See full version: How to Bend Sheet Acrylic or Plexiglass With Simple Tools
While you are applying even heat along the bend line, press gently upon the sheet of material you are bending. There will come a point when the material will move upward easily as it reaches a molten state. You should be able to feel this point evenly along the full width of the strip you are bending. It should not be softer on one side than on the other. more
You must wait until the moment when you feel the material "slump" as you have no way of measuring the heat. When you are applying upward pressure on the end of your acrylic, you will feel it start to move against your hand, then it will move very quickly. That free point when the material is able to move quickly is when you want to shape it against the jig. If you start trying to force it before it is fully softened, you will not get as even a bend, as it will be soft in some areas but not others along your bend line. [links]
Lay your plastic on your heat-safe work surface and place a scrap of strip wood over your plastic roughly 1/4 of an inch in front of where you want your bend to be. This will be somewhat determined by the thickness of your plastic, as thicker plastic will need a wider radius curve for most bends. Use a ruler to check that your sheet of plexiglass or plastic is held squarely clamped beneath your strip wood jig. The strip wood will restrict the application of heat (it will catch fire if you overheat the wood) and will prevent the plastic beneath it from becoming soft enough to bend.
The objective is to heat the plastic evenly along a line just in front of the straight edge of your clamped jig. To do so, pass your heat source at an even, slow speed along the line of plastic in front of the jig, keeping it far enough away that the heat source will not singe your wood jig.
Surprisingly enough, it can be bent at room temperature in a sheet metal bender, though it might also pick up marks from the machine. At that thickness it might crack since most benders would like to bend it to a tighter radius that it would like. A test with a scrap might be in order. more
Where the edges of the plastic pass over the heating element, the element should be bent downwards somewhat so the edges don't heat more than the rest of the plastic. If you're using a taut wire to create the heated line, this won't be as easily done. [links]
A heat gun will work, but you will not get sharp bends in material that thick. I believe that the production method used for thinner material is with a heated wire, and for thicker material it is a quartz heating element (like a laser printer fuser). I have a friend who had some good luck bending and welding using solvent. I believe he used chloroform, but several solvents should make it malleable. I would experiment with some clear PVC cleaning solvent and see if that softens it enough to be workable.
I have used the heat gun method for .125" material, and it makes a nice rolling radius, but depending on how sharp you need it, I doubt it will be satisfactory.
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The secret to the process is using a controlled heat source and spreading it out. In a word keep: it moving, keep it rotating. (OK, that was more than "a" word)
The key to the technique is constant movement - move the PVC pipe or the heat source back and forth over a 12" or so area and keep the pipe rotating all the while. After 3 or 4 minutes, the piece of pipe will start to sag. Keep it moving and rotating and begin bending it while rotating it - all the while keeping the heat on. [links]
PVC is a thermoplastic - which means that it becomes soft when heat is applied. You can use this little tidbit of knowledge to heat and re-form the pipe to a new shape without compromising its physical properties . if you are patient. more
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Each temperature at each location must not vary �5�F. This �5�F needs to be held throughout the heating, forming and cooling process. Thus, �5�F is the last component of the 10-10-5 rule.
Uniform Sheet Temperature here
THERMOFORMING: Determining the Right Temperature for Thermoforming
Determining the Right Temperature for Thermoforming Improving your thermoforming process is not a question of one heating element versus another, but rather the optimum element for the given application. Early thermoforming pioneers, namely Gaylord Brown and Robert Kostur, in 1954 concluded that it is the process, not the elements, that can make or break the successful (and cost-effective) forming of a quality part.
This, along with several other factors such as the type of machine, (rotary, shuttle, inline) the complexity of the part to be formed, sheet size, depth of draw, energy consumption, the thermoforming system�s process design and yes, the savvy of the operator, are critical factors. Nearly all heating approaches are good but the optimum (and recommended) heating system depends on the material and its end use.
The difference in temperature, or variance, must fall with what we call the 10-10-5 rule. The first 10 applies to the 10 locations on the sheet where temperature must be known: the four corners and center of both sides.
But heat is heat is heat, and the type of heat that should be used is dictated by numerous factors. There is no one type of heating element that is across-the-board better than another for all material applications.