Introduction: FOAM DOWN
Hello! My name is Mason Choi, and I present to you my thesis project at Emily Carr University of Art and Design:
The reactive target system for Nerf guns or other indoor-rated projectiles. With this system, simple shooting competitions can be organized in the comfort of your own home.
Instead of shooting at friends and family, point your blasters at these targets! Made from laser cut acrylic sheets and carefully milled hardwood, these attractive targets can provide opportunity to compete with your colleagues in a engaging and safe manner.
Recognizing that foam dart guns are safe for children to shoot at each other, does not mean that children should be taught to shoot guns at each other. I propose that proper firearm safety practices should be taught at an early age.
Inspired by the excitement of shooting sports played around the world, I designed these targets with such games in mind. The incorporation of a shot timer is also possible, with a smartphone set behind the target. Also, the target can be configured to "rebound" or self reset with the use of magnets. Slight modification to this design would be needed, I will go over where in this instructable!
In this tutorial I will show you how to make the targets as I did.
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Step 1: Things You Will Need:
[All quantities will be for two targets, multiplication is required to make more]
Alder or maple: at least 1' x 1.5" to fit through machinery
2 x 4" of 1/4" rod -- available at most hardware stores
1/8" acrylic sheet: approx 1 square foot -- a quick online search in my area led me to purchase my acrylic from Associated Plastics.
Machines you will need:
Disc or belt sander
Pneumatic palm sander
Step 2: Other Things You Need:
Hand tools you will need:
Hacksaw 18t blade
Lots of clamps
Double sided tape
Sandpaper 120 to 600 grit
If you choose to make the target self reset, you will need to get some rare earth magnets. Mine are 3/16" thick and about 3/4" in diameter. I found mine at Lee's Electronics.
You can also choose to attach suction cups to the targets, the ones that I purchased attach by use of a dovetail cut into the back of the target. The suction cups can be found at dollar stores.
Step 3: The Plan
The dimensions of the target is attached to this step, a PDF technical drawing.
Also attached is an Adobe Illustrator file for the laser cut acrylic. Changes can be made to create other shapes of targets. The possibilities are virtually endless!
An important note: The file is currently set up to cut with the laser cutters at Emily Carr University, you should check with your local laser cutting facility how they would like their file set up ahead of time. There are score lines in the drawing, meaning they are not meant to cut all the way through. They are there to make bending the acrylic easier!
If you wish to incorporate the use of a smartphone as a shot timer, a larger notch for the pivoting structure in the base will accommodate the placement of the phone.
Step 4: Laser Cutting
Choosing the colour and shape of your target is entirely up to you! I went with an opaque colour which makes it easy for the eye to look at. If you are putting a phone behind the target as a shot timer, a transparent colour will be more suitable so you can see what is on the screen of your phone. I used squares and circles because they are uniform shapes and offer the least amount of distraction from aiming.
After you have decided how the target will look, find what kind of file requirements your laser cutter wants. Check, edit, and send your file to them and set up an appointment to get your material cut. Check if your laser cutting connection has plastic you can purchase as well, as they may be able to do the entire job for you, saving you trouble of calibration issues.
I recommend cutting extra, just in case.
With your parts now laser cut, they are ready to be bent into shape!
Step 5: Getting Ready to Bend the Laser Cut Acrylic
Prepare a 2" tall block of wood to bend the acrylic around. the top surface should measure just under 3", give or take a 1/16". More narrow is safer. Ensure the edges of the block are square, and all sides are parallel. Fasten the block with double sided tape to the table of your workstation. We will call this the bending block.
Heating up acrylic will create offgas, which you shouldn't breath in a lot. Ensure your workspace is ventilated before proceeding.
Before turning on the acrylic bender, double sided tape a block of wood on it to act as a stop block, to ensure you are heating the same place on each of your pieces. Using the acrylic bender and the heat gun, you will heat up the acrylic to a bendable consistency. With using both appliances, this eliminates the need for the plastic to be flipped partway through heating.
You will be putting the score lines of the laser cut plastic facing down on the bending block. Depending on the shape of your target, you adhere additional stop blocks to the bending block to ensure they are being bent in a consistent fashion.
Step 6: Bending the Acrylic
Allow the acrylic bender to heat up, and position your heat gun about 8" away from the plastic. When the machine is nearing maximum heat, place your plastic on the heater and position the heat gun.
The distance you should hold the heat gun is dependent on how powerful your heat gun is. Heat the plastic for about 30 seconds, then pick up and wave it in the air. If the plastic does not bend easily with energetic arm movement, then continue to heat the plastic for another 15 seconds at the same distance.
