Heating up new nose headlights' lenses?

[Frank818]

The new nose headlights' lenses do not conform totally on the headlights' fiberglass surround, especially at the bottom outside. Maybe up to half an inch down I need to press on the lense.

I tried heating up the lense with a heat gun, it changes the transparency to more opaque while it's hot and comes back to transparent once cold. But I couldn't change the shape of that lexan or plexiglass or acrylic.

On YouTube they do it with a heatgun for the thinner parts.
https://www.youtube.com/watch?v=XpjGzlPIMqQ

So quick and easy, but it doesn't work for me. For that guy the plexiglass didn't come opaque. Mine did. And it took him a few sec to heat it up and bend it, it took me quite more than that and yes it was softer but couldn't retain the shape I was trying to give it.

[UnhipPopano]

I do not think that F5 used an acrylic plastic for the headlights. Acrylic would not only yellow in time, but would easily scratch up. The better guess is that they are made of Polycarbonate. Polycarbonate has a melting point of around 300 degrees, verses 200 for acrylic. The vid identified two problems with using a heat gun to do the job. It showed the effect of hot spots creating small bubbles and making the spot opaque. It also showed that if the plastic sets in stress, it becomes very brittle and will easily crack.

If you want to change the shape, you may be able to create a form for each piece and using your kitchen oven.

[Frank818]

Well my heatgun on lowest setting heats up to 150C (300F) and the polycarb Tg is 149 (297F). Not melting but semi-solid so you can bend it.

Then I'll rely on the 3M VHB tape to hold the form in place on the car.

[UnhipPopano]

The idea is that you heat it up until it changes shape on its own. Then when it cools, it will not be stressed. Be very careful not to overheat.