Introduction: Invisibility Shield
So, you want to make an invisibility shield, eh? Of course you do! Who wouldn't want the ability to become invisible? Watch the video above to see the fun you can have with an invisibility shield made from a sheet of Lenticular Lens. Are you excited yet?!
Enter this raffle to win my invisibility shield (the raffle benefits a charity fighting hunger), or get started making your own by ordering your supplies:
- [Quantity 1] Lenticular Lens Sheet: 40 x 28 inches (711 x 1016 mm)
- [Quantity 2] Liquid Optically Clear Adhesive: 50 ml, low viscosity, you need 2 vials
- [Quantity 1] Polycarbonate Sheet: 1/8 x 48 x 48 inches (3.2 x 1219 mm)
- [Quantity 1] UV Lamp: 100 W
- [Variable Quantity] Optically Clear Adhesive Sheets: Any size is OK, you need 4 sheets
- [Quantity 1] Rubber Roller: Optional, but highly recommended for the glue process
- [Quantity 1] Film Removal Stickers: Optional, but recommended for working with OCA sheets
Step 1: Cut the Polycarbonate
First you need to cut your shield and handles out of your piece of polycarbonate, following my PDF drawing (below). You can use a CNC table router if you have access to one, or you can use a hand-held router, reciprocating saw, bandsaw, circular saw, handsaw, or even a well trained beaver with sharp teeth who likes a good challenge.
Special Note for CNC or Hand-Held Routers: It's fine to leave the internal corners rounded. Mine were, and the results were great! The little radius was barely visible when compared to the overall size of the part. I used an 1/8 inch diameter O-Flute bit from Onsrud, it cuts sooo goood.
Step 2: Bend the Tabs
Next, bend your tabs back. The exact angle is not important, just bend them far enough so that you can't see them when you're looking at the front of your shield.
What's that? You've never bent plastic before? With most plastics it's pretty difficult, but you're in luck because you're using polycarbonate! This plastic is really easy to bend and you don't need to heat it or do anything special, just bend it! While you're bending, you might feel afraid it's going to snap.... but don't worry, it won't snap because polycarbonate is special like that. It's the bendable plastic of your dreams!
I bent my tabs using a bending machine called a finger brake, but you can use a shop vise or whatever you have available to you. I even bent one of the tabs just using my bare hands during my prototyping process. I just tapped into some leftover teenage angst and pushed with all my strength and it bent! I'm not a super strong person. As you can see in the photos my body was mostly designed for typing, so you can probably do it too.
Step 3: Glue the Lenticular Lens to Your Shield
Remove the oddly satisfying plastic film from the front of your shield, and set it on some boxes or whatever you have nearby to raise it off the floor.
Make sure your shield and lenticular sheet are clean of dust before you proceed. I wiped mine with a microfiber cloth sprayed with alcohol, but you can also use a paper towel.
Next, take your two 50 ml vials of Optically Clear Adhesive, and spread the glue on your polycarbonate in the pattern you see in my photos. The pattern helps prevent air bubbles. To get all the glue to come out, you'll need to push the plunger all the way into the vial using a pen or stick or whatever's handy.
Now, carefully place your lenticular sheet onto the glue. The lenticular sheet has a smooth side and a side with ridges. Make sure to place the smooth side against the glue, so the ridges are facing away from the shield.
Use your hands (or a roller, if you purchased one) to push down HARD on the lenticular sheet and force the glue to spread out and fill the entire air gap between the polycarbonate and the lenticular sheet. If you see an air bubble in the glue, press down hard and squeeze and push that bubble to the edge of the sheet where it will pop and disappear. Special Note: The roller makes this much, much easier because it concentrates your forces to produce a higher pressure. I hope you bought the roller! I did the first one without the roller and my muscles were really sore the next day.
The glue gets everywhere so when you're done, carefully clean any glue mess from your shield using a paper towel or microfiber cloth soaked in alcohol.
Step 4: Cure the Adhesive With UV Light
Hang your UV light above your shield. I used a backdrop stand and some spring clamps, but you could use a broom handle suspended across two stools, or whatever you have handy. The UV light should be about 10 - 20 inches (25 - 50 cm) from your shield. If your light is too close, the light won't spread to the edges of your shield.. but if it's too far, the light won't be concentrated enough to cure the glue.
Turn on the light and let the adhesive cure for 24 hours. Depending on how powerful your light is, you might find that some adhesive towards the edges of your shield is not hardened even after 24 hours. If so, move your light above the uncured section and wait another 24 hours.
Finally, remove the last layer of protective film, and clean any last bits of uncured glue with a microfiber cloth or paper towel soaked in alcohol.
Step 5: Attach the Handles
Cut your Optically Clear Adhesive (OCA) sheets so that they are about 1/4 inch (6 mm) less than the width of your tab. This will make it easier to align.
Your OCA sheets have not one, not two, but THREE glorious protective films. Remove the first two layers (the widest and second-widest) of protective film to expose one side of the adhesive. Now stick the OCA sheet to the tabs and press down hard to get a good bond.
Next you need to remove the final protective film from the OCA sheet. This one is super hard to get with your fingernails. You can do it by carefully using a utility knife or hobby knife to peel it back, but be prepared for a little frustration. Instead, if you bought the optional OCA film removal stickers, stick one to a corner of the film and press it down hard with your fingernail to get a good bond, then slowly peel back the film and you'll see how amazingly easy this step is with the right tool (the film removal stickers).
Finally, remove the protective film from your polycarbonate handles and stick them on to your tabs. Press down super hard with your fingers to make sure the adhesive sheets bond well to the polycarbonate.
Step 6: Become Invisible!
Have fun becoming invisible. Remember, with great power comes great responsibility.
This magical illusion is pretty easy to use, as long as you follow this one weird trick: The background really needs to have strong horizontal stripes. It could be stairs, aluminum siding, bricks, a chair rail on a wall somewhere, a dark TV on top of a single-color stand, really anything that has clearly visible horizontal stripes.
This is an entry in the
First Time Author Contest