LCD Cover

Step 2 Bending The Plexiglass

I talked to a few glass stores in town, but I couldn't find anybody who would bend plexi. I did some research online and found that some people had successfully used a heat gun and very gentle pressure, so I decided to try it. After borrowing a heat gun from my roommate's girlfriend's mother, I set up a crude heating and bending mold with a piece of wood and a metal level. I applied the heat gun to the gap between the block and level, and very, very carefully, the plexiglass started to soften and melt. As the acrylic starts to melt, the pressure from the block will start bending it. I needed to tack down the level, because it had a tendancy to scoot to the right as the bend progressed. Eventually, you will need to apply pressure to the left edge towards the level. Once the plexi is bent at 90 degrees, turn off the heat gun and let it cool right here before moving it. I moved the first edge before letting it cool, and it flexed back to about an 80 degree angle.

You can see in the last image my progress after bending two of the sides.

Comments

[SWERDNA]

Hi out there from darkest Africa! I am a total novice at manipulating Plexiglass - I have this concept of 'rippling' Plexiglass like a flag in the wind frozen in time - is a Heatgun the only method or are there chemical solutions to achieve this effect?

SWERDNA

[Dr. dB]

Chemicals would tend to badly "frost" and/or "craze" the surface while seriously damaging the molecular structure of the polymer - which CAN be used as "special effects", but that doesn't sound like what you're looking for.
To "ripple" a sizeable sheet without scarring the surface, you might be better off with the "drape" method: pre-build a (heat-resistant) "rippling" framework to lay it on, then heat the entire thing in a oven until the plastic "sags" into the form. Just be VERY careful of the heat setting(s) as plexi can FLASH into flames when it reaches the right (wrong!) temperature. (Just keep an eye on it - if it starts to "bubble", you've over-shot - it's already many degrees HOTTER than needed for bending, but will still be a little COOLER than the "flash" point, so you can prevent a fire...)
Alternately, depending on the thickness of plastic you want, there are several excellent 'ibles on building your own vacuum-forming jig...

[SWERDNA]

Thank you Dr dB! (Hoping you are a real-live person and not a robot)

I will try your method - I have a small piece of corrugated iron roof sheet with a nice ripple that should do the trick - I'll be standing by with fire extinguisher

You alluded to chemicals - I am an artist and stumbling into sculpture and accumulating knowledge as I go along - what chemicals will badly frost and/or craze the Plexi?!?! This sounds cool

Yours
Swerdna

[aaron]

will a hair dryer be hot enough to soften the acrylic?

[Tommyhzy]

LOL haha a HAIR DRYER XD

[Xamith]

I think that means no.

[Tommyhzy]

If you notice, each of those 3 comments were posted ~30 days from each other. Also, that means NONONONONONONO NO WAY! HAIR DRYERS are far too inaccurate, and the heat produced is not nearly enough to heat the acrylic before it cools again. Unless you happen to build sort of a tunnel for the hot air so it is recycled throughout, but that takes WAY more time to build than the time it might take to borrow a heat gun from a friendly neighbour...

[Xamith]

lol