Hi all,

I need to design an array of wireless sensors, powered from a CR2032 coin battery. The sensors will be attached to a PCB which is approx. the same size as the battery. The variety of sensors (temperature, humidity, etc) and the quantity (maybe 1000 pcs) are not suitable to make me think to design a custom casing and make injection moulding, it will be too expensive. Rather, I think it will be best to put the entire PCB assembly in a potting compound, of a suitable shape (cylindrical most probably) and size. I have used in the past a compound from Robnor, this one:
http://ro.farnell.com/robnor/px439xs...02?ost=1664502
This compound is made by 2 components, epoxy resin and hardener composite, when mixed together it cures in a matter of approx. 10 minutes. After curing, it has a nice black surface finish, it is hard as a rock and it is not affected by temperature. It would be perfect for my needs, but there is one problem. Some sensors will require battery replacing once several years and once this compound is cured, that's it, you cannot remove it.
So my question is: can anyone recommend me a similar solution, a compound with approx same properties, but which can be removed/dissolved somehow, preferably by chemical means?
Thanks.