A long time ago I bought a SDS Stormtrooper Stunt helmet which had some damage and was priced accordingly. It had two fairly large cracks under the left chin and some cracks inside the cavity where the mic tips attach. After removing the helmet from storage a couple of weeks ago I noticed that some areas have began to yellow over the years too. Thankfully the cracks haven't worsened but I feel it's now time to repair them and paint the helmet before it deteriorated further.
I believe the helmet is made of 2mm Styrene. What methods/materials can I use to repair the cracks? I thought of patching behind the crack with a piece of plastic or backing it with fiberglass, but I'm afraid of heat generated from this warping the plastic. Is there a type of suitable/flexible bondo that can be used on this kind of material too, to blend in the front face?
To the trooper experts, what kind of base colour paint is suitable for screen accurate troopers that will adhere to the material?
Old pic, the plastic around the crack has yellowed a lot since it was taken.
Haven't posted here for a long time either but I'm looking at rebooting my helmet collection, will be starting a new ESB Fett helmet soon too I hope )