Tag Archives: cuff

72: Bending Acrylic

This post resulted from Rebecca of Hugs are Fun asking if a thin piece of acrylic could be bent for a bracelet.  Challenge taken, and the answer is yes, it definitely works!

cuffs

My first thought was to try to boil the plastic to heating, like they do to make toothbrush bracelets.  This seemed potentially messy (or scalding) so when I saw that Harbor Freight had low level heat guns for $15, I picked one up.  (Any excuse to get more tools, right?)

Bendycrylic (17 of 42)I happen to have a never used bracelet mandrel in the back of my supply closet, when I had big dreams of making wire wrapped cuffs.  I dusted that baby off and it was perfect for this project.  The biggest problem is that this thing weighs a ton. So it has to be a stationary mandrel – it’s not something I could flip around too easily and it might disfigure the warm acrylic if I laid it directly on it.

The materials:

For the test, I used 1/8th (3mm) acrylic. We had some extra leftover 3mm florescent acrylics we used for Ingress badges, and I figured if were were making cuffs, let’s go 80’s all the way!  I cut the blanks using the leather cuff designs from Week 3.  I made them 6.25 inches long, since it seemed all metal cuff blanks (that you can buy to stamp on) are 6 inches long.

bracelet blanks
bracelet blanks

The process:

We weren’t sure how drippy or gooey the acrylic would get, and how hard it would be to handle, so we laid the mandrel flat, propped up on a couple potholders.  We set the acrylic perpendicular to the mandrel, so it could drape around it as it melted.

Big heavy mandrel!

Heated acrylic
Heated acrylic
You can see where the bend wasn't quite right
You can see where the bend wasn’t quite right

This setup was very cumbersome, and took both Ryan and I to make it work.  The acrylic didn’t stay in place on the mandrel (it slipped off because of the taper), so it had to be held.  While Ryan held it, I had the heat gun.  I started at the low level, and slowly it heated up.  Because we had to continually hold it (and we like our fingers), the heat wasn’t even.  It created some lumpy / flat sides, and we had to flip the entire mandrel in order to curve the open part correctly, which required more heating.

Look, ma, no gloves!
Look, ma, no gloves! (we didn’t get any photos of the second and third cuffs – we had to work fast to keep the heat!  To fast to remember to stop and aim the camera 🙂
Parchment paper heating.
Parchment paper heating.

Second go round, I set the mandrel upright, and it stayed nicely on the sturdy base.  I heated the blank laid flat on a piece of parchment paper, sweeping back and forth slowly to make it even.  When it was pliable, we picked up the whole parchment paper and wrapped the bracelet around the upright mandrel.  It worked well, but the ends did lose some heat.  They weren’t pliable enough to wrap around and make the perfect cuff oval.  I didn’t think to reheat the acrylic when I got a little resistance, but instead pushed harder, and part of the intricate swirl design cracked.  Lesson learned.

The circle shows the crack - the florescent material made it hard to photograph!
The circle shows the crack – the florescent material made it hard to photograph!
The center row of beads is not in the center - it meltd before the outsides got fully pliable, and then cooled closer to one edge.
The center row of beads is not in the center – it meltd before the outsides got fully pliable, and then cooled closer to one edge.

The third bracelet, the triple strand, was heated up slowly on parchment (even slower than the swirly one, because the thin middle strand heated up faster than the outside ones and started to warp.  Keep that in mind for future designs!)  When pliable, we shaped in around the mandrel.  Instead of pushing the ends down, Ryan held the bracelet and I gave each one a shot of heat and pressed.  The resulting cuff was amazingly perfect.

In order from worst (right) to best (left)!
In order from worst (right) to best (left)!

Tips and Lessons learned:

– Go longer than 6.25 inches.  I think I would try 6.5 next time.  The cuff opening was a little too big for me.

– It didn’t smell awful, but it is warm plastic – work in a ventilated area.

– Pliable plastic is hot, but not instant burn hot (says the girl who started molding it with her bare hands, whoops).  That said, pot holders and work gloves did come in handy.

– You can leave fingerprints in pliable plastic.  That’s a novel way to sign your work 🙂

– Make sure your designs have even line thickness, or take special care not to melt thin areas before the thick ones are fully heated.

– The cheapie heat gun worked great, no need for anything fancy.

Squish.
Squish.

– The acrylic is flexible, but not overly so.  I was able to touch the open ends of a cuff together without cracking or stress.  Anything beyond that broke the swirly cuff.  Something to take into account with designs as well.

It broke on the thinnest part.
It broke on the thinnest part.

I’d love to hear what you think!  Is there a market for these?