Once the plastic sags with gravity and bends easily, center the plastic on the surface of your block of wood fastened to the table. This is where the score lines from the laser cut come into use. With the score lines facing down on the bending block, ensure there is equal space between the line and the block on either side.
Place a flat block of wood on top of the acrylic, to keep it steady and flat. Using another flat block of wood, press the exposed and now sagging tab of acrylic to the side of the wooden block firmly. Hold for 60 seconds.
Repeat for the other side.
If heated too fast, the acrylic will bubble. If heated too slow, too much of the plastic will be bendy.
Complete one piece at a time to catch errors.
Step 7: Making the Target Base
The wood that I purchased was slightly too thin to make a base, so I processed and glued the board back together so it was thicker. This meant I needed to purchase 2 feet of the board, in order to be able to use the machinery through every step.
Joint and Plane
Take your board of hardwood, and joint the most stable large side on the jointer.
Flip the freshly jointed side against the fence of the jointer, and joint the short side.
Next, plane the board in on the planer machine. This will ensure your board's large surfaces are parallel. If your board is over 1.25" thick, you are in luck, and you can plane the board precisely to 1.25". With 2' of this squared up hardwood, you can create 4 target bases.
If your board is like what I purchased, simply plane until the side has been completely processed. You will have enough wood for 2 target bases.
Joint the final untouched side on the jointer.
If your board was thinner than 1.25", then cut the board in half so you end up with 2, one foot long boards. Send the boards through the planer, to make the sides parallel and the same thickness.
Step 8: Making the Target Base -- Continued
At this stage, you should have two boards which are at least 1 foot long, about 6-5 inches wide, and at least .75 inch thick, with all sides parallel and square with each other.
Lay a sheet of wax paper to protect the surface of your workbench. Gather 8 C-clamps. Inspect the end grain direction of the boards, they should be placed in alternation so the board does not warp. Spread an ample amount of glue over the surface of one of the boards. Use a card or a spreader of some sort to evenly coat the entire surface. Place your second board on top of the glued board and clamp the four corners. Then clamp the four sides of the board. Leave to dry and cure overnight (12 hours)
Step 9: Making the Target Base -- Continued
Joint and Plane Again
Now with your wood glued up, scrape off the excess glue around the edges of the board. If there is too much glue to scrape easily, you can trim off the edge with the table saw or band saw.
--The front and back of the target bases are end grain, so be sure not to trim the board thinner than 5 inches wide (includes excess for final trimming, 4 inches is the final width).--
Process the board again so all the surfaces are square with each other: joint the broad side, then the short side, plane the opposite broad side, then joint the last remaining side.
Pass the board through the planer until it is 1.25 inches thick. This is the final thickness of the base.
Your board should now measure 1.25" x ~6-5" x ~12"
Since the grain of the wood flows from the front of the target base to the back, now comes time to divide the board into 5 inch segments.
On a band saw or table saw, use a cross cut sled to cut your board every 5 inches. Ensure the cuts are straight and square. If possible, keep two off cuts for later use.
Step 10: Making the Target Base -- Continued
At this stage, you have two 5" x 1.25" x ~6-5" blocks of wood, and a couple off cuts which are 1.25" x 5" x ~1".
Take your two larger blocks of wood to the table router, and mark off a half inch radius on the corner which will make the front of your base. Ensure you extend the lines across the edge, and that you are planning the radius for the end grain.
Due to the router table having a high likelihood of tearing out the wood, I have incorporated extra wood on either side of the base to be trimmed off as a final step.
When progressing with the cut, go in small increments, to produce the cleanest cut. Apply constant and even pressure on the cutter while making a pass. Move across at a smooth and steady pace - too fast and the cut will be rough, too slow and the wood will burn.
After this step, your block of wood starts to take shape!
The center of the radius is the center of the hole for the pivoting pin, or the 1/4" rod. Center punch the point before drilling on the drill press.
Drilling the pin hole at this stage will protect your work from tearout.
Step 11: Making the Target Base -- Continued
Mark the area to cut with a pencil.
In this step you will mill a cavity into the front of the target base, through the radius. To ensure you have no tearout on your cut, stick the offcut wood saved earlier to the front of the target. This will serve as a sacrificial piece to mill into.
The images in this step illustrate my clamping method to the bed of the mill. I double sided taped the main material to the bed of the mill, likewise the offcut to the front of the main material.
Mill -- Zeroing the machine
Utilizing a hand cranked mill is tedious work but can yield very satisfying results if used properly.
Place a piece of printer paper on top of your clamped work.
Using a large bit (0.75 - 1 inch) lower the head until the bit is almost pinching the paper, and lock the plunge. Pull the paper away, it should not rip but catch easily on the cutting bit.
Set the depth "setting" to zero. For me this involved unscrewing a knob until the marker reached the bottom.
