Hi, was wondering who of you use an ultrasonic leak finder.
Can you share your advice on its usefulness?
Brand/model?

Thanks!

I agree with everything said here about process - and the digital gauge will tell you a lot - especially about when you finally find the leak!  Generally this level of awesome bagging is an infusion or pre-preg (especially autoclave) thing - where leaks are more catastrophic.  Random note: probably half the hardest to locate leaks I have ever found in infusion bags are from cut edges of the flow mesh poking through the bag.  Plumbing and quick-connect fittings are a usual suspect too.  

My experience is that a leak detector / ultrasonic listening probe is a last resort... when you still can't find what is up - your drop test isn't good enough - and you have chased the bag edges down and checked all the penetrations.  Probably people making airplanes use one every day but as a boatbuilder it's been only a special occasion tool.  I have a beat up old Amprobe one with the earphones which is just a super-sensitive version of putting your ear to the bag - not a magic wand!  It is way easier to use one with earphones than just the LED lights.  Good over-the-ear earphones are very nice too.  

Using one is super annoying if you have a large or complex bag and sometimes you find the leak easily and sometimes you have to go back and re-bag the part anyway.  Moving and crinkling the bag is really noisy and small leaks are only easy to hear once you get very close.  Finding a leak in the middle of a huge bag is hard - finding one in the sealant tape or in plumbing is easier.  

I've heard about using a thermal camera to find leaks but haven't done it - I guess they show up cold.  Anybody do this before?