Hi Gabriel Rojano
Thanks for your suggestions.
I'm sorry that I did not give you a full description of the problem I
encountered. There was no response in the multimetre when I measured the
resistance. Then I measured the block of epoxy directly, still I got the same
result. It seems that the epoxy itself is nonconductive at all. I checked the
package and confirmed that I was using the right epoxy-- CW2400 from
Chemtronics.
Can anyone advice me?

thanks,
Chen DF