Plastic restoration - '75 heater control

[Hedgehog]

After a bit of looking I finally found an original heater control housing for my '75 CJ5 . As we all know that makes a 39 year old part, a 39 year old plastic part that isn't in perfect condition, but it is in decent shape. There are some cracks around the control holes that need some minor attention. The only real issue is it is a little warped or twisted.

People who know plastic have tricks. I'm looking for a trick or two to deal with the plastic being a little dry and how to remove the warp, possibly heat in hot water????????? It took a lot of digging to find one in this condition so breaking it wouldn't be a good thing.

 

[Hedgehog]

I appreciate you guys looking at this thread, but I wish I were more patient. After a Google search for straightening warped plastic it became obvious that my first thoughts were correct. To straighten plastic you need heat.

One of the posts by an airplane modeler with warped plastic problems found that forcing the parts into shape before heating was very effective. He would force the object into shape, heat in a micro wave until the plastic became moveable, then he cooled the part quickly locking the part in the desired shape. Other videos and forums essentially did the same thing with warnings about some plastics shrinking under heat making the process unacceptable for that type plastic.

So, I took the part and forced it straight by using screws to hold the part down. Then rather than using water, I used a heat gun to heat the whole part occasionally poking the plastic to see how much it moved. When the whole part got slightly rubbery It went under the faucet to cool. It worked! Naturally some areas moved more than I wanted so I heated just that area, shaped it by hand and dunked it in water to set the shape. I'm now pleased with the results.

I fear that this won't be good enough for a rough Jeep life. Now I'm planning on cutting sheet metal to shape which will fit in the back unseen, but making the part much stronger than the factory part. At least that's the plan.....

 

[jdarg]

Good stuff. Those housings are a PITA to find these days, aren't they?

 

[Hedgehog]

Hard to find is an understatement. The unit is still sitting on my counter and I'm tumbling it around in my hands working out a solution to several problems associated with it.

 

[harleydragon]

what about reinforcing it with fiberglass mat and rosin ??

 

[Hedgehog]

Yeah know. I've been into steel and welding lately so that's where my mind went. But fibergalss isn't a bad idea at all. It's strong, stable and easy to work into corners and such. Thanks for the idea.

 

[harleydragon]

I hear ya..I had a welding business for many years but as you said,glass is a lot easier to form sometimes..I built a basic little heating system for a willys one time out of fiberglass..made the shape I wanted out of cardboard,waxed it heavy,then glassed over it .after it dried I pulled the cardboard out