! The acrylic is scrap from our local science center, the button is made from a chopstick I made that had some tearout, and the walnut came from an old bedframe.
Step 1: Electronics
The electronics can be done in several ways. You can easily forego etching the circuit board, and make either a "dead bug" circuit (directly wiring things together with no substrate) or perf board circuit.
I made the electronic module first, because I based the size of the pen around it. You'll need:
- 1220 battery cell (3V) and SMD holder
- white through-hole LED
- latching push button miniature switch
- printed circuit board
- 150 ohm surface mount resistor
Lay the parts out on the circuit board as shown in the picture. Score it with a utility knife and snap it to fit the parts. Use a Sharpie to draw a circuit on the PCB that will connect all the components. It doesn't matter what order it's all in.
Once your circuit is drawn, pop it into ferric chloride for 10 minutes or however long it takes to etch away all the exposed copper. Take it out (with gloves if you're sensitive to it or don't want to stain your fingers) and wipe the Sharpie off with acetone.
Solder the parts in place. The only thing that matters is that the LED be oriented the right way. The longer lead is positive, the shorter negative. If you test it backwards, there will be no permanent ill effects, it simply won't light, so just turn it around.
Step 2: Wood Top
The wood top would best be made with a lathe. Since we made this pen for a No Lathe Pen Challenge, we'll present how to do it without one. Cut a piece of 1"x1" hardwood so it is the length of the circuit board and switch, plus 1/4 inch. Drill it with a 3/4" forstener bit, stopping 1/8" shy of drilling all the way through. Drill the rest of the way with a 1/4" bit, with a backer board to prevent tearout.
Use a quarter or compass to mark the top of the block. Round it carefully to the line on a belt sander. This should leave 1/8" walls all around, with a 1/4 button hole on top. Sand and finish. I used beeswax and mineral oil because there's no drying time needed, but polyurethane might be a better long-term finish.
For the button, make a dowel just shy of 1/4". You can do this by chucking a 1/4 x 1/4" piece of hardwood in a drill and apply sandpaper as it turns. I had a chopstick that I'd made very poorly, so i reused that. Cut it 3/8" long or so and round one end. Cut a circle of any type of wood, 5/8" in diameter and 1/8" thick. Glue the button, centered, to the circle. The circle stops the button from falling out of the pen. Apply finish to the button.
Step 3: Laser Cutting
Laser cut 5 rocket ribs from .06" acrylic, and the three support rings. Sketchup file is included. Your local makerspace is an excellent place to learn more about laser cutters.
Step 4: Assembly
Do a test fit of the acrylic pieces, and adjust as necessary. Everything should be loose until you insert a pen cartridge from a standard Bic pen. I'm not sure of the style of pen, but they are ubiquitous, clear and about $2 for ten.
This next part is a bit tricky. Carve channels in the inside of the wood top to receive the acrylic tabs. I had to file the tabs quite a bit (they are bigger than needed). Be careful, as you only have 1/8 or so of wood to work with. The idea is, you will be able to snugly get the wood top on without the pen cartridge inserted. Then inserting the cartridge will tighten it up. It's a bit tricky because the LED protrudes into the arcylic, but it can be done! I initially carved out too much, leaving a loose top. I was able to tighten it by adding a drop of Bondic, a wonderful UV-curing polymer with a precision applicator, to the channels (available at most hardware stores near the glues).
Assemble the pen by inserting the button in the wood top, then the electronics. Assemble the acrylic pieces. Add the wood top assembly to the acrylic assembly. Insert the pen cartridge to finish. Congratulations, you have a rocket pen! Test the button. If it sticks at all, apply some beeswax or paste wax to the button and button hole.
Step 5: All About That Base
Now you need some kind of cap. I chose to make a base, inspired by the 1902 silent film, A Trip to the Moon. Cut a styrofoam ball in half and trace it onto a 1/4" board. Cut the board and hot glue the two pieces. Drill a hole in the styrofoam. Cover with air-dry clay and form craters. Use a pencil to add textures and surface features. Use a stiff wire brush to make a dusty-looking surface with a poking motion, not a brushing motion. Allow to dry. Fill any cracks with more clay or epoxy.
Paint. I used spray paint: black, gray and a smattering of white and red. Finish with clear coat.
Add some stick-on rubber feet and call it done!
Also shown is twitter user @Pretti_Ugli's version of a base (photo used with permission), with an actual face. If your sculpting ability is up to it, try this instead!