How to identify the type of plastic

Question

I'm wondering if there's a practical method of recognizing what kind of plastic a something is made of. This is a recurring issue I face when trying to fix/glue/work-with plastic stuff around the house.

More specifically, I was trying to fix the connection of a garden hose reel. I thought that the black, carbon-like, hard plastic was ABS and used some ABS-compatible glue, but the bonding came off almost immediately after it was put under pressure. So, before I try again, I'd like a way to identify the material and use the right kind of products for it.

Answer 1

Most products you purchase will have the information on the label. If no information is provided you can look for a marking similar to the following that will help you identify the type of plastic it was made with.

ABS does not have a symbol, but is often marked >ABS<.

In your case, I'd look around the base of the hose reel you should be able to find it. If not consult the manufacturers website.

Answer 2

After 30+ years in the plastics industry, my tried and true method is to take a scraping of the plastic piece and burn it, extinguish the flame and smell the smoke.

Polyolefins will catch fire, smell like candles (a paraffin based plastic); PVC won't usually ignite, smells like chlorine and will burn your nose - BE CAREFUL; ABS has a sweet smell and burns with a very black smoke; styrene isn't as sweet and burns black also; nylon takes more flame to ignite and has a smell like burning hair and also burns your nose; epoxies smell like a burned out electric motor.

Answer 3

There are numerous guides for attempting to identify the type of a plastic.

But when it comes to adhesives it appears that you can cover all your bases with just three:

1. Cyanoacrylate ("superglue").
2. Primer (a.k.a. "activator"). Before using a glue like #1 on polycarbonate, polystyrene, polyethylene, polypropylene, PVC, or PTFE: you basically need to dissolve the surfaces to be bonded. PVC primer is widely available and cheap in the plumbing section. All other commercial primers appear to be similar combinations of solvents. In a pinch, acetone might do the trick.
3. Acrylic cement. Apparently ABS is just too different from the other plastics, and so it needs its own solvent and binders. However, some of these are so aggressive that they seem to work on every plastic too: For example, when in doubt, or when all else fails, I tend to use SCIGRIP 16, which is nominally an acrylic cement.

Note that this is for cheap household repairs. If you really want to fix plastic, proper heat welding or carefully-matched chemical or epoxy welding is the way to go.