how to plastic repair

[thrstrmech]

got this pretty much almost toast fender...cleaned up the dirt and removed the tire rubber marks that were on the fender. so, here's what you need to get started: clamps, needle nose pliers and a heat gun...set to low heat and only takes about 30 seconds to heat the area up. use the needle nose pliers to hold the plastic where you want it. let it cool for a couple of minutes, then clamp it. the pics do not show the pliers, but you get the idea. removed a little bit of the damage material in order to get the plastic to align.

 

[Mope]

Also go with a soldering iron on the backside while clamped; it'll melt and fuse the cracks (some waste plastic as filler can be used too). Bondo or glaze the front/sand/paint and you're golden.

Hey, I recognize that HF heat gun

 

[thrstrmech]

yeap, done...filled with 3M Hysol, waiting to sand it after work today. Used the Hysol on the repair of this

 

[heagachongoose]

Be careful just melding the plastic back together with heat. The polymer will hold but it will be much weaker. For anything other than a stressed piece it will be fine though. The strength of a polymer comes from the entanglements of the elongated molecules. Once those bonds break there is no way to reproduce that strength unless you were to re-make the entire part. For a stressed piece I suggest hitting the back of the material with a heat gun, then pressing some wire mesh into the polymer over the break with plenty of overlap over each side. Go over both sides with epoxy, sand back and refinish the face. Viola. For most situations that will do the trick. .

 

[thrstrmech]

I use Hysol at work on flight control surfaces when needed, most of the repairs are sheet metal and bucking rivets, sometimes cherry max when called for. The combination of plastic welding and Hysol is pretty damn strong. The fairing stay shown above was repaired with two .032" sheet metal pieces, eight #6 screws and Hysol. That repair will stand up to normal use, however will bend or crack off in a crash just like an undamaged one.