Okay, so I did a bit of experimenting with various plastics and PVC cement as well as CyanoAcrylate (Super Glue). Here's what these two can glue and what they can't:
PLASTIC TYPE ......... Recycling Number ................ dissolved by: PVC Cement .... CyanoAcrylate
...................................................................................................................................
PET/PETE ........................ #1 .................................................... NO .................. NO
HDPE .............................. #2 .................................................... NO .................. NO
V/PVC (vynil).................... #3 .................................................... YES ................. YES
LDPE/PELD ....................... #4 .................................................... NO .................. NO
PP (polypropylene) ............ #5 .................................................... NO .................. NO
PS (polystyrene) ............... #6 .................................................... YES ......... NO (maybe?)
(^ aka Styrofoam)
PC (polycarbonate) ............ #7 ............................................. NO (maybe?) ... YES (maybe?)
ABS ................................ #7 .................................................... YES ................ YES
Basically, what I found is that PVC cement works very very well on ABS and PS plastic, mostly because it contains a good amount of MEK and Acetone, both of which dissolve ABS and PS. With PC plastic, this wasn't so apparent, so I can't say if PVC cement works well on it (or at all). That said, Super Glue seems to work okay on PC plastic and seems to dissolve it mildly. In a pinch, Super Glue can also be used on PS and ABS, though it didn't seem as if the glue was dissolving the plastic that much, so it probably won't create as strong of a joint as PVC cement. But that doesn't really matter, since you don't want to over-apply Super Glue anyways, because then it won't cure.
So moral of all of this: if you are in a hurry, Super Glue will work with the plastics stated above. But if stronger joint is needed and drying time is not a problem, then PVC cement is the way to go.
Seen 3M tape hold trim on vehicles for 30+ years, I stand by my comment.
Provided it hasn't expired. I once bought a roll of 3M trim tape from an electronics surplus store and used it for a car's side molding, and once the weather hit 110F, the molding fell off. Changed the tape -- fell off again. Bought fresh 3M tape -- held the trim forever.
Sticks to EVERYTHING, including most plastics.
Fills in voids.
Doesn't shrink much. (if at all)
Waterproof.
Holds better than JB Weld, and doesn't get brittle like most epoxies.
Lasts "forever," unlike Ca glue.
Usually comes off quite easily with some heat & minor effort, even after years of use.
The only downside it that it's hard to sand or file, unless it has cured for several months.
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