BMW LTW front lip retrofit questions

[Autotechnica]

BMW LTW front lip retrofit questions (pictures included) Post #1


How well does fiberglass bond to ABS plastic?

I've got a pair of fiberglass LTW lips (molded from original BMW motorsport LTW lips) that I want to stick onto my original M3 M-Tech front lip which is ABS plastic. I'm thinking of using "Bondo" fiberglass "cloth and resin" to bond it to the M3 front lip. How well will this hold? I'll probably put in a couple of self-tapping screws as well for extra security. The problem is, the lips are flat, there is no peice on the top for me to drill holes, so I must find a way to attach it to the lip. Any other suggestions would be appreciated.

Here's a picture, I just attached it using masking tape to show what it would look like installed.

Thanks,

Bryan

[Autotechnica]

close-up

[jllphan]

I think your method of adhering the two pieces is fine, i would be more concerned with the durability of the fiberglass lips. I'm sure an average day for you doesn't include high speed passes over speed bumps and seeing how close you can park to a curb, but if you had couple of beers or some girl's hand down your pants, it wouldn't be hard to f@#K those things up!!

[Autotechnica]

Originally posted by jllphan@Mar 30 2004, 05:44 PM
I think your method of adhering the two pieces is fine, i would be more concerned with the durability of the fiberglass lips.* I'm sure an average day for you doesn't include high speed passes over speed bumps and seeing how close you can park to a curb, but if you had couple of beers or some girl's hand down your pants, it wouldn't be hard to f@#K those things up!!

LOL, thanks for the reply

Actually, this is my second set of lips already. I cracked my first set hitting a really deep pot hole which was camouflaged by rain water. That was when my car's suspension was stock!

I've got a 1.5" drop in the front now, this should make things a lot more interesting. If it does crack again, I'm just going to cut the lip to half length and just leave them like that.

Hopefully using fiberglass to bond them together will work. I know lots of body shops use hard silicon to stick bumper peices together, do you think this is a better solution?

Thanks,

Bry

[jllphan]

Man, to be honest with you, i don't know enough about the differences in bonding properties to make a very accurate analysis between the two. I personally would go with the origional plan you mentioned, but i dont have any solid data to support such a decision.

[El Presidente]

If the fitment is good I would forgo the resin and use a strong adhesive (silicon or otherwsie) and the screws. Fiberglass tends to bond well to itself, but considering the plastic will be able to have more play in it, I would think then a fiberglass bond would be more prone to cracking/breaking or just coming undone in the event of a slight bumper movement that was more than the lip could handle.

I don't know if that makes and sense, but it makes sense in my head.

[Furious]

do it bry do it!