I have a vintage toy and the components are contained in a polystyrene tray within a cardboard box. I need to remake the damaged polystyrene packaging.
How practical is it to make, at home, a mould of the original polystyrene packaging and use it to make a new tray? TIA.
If it is a thin plastic tray it sounds as if you are describing something that may have been vacuum formed. If that is the case you would need to have access to a vacuum forming machine of large enough size to reproduce your part. A vacuum forming mold could be made by using the original piece as part of a negative mold and casting a material into that. Two possiblities for casting materials would be an aluminium filled resin or ultracal 30 which is a type of cement/plaster. If you have woodworking skills a mold can also be made from scratch out of wood. Once you have a mold you would use this with your vacuum forming machine to make a plastic tray.
Richard wrote in article ...
It's not plastic it's very lightweight polystyrene foam. I think the term is Expanded Polystyrene (EPS).
Looking at it closely, it has a granular look. If you break it up small bit by small bit, it breaks up into small granular lumps.
I was wondering if you can buy polystyrene foam granules, put them in a mold and compress them into shape. Homemade of course.
Perhaps you can, but if heat is required then it looks difficult to do at home.
If it is, as you describe, expanded beads, then it will be considerable effort to make a new one. You will need the beads, a mold, and a heat source. Getting the beads may be the hardest part. You may be able to get a bead manufacturer to send you a sample, or if there is a plant in your area that makes coffee cups or the like, they might give you some. I did some prototypes many years ago and there was a plant close by. They were nice enough to keep me supplied through many prototypes. The beads come in different sizes for use in various wall thicknesses, and the blowing agent would leak out of the beads so you had to have a fresh supply. You might look into trying to repair what you have by carefully fitting a piece from other packaging and gluing in place.
Perhaps you could get expanded beads at you local DIY store. I think they may be used for decorative purposes (I'm not sure about this, but Xmas time is over, so this might be the right time to check).
Then you could perhaps try to glue them together using a suitable solvent. The solvent will plasticise the EPS and make the beads sticky, you can then "hand-mould" the beads into the desired form. After evaporation of the solvent the beads are glued together.
Acetone is a good solvent, so perhaps acetone/water mixtures will do.
Oliver
PS: When working with organic solvents the usual precautions apply: good ventilation, no open fire, you should be wearing protective gloves and goggles.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.