Shrink film is awesome. It's versatile, inexpensive, and a little goes a long way. Making shrink film jewelry is a fun activity you can do for yourself or with kids. It's extremely easy, quick to make, and a your creations can make some pretty awesome gifts. Did I mention it's not expensive? :-D
The pack of shrink film paper I bought was under $7 and came with 6 standard size clear sheets. For this Instructable I went through 1 1/2 sheets. I probably could have gotten away with only 1 sheet, but I wasn't being as careful with the measuring as I could have.
That said, with less than 1 1/2 sheets, I made over 15 rings. Some of course didn't work out (1/4" strips will shrivel up into a ball of mess) and others I accidently snapped (careful where you place your hole punches).
Now, the only science I teach is Technology & Engineering, but I do think using this material in the classroom for a variety of activities would be a lot of fun and very inexpensive (apparently you can use #6 plastic to recycle into shrink film pieces--just look for bottles, containers etc. that say "#6 plastic"). For a science class, you could use this material to discuss the processes the plastic goes through, what causes it to shrink, comparing heating methods, temperature and shrinkage, etc. And then the kids could take home some souveniers :-D
Step 1: Materials
-Sharpies, color pencil (depending on what type of plastic you use, you might need sand paper for the color to adhere), or paint pens.
-Rubber stamps/ink for decorating
-Cardboard/parchment paper/vellum (sheet for baking).
*Some brands have a plastic that can be printed on with InkJet Printers, and some have plastic that comes in different colors.
Step 2: Ring Size
Before you can start designing your ring, you need to figure out what size you want your ring to be. This means measuring your finger, using an online ring size converter to figure out the length etc. that you need, and then drawing it on your plastic.
I have a plastic ring mandrel that I used to find my ring finger size (8). Later I decided I wanted to make multiple sizes for this Instructable, but didn't have the mandrel with me, so I wrapped a strip of paper around the fingers I wanted to find the sizes of, marked off where the strip end met the rest of the paper, and then measured them against a ruler and against this ring converter chart.
A very important thing to remember during measurement is that depending on the type of plastic film you use, the plastic will shrink. The Grafix brand of plastic I'm using for this Instructable shrinks the plastic to 50% of it's original size. So whatever my ring size, I need to double it in order to get a ring that will fit my finger.
My ring finger size is an 8mm, so the circumference came out to 56.6mm (this is the length you want your strip to be after it shrinks). I used this online calculator to calculate my ring size circumference from mm to inches, which ended up being 2.22".
Again, the plastic I'm using shrinks by 50% when heated, so I want to double the length of plastic I'm using. I generally like a thinner band, so I'm going to make a few different rings with widths that are between 1/4"-1/2" after shrinking.
Another easy way to measure your fingers, wrap a clothing tape measure around your finger and then double the number.
Attached is a document I made for staying between the lines while decorating my rings. I just put it behind the shrink plastic and draw or stamp away :)
Step 3: Decorate!
Now you are ready to start decorating your rings! I used fine point Sharpies and did a bunch of Zentangle designs on mine.You can also use permanent ink and stencils, I couldn't find any of my small stencils so I just went with the markers. I also used my small paper punches to add star cutouts to my rings.
Step 4: Bake!
Using your oven, toaster oven, or embossing heat tool, heat up your plastic strips one at a time. Make sure you follow the instructions according to your particular brand, mine says bake at 300-350 for 2-3 minutes. In my toaster oven, the rings needed less than a minute to bake. Basically, you want to bake the plastic until it curls up and then flattens back out. I tried to make a short video of this process, but nothing wanted to cooperate.
Make sure you bake your rings on parchment paper, cardboard/cereal box, or vellum--nothing that will melt or burn and not on a bare cookie sheet surface. I just put a piece of parchment paper in my toaster oven.
Shrink film rings are not an exact science, so try a few test strips to find the best temperature and bake time for you.
When the strips flatten back out, quickly pull it from the oven and shape it around something round that is similar to your finger size, like a lipstick tube, ring mandrel, etc. The plastic cools crazy fast so you have to work as quick as possible.
In some cases, your edges might be a little sharp. It's recommended to use a nail file/buffer or sandpaper to smooth the edges out.
Step 5: Heat Guns
So I recently bought one of those nifty crafters heating/embossing guns. I used a 50% off coupon at A.C. Moore's and got it for like $10.
Using a heat gun WILL "bake" your shrink paper faster than in the oven, and the plastic seems to stay warmer longer which gives you a little more time to wrap and mold your ring. It also heats up super quick so you can re-warm your ring to fix any errors super fast.
The only problem I've had so far with the heat gun is that it blows the plastic all around while it shrinks, so having an extra pair of hands definitely helps.
The two rings above were done using a heat gun, literally took me under a minute and at least from the heart ring, easist circle yet.
Step 6: Fixing Mistakes
Getting the plastic wrapped correctly before it hardens can be tricky (see photos1-4). Thankfully, you can put your ring back in the oven for 20 or so seconds (keep you eye on it) to soften the plastic and gently straighten out your ring (photo #5)