This is just a silly, but fun project to make something that looks like radioactive waste that has been spilled on a surface.
It’s basically fast-curing two part resin (I got mine at Poundland) and some photoluminescent powder (glow in the dark powder/pigment) from ebay.
There are two common types of glow in the dark powder. The older version based on copper doped zinc sulfide, and the much better modern version based on strontium aluminate which glows brighter for longer. Both types are readily available on ebay.
Making the custom glow in the dark spill (or other moulded shapes if desired) is as simple as mixing two part resin in a small disposable mixing pot (I use plastic shot glasses out of Poundland) and adding some of the pigment to it, then pouring it into a puddle on a suitable non-stick surface like silicone or polythene. Note that resin flows well, so be careful to make “puddles” on a flat surface to avoid ending up with slicks that find their way onto more permanent surfaces. Allow the resin to cure (have patience!) until it is fully solid and then release it from your surface/mould.
I prefer 5 minute curing resin for most applications, but you could use the one hour stuff for more working time. However, note that the longer it remains fluid, the further it is likely to creep, and it’s very sticky and messy stuff while still in liquid form.
