I have a 1979 Cutlass.

the front end SMC plastic header has a crack on each corner on the top between the grill opening and the headlight.

What is the best technigue to fix this in the long run.

I had previously tried grinding it out and putting in some SMC resin. 10 years later it is cracked in the same place as before.

1. What is the best prep to do?

2. What is the best adhesive?

3. What is the best way to reinforce so it does not happen again?


concerned about good stuff to use. EPA rules have made stuff weak..


Thanks

Fred

 

I'm sure there are better modern chemicals to use, but I've modified some newer cars with this type of plastic. I used to use the Rigid Plastic repair compound, 2 part stuff. I did the repair similar to doing a fiberglass repair. Vee it out shallowly, mix some urethane repair compound, smear it on, cut and out on some fiberglass cloth, or screen, and bury it with more compound. When hardened, do the same on the backside, being sure to grind out the whole crack. You can always add extra 'glass on the backside for strength.

 

I have had some luck using the "hot stapler method" to reinforce plastic brakes. Heat a staple or small wire and insert across the crack or brake. Then resin on top. Body shops have the real tool and various shaped staples for this.

 

What Brand and part # of adhesive works best??????

 

If feasible drill a hole at the end of the crack before making the repair.

 

http://www.tcpglobal.com/DOM-XSMAR.html#.WN4rCqpMTcs

 

here is a photo of my header stripped to the SMC.

can someone advise me step by step?

Also what brand name products/materials to use.


I'd appreciate it.


fred

 

got some help from the Vette guys

West Systems Epoxy Resin and Hardener , and fill with Evercoat Vette Panel.

 

The problem isn't the patching material so much as it is caused by a designed-in high stress area. Since your first repair didn't (and couldn't) change the basic design of the part, the same stresses caused the same crack to return - and will likely do so again at some point in the future. This is also why every W-25 hood has stress cracks at the leading edges of the scoops.