adhesives 101

[Stephen Sherman]

I think it would be a very good idea to identify the types of plastics 
before attempting any gluing, or even cleaning.

Some types of plastics can disintegrate when exposed to certain 
solvents, clear polycarbonate being one of those (e.g. model glue or any 
plastic "glue" that is a solvent based product and melts the two pieces 
together). Other glues just won't stick to some plastics (almost nothing 
sticks for long to polyethylene).

If you have a bunch of the two types of plastics, you can just 
experiment of course. But if you only have one of each item, I would be 
cautious. If the parts have the recycling triangles that will tell you 
which plastic they are. If not search online, there are some good basic 
lists for id'ing plastics. Once you know what you have, you can then 
find the right glue.  If you are lucky, your plastics will be a common 
type with many available glues (like PVC or ABS which are used in 
plastic plumbing pipe).  If not you will have to get more creative.

There is a product called Plast-Aid (or something close to that) which 
is a plastic glue and filler which I have used to repair plastic parts 
in the past. It sticks well to many plastics (but not all) and is fairly 
strong. A bit pricey, but good for what it does.

Good luck.