Hoping for some help here.  My bagging is basically 50/50 ie one success to one fail. I'm making the bags using both the standard EC bag and the stretchy stuff depending on the part. I try to take a lot of care in making the bag and I feel I'm fairly precise with it but when do the vac drop test the needle will often pop up when I release the clamp.  Try as I can in terms of checking the tape and the bag, it's usually the case in a failure that all the pressing and checking will not find a leak, but there is one there of course.  Is there a device which can find a leak? I have tried everything including smoke to try to find a leak to no avail.

Ok thanks Matt. I have a bagged part at the moment with elastifilm and I can't find the leak.  Very frustrating so I'll have to remove the bag and the gum tape and use a normal bag with more pleats.