Observe the marker of "zero" on your machine, and set your cutting depth to 0.75 inches. In my case I screwed the same knob until the marker reached the number, aligning it in the same way it aligned to the zero.
Your mill is now set up to precisely cut 0.75 inches down from the surface of your work.
Mill -- First Pass
With the large bit you will mill the majority of the cavity, leaving roughly 0.5 inches of material to the pencil border.
Do not cut more than half the bit's depth per pass.
Step 12: Making the Target Base -- Continued
Milling -- Edges and Corners
Fix a 0.25 inch radiused cutter to the chuck, and re-zero the tool.
Set the cut depth to 1 inch. This will be the final pass depth, so if you can lock the cut depth stop temporarily, namely with a set screw on the machine, doing so would be wise.
Position the cutter away from your pencil markings, and drill into the wood gradually until the hole created stops increasing in diameter. Carefully jog the cutter to corner of your pencil markings, and make note of the measurements of the position of the bed. For me, the knobs which move the mill bed had markings for 0.0004 of an inch. Without moving the position of the mill bed, gradually drill all the way down.
Lift the cutter up so it is plunged less than half of its full cutting depth, and finish your cut in the sacrificial offcut. Proceed with progressively shallower cuts, taking away less and less material each time. This maneuver will reduce tearout.
Repeat on the other side of the cavity, and complete the long edge with the same procedure.
Finish the remaining material with a flush cutter, overlapping each pass with at least half the cutting area.
Step 13: Making the Target Base -- the Finishing Touches
Trim the sides off your freshly milled target base, so the width is 4 inches overall and the cavity walls are 0.25 inches thick.
Filet the bottom edges of the target base by 0.25 of an inch with the router table. Again, cut in small intervals at a steady pace to prevent wood tearout or burning.
Use a pneumatic radial palm sander to sand the flat surfaces of the piece. Start with low grit sandpaper, and be thorough on each side.
The inside of the milled cavity might be rough and slightly uneven, so hand sand the inside surfaces and corners evenly. Take extra care on the exposed endgrain, even though time consuming, the endgrain can be sanded to a polish.
How complete of a sanding job you do will show up after a wood finish is applied, so take time at this stage. Start from a low grit of paper and finish on at least 600 grit.
Once your pieces are all sanded, they are ready for a finish to be applied! I chose linseed oil: it is not poisonous and offers waterproof characteristics, as well as being a light colour.
Step 14: Cut and Trim Pins
Cutting the Pin
Measure the 1/4 inch rod in the base, and tape off where you would like to cut, leaving about 1/32 inch of room for final fitting. The final dimensions of your wood target base may not be exactly 4 inches, and a flush fit of the pin to the base requires a custom fit.
Remove the rod from the target base and with a hacksaw. Repeat for the second target base.
Trimming and Fitting
File the ends of the rod flat and remove any sharp corners. Next, assemble the pin into the hole of the target base again.
Clamp the assembly in a table vice, and mask off the wood surrounding the pin with tape. Ensure the opposite side of the pin is flush with the wooden base. File the exposed rod end until also flush with the wood. Change the masking tape frequently to safeguard your wooden base.
Step 15: You're Done!
Assemble the acrylic target profile into the target base and slide in the pin, and you're done!
Sort of, if you wanted to have a self resetting target, there is one more step.
You might have guessed it, double sided tape a rare earth magnet in the middle of your target base, close to the pivoting point.
Double sided tape another magnet to the back of the acrylic profile, so the same polarity of the magnet is facing each other. This will cause the magnets to repel each other and force the target back up, after being struck by a projectile.
Now you're done!
Foam Down, my thesis project at Emily Carr University, was an uniquely challenging opportunity for me. Stemming from my passion for firearms, I had to explain my niche to an audience who saw my avocation in a sinister light.
I presented my excitement with airsoft action shooting sports. The fast paced target games proved to be fun for people who never tried before, and the safety rules proved that shooting guns can be enjoyed in a safe manner. Additionally the dedication towards the sport is apparent, showing its stable place in society.
Exposing the level of responsibility an individual is capable of exercising with dangerous tools, and the amount of fun that waits in becoming a marksman, led me to manifest this project into an opportunity to make target shooting sports more popular.
With my thesis project I increase accessibility to equipment and space by utilizing currently available indoor projectile launchers. I create a bridge for safety skills to be taught through shifting the target from a living being to an inert object. Lastly I challenge perception that guns have no place in pacifist hands, by perpetuating a fun and harmless game of marksmanship.
I would like to thank my professors, Keith, Zach, Maxe, and Scott for their input, patience, and support.
We have a be nice policy.
Please be positive and constructive.