Most standard super glues can also be applied to plastics with good results. You’ll find a wide selection of plastic glues, super glues, and similar craft adhesives at your local hardware store or home improvement center. Be sure to pick up enough glue to tackle your project without running out.
Wear rubber gloves when working with plastic glue to prevent the adhesive from getting on your skin.
It may help to tape the broken piece down or set a weighted object on top of it to hold it steady. A C-clamp can come in handy for holding together oddly-shaped items.
Some types of glue may take up to 24 hours to cure completely. Follow the drying instructions outlined on the product’s packaging to see what additional drying tips the manufacturer recommends.
Use just enough glue to hold the pieces together. It’s possible for the heat from the soldering iron to react with certain types of adhesive and cause discoloration. When you’re dealing with a crack, split, or clean break, melting down the plastic may be the only way to rejoin it.
Don’t set your soldering iron higher than about 400–500 °F (204–260 °C). Fusing plastics doesn’t require nearly as much heat as fusing metals. Before you get started, clean the tip of the iron with a damp sponge to remove any residue from past projects. [7] X Research source
Whenever possible, solder the pieces together along the backside so that the resulting seam will be less visible from the front. For your own safety, always don protective eyewear while operating a soldering iron. It’s also a good idea to wear a respirator or breathing mask and work in a well-ventilated area to avoid inhaling noxious fumes from the plastic.
Ideally, the scrap piece should be the same type of plastic as the rest of the item. However, you should be able to fuse mismatched plastics successfully in most cases. [10] X Research source
For an even smoother finish, use basic sandpaper to wear away larger inconsistencies like bumps and ridges, then switch to an ultra-fine variety (300-grit or higher) to even out the surface.
It’s critical that whatever container you use be made of a material like glass or ceramic. You want it to dissolve the plastic you’ll be using for, not the cup that’s holding it. Acetone is a hazardous liquid that gives off powerful fumes, so be sure to work somewhere with good ventilation. [12] X Research source
For a more natural looking repair job, try to find plastic in the same color as the item you’re repairing. Avoid touching the acetone. It can cause mild irritation if it comes into contact with your skin. [14] X Research source
Cutting or breaking the plastic into smaller pieces may help speed things along. The more surface area it has, the faster the acetone will act on it. [16] X Research source The slurry should have a smooth, creamy consistency and be free of lumps or chunks before you attempt to use it to weld other pieces together.
It’s okay if there are traces amounts of acetone left in the container. It will quickly evaporate on its own.
If possible, apply the slurry to the back or underside of the piece so it won’t be as noticeable. Use as much of the plastic as you need to successfully seal up the damaged area (you’ll probably end up with quite a bit left over).
The new joint will be about 95% as strong as the original plastic. [20] X Research source
