Forming ABS plastic
 

First off, what about Mom's kitchen tools?
I get asked about his quite a bit- everybody has a kitchen stove, and some have wondered: Can this thing help me make parts?

The answer: NO. Kitchen stoves are designed for the heating and cooking of things that are safe to consume and SMELL, i.e., Steak Tri-tips, chocolate cakes, etc. that being said, I've used my trusty Amana for worse...

Heating PLASTIC in your home immediately sets up DANGEROUS conditions. MOST plastics "out-gas" when heated, releasing volatile fumes, corrosive agents, not the building blocks of life. Sometimes, the mixtures can be deadly! A lot of plastics (thermosets) just won't melt or get soft, they'll char and go to flames first.

Like most Thermoplastics, once MELTED, ABS will puddle and bubble, and then spectacularly burst into sticky flames. Yes, Mom would be mad.
So DON'T DO THIS yourself. Consider this information on how I play with fire, nothing more.
Most of what you need to know about ABS:
http://en.wikipedia.org/wiki/Abs_plastic
Buried in this info (actually in a link) is the "heat deflection temp" for ABS plastic. It's 185 degrees Fahrenheit. that means, at a uniform temp of 185, it can be deflected. Fancy way of saying "bent".

But you don't really want to fully heat a sheet, just bend it to your will.

http://www.air-sharp.com/make_a_colorado_part020.JPG
This is an electric bending strip. Made of a teflon/fiberglass mesh, with a heating element woven into it.
http://www.interstateplastics.com has these in different lengths, this is a 24".

http://www.air-sharp.com/make_a_colorado_part021.JPG
Making STRAIGHT bends is much easier if there is a groove routed into the backside of the bend. It just takes a bit longer to heat through without, and a bit more care is required to get the bend positioned correctly, and be straight.

Depending thickness, time will vary for getting the plastic to the right temp. Note the digital timer. By putting it in count-up mode for the first bend, I determined that 2.5 minutes were needed for full heating. Then I just set up a count-down for the next parts, and was able to carry the timer while I did other small tasks.
ABOVE ALL, you don't want to become distracted and forget about plastic in-process.


http://www.air-sharp.com/make_a_colorado_part025.JPG
The finished bend.


http://www.air-sharp.com/make_a_colorado_part047.JPG
No, these weren't airsoft parts...

Next: "Hey Honey, here's a Macy's $50 gift certificate I forgot to give you last Christmas!"


Damn, that was easy, I won't see HER for four or five hours.
Upside, the house will air-out if needed. Downside: A gift certificate only opens a door, figure it being 25% of the shopping trip's bounty.

So she's off, the mutts are locked outside, and the stove in the kitchen just got done making me some frozen meatpies from Costco. Rather than shut it off, I turned down the temp to 320.

I know, only 185 does the job, but it would take much longer to soften the part. The trick is to get the ambient temp around it a bit higher, so it all softens uniformly.

My example is a drum, or Trommel, magazine for my treasured Marui Thommy:
http://www.air-sharp.com/Thommy_mag_motorized_0044.JPG
The drums were made in 50- and 100-round versions. Both were more deadly to the shooter than the shootee, they jammed like crazy.

Rather than fight a strip of 3mm ABS into a band, I'll give it a shot of BTU's, and wrap it around something round, like this stack of MDF disks:
http://www.air-sharp.com/Thommy_mag_motorized_0016.JPG

The strip, 20" x 1.70" was laid lengthwise in the oven on lower rack, and the oven light snapped on.
I only wanted the material SOFT, not MELTED! The first experimental parts looked more like egg noodles than drum bands.

So I watched as the strip "relaxed" and then flipped it over, and closed the door for a few more seconds.
http://www.air-sharp.com/Thommy_mag_motorized_0018.JPG
Then, it was quickly snatched out and slapped around the form. Grabbing from the oven was done with bare hands, as the contact time was low, and heat doesn't "transfer" from ABS quickly, but holding it against the form (after a slight stretch to make sure it laid flat) required some oven mitts.
By the fourth try, I had it down to a process.

http://www.air-sharp.com/Thommy_mag_motorized_0017.JPG
Finished bands, after cooling. even though I needed bands of varying diameters, I only used the one form, as ABS is pliable enough to be final-shaped in or out at gluing.

http://www.air-sharp.com/Thommy_mag_motorized_0040.JPG

QUESTIONS?

i salvaged heating elements off a little toaster over... i'm planning on doing a plastic heater out of them... just needs to clear my currents projects!;)

Safety First! Be careful with that stuff, it's made of (nearly pure) grief.

Well done. Informative yet written clearly for us laymen to understand your process.

wow thats impressive..

I've used a Thermoplastic, medical grade, and they are literally softened with hot, not quite boiling, water.

THey make things easier to mold and shape when you can handle it with bare hands the entire time. :D

Been meaning to get some to play with.
Unfortunately, it comes in WHITE, and doesn't look all that paintable.

The sample I got was black. My friend is an occupational therapist that works with people with hand problems. She primarily uses it to make braces and supports.

Do you know the trade name for the stuff?

I'll check when I get back from vacation. The polyformo stuff is primarily white with some that come in beige. the stuff I got was black.

You see a lot of the stuff used in movie props and animatronics.

Sliding off-topic for some fun (I gave myself the day off, you should too)...
On YouTube, there's a series of Videos, where a robotic toy bear flies an RC plane. The onboard cam catches him working the controls, looking around:
YouTube - R/C airplane with Pilot teddy bear HDV video
This is one of the COOLEST homebuilt things I've seen. Imagine the fabrication that went into this guy. An airsoft gun seems pretty simple now, huh?

I asked a friend of mine who used to work with sports medicine splints and she said that the black stuff is rare since most people work with the white stuff. Anyway, here's a link to the stuff she used to work with here. It's called "Orthoplast II". Hope it helps.

Dang 'spensive! I get a 4' x 8' sheet of 6mm ABS for about $80 at
www.interstateoplastics.com

The black is used for sign making.

odd. my occupational therapist friend is always making new hand braces for herself with left over scraps she has from patients. she gave me an 8"x11" sized sheet to sample making my own wrist brace/guard.

I do find the white stuff to be a lot thinner though.

I had no idea ABS was so versatile until reading your threads. Thanks!