Tap Plastic How-To Videos

[cfg83]

Hello -

I was looking up how to bend plastic for a possible Kamm-Back mod and I found this resource :

Tap Plastic How-To YouTube Videos :
http://www.youtube.com/profile?user=...cs&view=videos

This is the one I was looking at :

http://www.youtube.com/watch?v=ovqnI...e=channel_page

But, I don't want to shell out $65 for their strip heater.

I was thinking that if I had thin clear plastic, say sub-1/8", I could use a black metal rod *underneath* the plastic along the line I want to bend. Maybe the black metal rod would have a simple concave "focusing mirror half-tube" like they have in solar arrays to make the black metal hot. Add one hot summer day, and some patience, and I think I could warm the plastic enough to bend it. The key would be *thin* clear plastic. Thick enough to maintain rigidity at speed, but thin enough to bend at close/hot temperatures.

Question: Would it work? I am guessing it wouldn't get hot enough to bend, right?

CarloSW2

[Wilden]

I used the commercial versions of this tech in my DT class a few years ago. It's really simple so I think it would be a great idea for aero-modding.

As for your particular idea, I think it could work using a black metal strip. However, it will have to be really sunny to heat it to the correct temperature, plus it would take hours to heat up. With that in mind, it might be worth just going to a school and asking to use their equipment. I'm sure whoever is in charge of the technology classes would be interested in helping you out.

As for the thickness of the plastic, I'm not sure that 1/8th of an inch would be heavy enough stop vibrations at high speed unless it is secured very well. You also have to remember that at the point it is bent, the plastic is streatched and will therefore wont be as strong as it would be normally.

I'm not sure if there are any other methods of doing this without getting it done commercially so I can't help there. Good luck.

[TomO]

Typically I use a heat gun. When I had to bend a long length of plexiglass, I used a broom handle cut to the length of the piece and my heat gun set on high. I moved the gun back and forth along the bend point and let gravity pull the end of plexi down while I was heating it. Be sure to clamp the plexi/plastic to the broom handle or whatever you use so it doesn't move on you.

[dcb]

I saw that heat strip video and tried this, couple chunks of wood glued into a jig and put in the vice, just heat the plexiglass at the bend line with a propane torch and fold it over the top of the jig straight with another block of wood, then put the other end in and repeat. Make sure your jig is straight. The glare is horrible with this shiny plastic, so this is just display only, but looks pretty, and the plastic is like $1:

[captainslug]

Not quite as obvious but very effective solution: Iron (the kind you use for ironing shirts).
Seriously, it works. Drain it of all water and start it on a medium setting (around 150F). Then work up towards linen.

But unfortunately the plastics you would be using such a technique for are not terribly strong (acrylic specifically). If you want to thermoform a contoured shape that's durable you will probably want to go with slightly thicker ABS plastic. Then add a window made out of really thin polycarbonate

Let me know if you have any plastic-related questions. I've written a few introductory guides to plastics machining.
http://nerfhaven.com/forums/index.php?showtopic=8007