: Chrome Trim



Mephy
02-22-05, 02:02 PM
Hello peeps... I have a 1998 Catera. Quick question. What's the best glue to use to glue the chrome trim back on? It's the chrome piece that goes on the rear lights. The little piece that goes from the left right on the trunk. Not the chrome on the brake lights, just the trunk part? Luckily, I saw it coming off before I lost it. I know Super Glue would hold it the best, but would that cloud up, or eat at the plastic on the tail light?

vogel81
02-22-05, 04:05 PM
From the factory they use double sided tape. You should be able to find some made by 3M or other manufacturers at your local auto parts store. Before applying the new tape you want to be sure to clean the old tape off with a good solvent.

Mephy
02-22-05, 04:58 PM
From the factory they use double sided tape. You should be able to find some made by 3M or other manufacturers at your local auto parts store. Before applying the new tape you want to be sure to clean the old tape off with a good solvent.



You sure they use tape? I find it hard to believe since the space that the trim goes in is only about 1/4 of an inch wide. That would be hard to do!

vogel81
02-23-05, 08:02 AM
I know 3M makes ¼” tape. I am not completely sure that Cadillac does use tape behind the strip, but I looked at my strip and it appears that there is double sided tape behind it. I am not sure, but in any case, it may be easier to just super glue the strip back in if it hasn’t completely come off.

Mephy
02-23-05, 02:30 PM
Ya, I'm leaning towards super glue, but I don't want it to ruin my tail light OR the trim. Super Glue LOVES to eat plastic, or at least turn it white and fog it up. Thanks for the input!

stevehogan
02-23-05, 07:46 PM
Superglue (or any cyanoacrylate adhesive) is very likely to craze the lens, causing it to ultimately crack. :annoyed: If you can't find the very thin 3M tape adhesive (should be able to get it at an auto body supply shop - it's not the usual white foam stuff that you see at the hardware store but rather a very thin material, typically black) you might use an epoxy that is designed to bond to plastic. Ace Hardware carries a product called "Plastic Bonding Epoxy" (or something like that). It's not the "standard" epoxy, but one formulated to stick stuff to plastic. Be careful, though as it you can use too much and squeeze it all over the lens. :banghead:

Hope this helps

Mephy
02-24-05, 11:15 AM
Superglue (or any cyanoacrylate adhesive) is very likely to craze the lens, causing it to ultimately crack. :annoyed: If you can't find the very thin 3M tape adhesive (should be able to get it at an auto body supply shop - it's not the usual white foam stuff that you see at the hardware store but rather a very thin material, typically black) you might use an epoxy that is designed to bond to plastic. Ace Hardware carries a product called "Plastic Bonding Epoxy" (or something like that). It's not the "standard" epoxy, but one formulated to stick stuff to plastic. Be careful, though as it you can use too much and squeeze it all over the lens. :banghead:

Hope this helps

Thanks for the suggestions. From what I remember about epoxys, don't they pretty much melt the 2 pieces of plastic so they bond together? I'm actually thinking of getting some kind of 3M Scotch Grip Plastic Adhesive, like # 4475 or something like that. :nono: What a pain!! Thanks everyone.

stevehogan
02-26-05, 09:20 AM
Epoxys don't actually "melt" the plastic - it's more complex than that. Generally, it takes a solvent-based adhesive to actually "melt" the plastic, assuming tht it is a thermoplastic (such as a taillight lens) and not a thermoset plastic (as used in many electrical parts), or some sort of material that actually reacts with the chemistry of the plastic (such as CAs like Superglue). To bond well to plastics, the molecules of the adhesive need to be structured such that they can "fit" into the microscopic spaces between the molecules of something very "smooth" like a plastic (particularly tough with things like nylon or Teflon) or between the crystaline grain of something like a metal. That's why they always tell you to "rough up" the surfaces for "better adhesion." The trick is to combine the right kind of molecules to grab the surfaces into some sort of chemical mix that will cure (harden) when you want it to cure (and not sooner or later). It gets more complicated when there is any sort of gap to fill i.e. when the parts don't fit tightly together. Then the adhesive itself must have very good molecule-to-molecule strength or the adhesive itself will become a weak point. Epoxies excel in large gap situations, but are not so good on very smooth surfaces. That's where the special formulations (such as the Ace Hardware stuff I mentioned earlier) come into play.

If you really want to do a superior job of bonding metal to plastic, Loctite and Devcon each make families of two-part structural adhesives (methacrylate-based) especially designed for that purpose. These are a little more difficult to find. Of course, any liquid adhesive takes a little bit of care in appliacation, lest you make a mess. That's why the car makers use the double-backed tapes in their various forms (with integrated adhesives designed for the purpose at hand). They don't do as good of a job, but they keep the less-talented folks in the assembly process from messing up too badly.

Now, aren't you glad you asked? :yup:

stevehogan
02-26-05, 09:26 AM
One more thing I forgot to mention:deadhorse

CA adhesives, such as Superglue, generally fail after a short time when exposed to moisture, such as you will encounter in car washes and rainstorms. That's why (with certain exceptions such as the bonding of rubber-based materials) they are generally not used for exterior applications.


Steve