Tuesday, April 17, 2012

Precision Plasticard Cutting Made Easy


Finished Part

After writing last weeks post I realized that cutting those shapes may be a bit of a PITA.  So I thought I should show you all something I learned when robotics was my hobby.  I used to use the following technique on sheet metal with great success.

For this post I did a simple design of an antenna in eMachineshop CAD software as seen in the last post on Rhino Extra Armor.

Antenna Design Whole Sheet

Once you have a design laid out on paper, in this case a simple antenna, cutting it with any sort of precision can be problematic.  But if you use this technique, cutting out your plasticard designs doesn’t have to be hard at all.  You’ll need…
  • Your design printed with a water resistant ink/toner on standard printer paper.
  • Enough Plasticard sheet to handle your design
  • A glue stick
  • Cutting implements: Xacto knife, scissors, paper cutter, etc.
  • A container of water large enough to completely submerge your largest finished piece of plasticard.
Start with your design laid out as compactly as possible on the paper but leave room around the pieces (0.250” maybe) in case you make a cutting mistake.  If you share borders between multiple pieces and you make a cut on one piece wide, you’ve also just cut the adjacent piece short.  LEAVE ROOM!

Antenna Design cut downt

Next, cut the paper down to a size that is more manageable.

Individual Parts

From here you’ll cut out the individual paper pieces.

Glued to Plasticard

Once the individual paper pieces are cut, glue stick them to the plasticard.  You’re basically making a sticker here, so be thorough and try to cover the entire back surface of the paper.  Pay particular attention to the edges because if they don’t stick completely flat, it will make cutting them more difficult.

If your plasticard has straight edges, it’s perfectly fine to use them as an edge for the final part just like I did in the photo above.  Place the sticker and smooth it down.  Make sure there are no bubbles or raised edges.

Let the glue dry before you make any cuts or you may tear the paper while trying to cut it.

Parts Cut

The plasticard with the paper stickers above are nearly ready for the final step.  I just need to clean up the edges some, maybe.

Let Em Soak

This step is the the coolest because it’s so simple.  Just drop the parts in water to soften the glue back up.

Slide Off

Let them soak for 10 minutes and the paper just slides off!

Finished Pieces

Slide the paper off, swish the parts in the water again, and then dry them.  Now you have very precisely cut geometrically complex parts!

Back

In figuring out how far I could bend the pieces, I accidentally cracked one of the vertical bends and all of the mounting tabs on the stand section.  Turns out that plasticard doesn’t bend as well as sheet metal.

This forced me to add some reinforcement.  Looks like I have to work on the bending procedure next!

The great thing about this process is that it not only makes the cutting much easier, it is also very repeatable.  It’ll take some time, but you can end up with quite a few nearly identical parts using very few inexpensive tools, if that’s what you need.  No laser cutter needed!

5 comments:

  1. Nice work,thought of doing something similar when I make my Thunderhawks.I've also had the same problems bending styrene,although I tried to make a "trapjaw" for an Ork warboss,after 2 attempts and both snapping I've decided next time I'll try putting the styrene in straight from the tap (or faucet for you americans out there) hot water or blasting it with a hairdryer to warm it up first.

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    Replies
    1. Thanks, Oktane! Yeah, I just thought it wouldn't be necessary to heat it as it was a fairly thin sheet. Doing one bend is fine. But, to bend the other side I had to unbend the first and when the second was done I had to re-bend the first. that extra flexing caused the crack. Didn't happen on the second bend. Looks like if you make a bend, don't unbend or you'll fatigue and crack it.

      I'm sorta gearing up for a Storm Eagle conversion in a few months. But, that depends on when/if Legions arrives.

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  2. I use a very similar method when cutting out Plasticard. Although I am still trying to figure out the best way to cut very small plasticard pieces without getting a weird edge on it from the blade.

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    Replies
    1. Have you tried a Dremel? You can get very nice edges with one of those. It takes practice and a very steady hand, but it is possible. A secondary advantage to Dremels is that the edge is almoast completely smooth if you use a fine enough bit. You may have to pull off some excess platic, but the edge will be nice 9 times outa 10.

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  3. why not just print onto sticky or label paper to being with? even recycling older labels can work since minis are typically so...well,small!

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