Greetings to all:
I cutout the broken rear screen on my 1999 Toyota Camry. The pinchweld has no scratches or rust and the cut down is within 1/32" to the pw. No priming of the glass is necessary, however I'm not sure if primer should be applied to the old urethane (in the pw) to reactivate it. What do you guys do when using U428 primerless urethane. Any help would be greatly appreciated. Thank you.
generally priming the pw urethane is necessary,, primer is used for painting the scratches you cause when removing the old urethane from the pw so you dont have a rust issue in the future,, whatever the manufacture directions say is the best course,, i dont use that urethane so i can say no more than that,,, hope this helps,,
First off unless you are holding the vehicle in shop over night , I wouldn't use the U428+ . Use Express,Advantage or O0ne If you are doing mobile . U428+ has from 5 - 16hrs SDAT that's the only reason I say this. We use Dow products but they have change the SDAT on the 428+ so we only use it for In Shop that stays over night or body shop stuff.
Now to answer your question, U428+,U418 and U418HV does not require preps or primers (pg8) glue is primer-less to GLASS ONLY, but you only have to use the U5404 primer on the bare spots or scratches and encapsulated parts. Thats what Dow's fancy training book (Fixed Automotive Installation Guide) says anyway. Now if its a new unpainted PW then you need the bare metal etch primer (U5201) (pg14).
This same info can be found on a PGW's site or Dow
