How would I reinforce cheap plastic toys cheaply?

Without looking at this question, the best answer would probably be to buy a new one, but that doesn't apply here.

Well a while back I bought G2 airsoft handgun for me and a couple of friends. Long story-short, they broke.

First the mag release broke, then the bottom of the mag itself, then finally an internal part. I reinforced the mag with tape, but I couldn't do much for the internals.

Recently, my friend decided to buy another one, a G13, which is a 1911 replica. Problem is that it comes from the same company, Galaxy, so I'm doubting the quality.

I haven't been able to get a definite answer, but some people who own the gun believe the internals are made of ABS plastic, which is better than the plastic in the G2. 



For the future, I would like to reinforce the internals with a thin layer of something?
Off the top of my head, I thought of enamel paint, shellac, and fiberglass resin. I'm not sure if a couple of thin coatings would do anything.

I've heard that friendly plastic is very durable as well. I could potentially use that to mold my own renewable internals. But I have no experience with that either, and doubt it could be molded into certain specifications.

Any ideas on how to increase durability?
I'm not expecting for it to last forever. I just need an extension on its really short lifetime (couple of months). 
Looking for a cost-friendly idea.