Plastic has indeed come a very long way if you look at it now, from the Bakelite days to the polymers that you are seeing around every day and people have become accustomed to it. Most people assume that all plastics are the same. With that in mind, they also think that plastics has a one size fits all plastic adhesive bonding.
The truth is, there are many variations of polymers out there, and each polymer has its unique characteristics. Most of the items that you see every day are made up of such material, and they break easily. No matter what the item is, a toy or a storage box, the first thing that would always come into your mind when it breaks is to fix it with a super glue.
While that might work, know that not all plastics are the same, so the best way to bond these will depend on the type of plastic. Some requires a solvent based bonding glue, while others an adhesive that is epoxy based. This why you need to find out what your item is made out of first before you start applying glue to it.
How to determine the type with the use of a recycling logo. Almost all people know what a recycling symbol is and how to determine one. In the logo, you can see three arrows which forms into a triangle. If you look closely, you will notice a number or code in the middle of the triangle. The code or number will tell you what group the item is, so you know which adhesive should you buy.
How to choose the right adhesive. There is a total of eight recycling codes, and these codes specify what material your product is made up of. Code one means PET or polyethylene terephthalate, two means HDPE or high in density polyethylene, three for PVC or polyvinyl chloride, four is LDPE or low density, five is polypropylene, six is polystyrene, and seven means other plastics.
After knowing what kind you have, the next thing you need to do is choose which adhesive suits your material best. Those that falls under one, two, three, four, and five categories are hard to glue. Check the label and look for the word polypropylene or polyethylene. There are certain things in category one that are impossible to bond.
PVC, which belongs in category three, is mostly used for plumbing. For this, you will need a solvent cement and primer, which are available in many home improvement and hardware stores. While items that belongs to category six are made from polystyrene. For this, you may use different options, cyanoacrylate, epoxy, or poly cement.
Category seven on the other hand are for all the other plastics that does not fit in any other categories, and that includes acrylic and polycarbonate. Epoxy works best for polycarbonate. To achieve the best result, acrylic would require a solvent adhesive specifically made for acrylics. Cyanoacrylate could also work, but that would depend on your project.
How to determine if no logo is present. There are instances wherein an item is not marked with a recycling code or logo. In circumstances like this, all you can do is research and guest. For hard plastics such as milk crate or bucket, it can either be polypropylene or polythylene. However, these are impossible to bond.