ok, as i sed in my first post i do quite a lot of electronics as such i have bits lying around my house. i just came across some wire sleeving(thin insulating tubing) and the thought occured, what if i fill this with a comp such as BP? the resulting "fuse" would be totaly waterproof and as it has a fairly wide diameter about (3mm ID) i think it would burn quite slowly and reliably. the only down point would be that the tube is plastic and therefore would melt as the fuse burns, posibly causing problems. anyone got any thoughts on the idea?