Reinforcing interior plastics?

This is specifically about my 94 Supercoupe, but I'm sure it applies to a lot of other cars as well. The interior plastics on these cars are pretty brittle at this point. After 25+ years, mounting tabs and so on like to break.

I recently had to remove some dash trim to repair the car's odometer. In the process, one of the molded-in mounting bosses (on the back side of the trim, where it can't be seen) for a switch broke. I was able to find the pieces and glue it back together, but I'm sure it's more fragile than ever. 

I was thinking of blobbing on some hefty amounts of JB Weld or similar to reinforce the mounting area and give it a little more mass. Any reason I shouldn't, or anyone have a more effective technique?

Here's a picture of the area in question (the screw holes at each end of the oval opening):

Its made of ABS plastic.  ABS plastic melts with acetone.

Make a slurry

https://www.matterhackers.com/news/how-to-make-abs-juice-glue-and-slurry

We talked about plastic trim repair over on the Classic Motorsports site not too long ago. 

How about the plastic backers for the door cards.  They were once mostly made from compressed fiber board molded to shape, but some time in the early-mid 90's they started blow molding them from plastic.  I have a '95 Nissan with that type, I don't see a symbol indicating what it's made of, it's yellow, and it's starting to crumble.  I'm hoping it's not polypropylene, as it's nearly impossible to get anything to stick to it.

I have similar problems with the large plastic pieces in my Volvo 240. For the notorious door pockets I lined them with Kevlar using MGS resin. Stronger than the rest of the door now. For little bosses that break I have been able to wind Kevlar thread scraps around and soak in cyano acrilate. ABS needs to be roughed up a little for any epoxy resin to adhere well. including the MGS  

I did similar reinforcement with 2 part marine epoxy and fiberglass strands. Blob it on, add some fiber, repeat when dry. Has worked so far. 

This is likely not ABS but more than likely PP or TPO, a similar material to PP.  ABS fell out of favor for most automotive interior plastic trim before 1994.

ultraclyde (Forum Supporter) said:

I did similar reinforcement with 2 part marine epoxy and fiberglass strands. Blob it on, add some fiber, repeat when dry. Has worked so far. 

Came here to say this.  Epoxy FTW.  The Impala that I just sold, some of the slots that hold the door card push-clips had snapped off.  I mixed up some marine epoxy and mixed in a filler (in this case microfiber powder) to peanut butter consistency, and basically rebuilt the slots.  The next time I removed the door, some of the push clips broke, but the slots stayed strong.  Easy to replace the push clips.

I have done ABS with acetone, but it seems like the process of dissolving the plastic must wash away something.  Ever build a model of a car and use too much glue in a joint?  The plastic stays sticky and doesn't ever really regain its hardness.