Hello,

First of all rotational moulding isn't something we have a vast experience of ourselves.

In terms of resin sticking, you can avoid that through the use of a suitable release agent. However with most release agents by thier definition resisting resins, I'm not sure how well that would help you getting an even coating if you use a really effective release agent such as a chemical release agent.

A silicone mould would be relatively simple to make.  Silicone is fractionally heavier than water (exact figures on datasheet) so by weight you would use roughly 1.1kg per litre volume.  You can calculate the volume of the box easy enough then subtract the volume of the part to get the volume of silicone needed. You can do that mathematically or practically through water displacement if its a complicated shape.

In terms of resins, Our Fast-CastPolyurethane Casting Resin has a short pot life of 3 minutes 30 seconds.  Not having a lot of experience with rotational casting, i'm not sure if this is enough time for your needs???

In terms of quantity of resin, it depends on your desired wall thickness. If you know the rough surface area, you can calculate a rough volume needed for your desired wall thickness and by the same method with the silicone, the weight of casting resin. I would recommend using a bit more than necessary at first until you get the hang of it. Id expect its better to have a part too thick and heavy rather than with voids of no resin or too thin and weak.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant