Just found this on the net.
There are two approaches you can try for fixing warps in plastic. The first is to simply clamp the parts and adhere them with adhesive
. I prefer the liquid styrene cement, which actually fuses or welds the parts as opposed to adding an adhesive
to create the bond. Once so fused, they're nearly impossible to separate. Most of your alignment issues can be addressed this way.
Most warping issues for these models
come when you cut it to allow access for your RC components
. These are usually long cuts along the mid-line of the boat. It is common for the cut parts to see warping along the length, creating gaps in the seam that are unsightly and hard to address via the first method. For these, the solution is to mechanically force the part straight, then heat the plastic up to its Glass Transition temperature for a short time, then cool it off.
Polystyrene begins GT between 175-195° F (79-91 C) depending on its molecular weight, plasticizers, pigments and fillers. In order to straighten warped polystyrene parts, you need to get the plastic up to that temperature, allow it to settle in the proper shape, and then cool it back down again.
There are a number of ways to accomplish this. The safest one for small parts is to use hot water. Simply heat up a bowl of water in the microwave
to something around 200F, allow it to cool slightly and then dunk your part. Once the plastic has heated up, it should become more malleable and retain whatever shape it's put into. Dunk the part in cool water to lock in the new form and you're done! You can also use your oven, which allows for precise control of temperature in a larger format.
Most sub hulls are going to be much larger than your bowls or oven, so you're going to need to use something like a hair blow dryer
or, ideally, a heat gun
. This takes some practice, as it's easy to overheat the parts and get warping and distortion, or even burning if you're not careful. Never focus the heat gun
on one section for too long. Keep it moving at all times and use broad strokes so that you're heating up a large area. You'll see the part relax into the proper shape. Once it does, let it cool thoroughly before releasing your clamps and checking alignment. Repeat as often as necessary for a great fit.