Ideas on repairing cracked front spoiler

[86gt635]

I'm working on a m635 front spoiler and trying to figure out the best way to repair a crack before I paint it.
My first thought was to get some strong adhesive like JB Weld- plastic bonder and glue a piece to the back side of the crack and bevel the front side and fill with body filler.
Somebody else recommended plastic welding it. I've not done that before but wouldn't be against it if it would be stronger than a patch on the back side.
Thoughts?

[aegul44]

plastic weld it. Fill it with bond, sand, and paint. Google is a man's best friend.

[86gt635]

Yea, I've watched that video and about 30 others. Thanks for the input. All of them are showing plastic that was made in this century. We're dealing with 30 year old plastic.
Anybody have any hands on experience?

[ahlem]

You can get a plastic welder from Harbor Freight. You can troll the PNP for plastic parts that you can cut into strips to use for your welding material. It's trial and error so test out your plastic strips on a small area and get similar parts from a similar car and be sure to get them really clean. Work from the back side.

[Jordan]

The correct repair method starts with the type of plastic its made from.

Somewhere on the back should be some letters cast into it notating the type, from there you can decided how to repair.

[Wolfman]

bumper repair

3M Duramix

[MT325is]

http://www.zoro.com/3m-panel-bonding-adhesive-8115/i/G0242925/?gclid=CKGC_JGsv8oCFYM8aQodt7MHQA&gclsrc=aw.ds

i work in a body shop.. this is your best friend. make a thin v in both sides.. fill it in think on both sides. panel bond won't stick to shiny surface... so make sure you clean around the crack with 80grit sand paper. then set it on thick with a bump, and smooth it into the lip.. 12 hour cure time. then go to town sanding it, and making it look pretty.

we use panel bond to fix anything plastic. i even glued my sludge hammer handle to head and its lasted a year no issues.

panel bond is basically bonds, but glue. work it just like you would mud, as far as applying it and working it around the lip.

[Kershaw]

Yea, I've watched that video and about 30 others. Thanks for the input. All of them are showing plastic that was made in this century. We're dealing with 30 year old plastic.
Anybody have any hands on experience?

I plastic welded an ES spoiler that was cracked in about 6 different places. I used a soldering iron and pushed the plastic apart like a canyon, then scraped the plastic in and smoothed it out.

Worked great. 30 year old plastic is still plastic.

[86gt635]

So it turns out the spoiler is made from Elastogran, it's a thermoset plastic. It's not really a worthwhile endeavor to weld it, it just wouldn't be strong. I spoke with the national training manager for U-pol and they recommended using their 7061 product. It's a fiber filled filler specifically for plastic. They wanted me to drill holes, and use a mesh sheet on the back side for re-enforcement. The stuff isn't cheap, about $35 for 2 pounds. I took it upon myself to incorporate a molded piece of fiberglass for extra bracing. It's really secure and the U-pol filler worked great.