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Massimiliano
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Hi, was wondering who of you use an ultrasonic leak finder.
Can you share your advice on its usefulness?
Brand/model?
Thanks!
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Massimiliano
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Group: Forum Members
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+xHi, was wondering who of you use an ultrasonic leak finder. Can you share your advice on its usefulness? Brand/model? Thanks! I assume no one is using it? 🤔
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beliblisk
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Did you try digital absolute vacuum gauge? I find it really useful and over time it actually teaches you what kind of leak equates to different looses in vacuum.
Now i get sub 10mbar every time (sub 20mbar inside few min on bigger parts).
Small bag punctures are really rare (once you start covering infusion spiral and ends of infusion mesh with some tape).
I think its a must have item.
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oekmont
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I do prefer a digital gauge over a leak finder, too. If you are careful with your bag the leak is always at the sealing tape. And a digital gauge helps finding them a lot quicker and much more reliable than an ultrasonic leak finder.
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Massimiliano
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Group: Forum Members
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+xI do prefer a digital gauge over a leak finder, too. If you are careful with your bag the leak is always at the sealing tape. And a digital gauge helps finding them a lot quicker and much more reliable than an ultrasonic leak finder. Thank you all for the replies. I do have a digital gauge, but still not have enough experience to match the vacuum loss to a specific issue...
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beliblisk
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Just be methodical. Hers few tips: -Clean working space helps (i vacuum my small workshop befor applying vacuum bag)
-i apply perimiter seal tape prior to anything else so it seats on clean sourface(add pleats later on)
-seal silicone inserts from the inside as well
-watch for stray fibers
-make big enough bag
-double tape on pleats
-take your time(you will get better and quicker soon)
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Chris Rogers
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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?
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Hanaldo
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Good tips above, but just to add one:
Put a lot of effort into pressing down your bagging tape.
I think until you realise how tiny a leak has to be to cause problems, you won't realise how much effort it can take to get the bagging tape to seal. This is especially true if you are using a firmer or older tape, there are many different grades and some are much easier to get a seal with than others. But even the soft ones can often take a lot of pressing to fully close a tiny air passage, and if you try to take a shortcut and not work every inch of your seal, then there's a good chance you will miss the leak. My thumb nails will often feel bruised for days after an infusion, that's how much effort it can take.
It is finicky stuff, sometimes you can throw the bag on and barely put any effort in and pull a 100% vacuum straught away, and sometimes you will work and rework every inch of the seal 2 or 3 times and still have a leak, and it's only on the 4th time around while your thumbs are screaming for mercy that you magically press the right spot and the leak is gone. Following beliblisks tips will improve your chances of getting a full seal without the pain, but if you've done all that and still have a leak, you're better off spending your time working the bagging tape than you are searching around with a leak detector.
To answer the original question - I've got a Bacharach Tru Pointe 2100. It was hideously expensive, it works well. It has probably paid for itself by now, but I do this every day and have been for 8 years. I would estimate it has probably found 1 in every 25 leaks that I have had in that time. For the hobbyist, those aren't great numbers. Ultrasonic leak detectors are ok, but I would consider them luxury equipment for the professional rather than essential equipment for everybody. Nail your technique and put time and effort into the bagging tape, and 24/25 times you won't need the expensive gear.
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Massimiliano
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Group: Forum Members
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+xGood tips above, but just to add one: Put a lot of effort into pressing down your bagging tape. I think until you realise how tiny a leak has to be to cause problems, you won't realise how much effort it can take to get the bagging tape to seal. This is especially true if you are using a firmer or older tape, there are many different grades and some are much easier to get a seal with than others. But even the soft ones can often take a lot of pressing to fully close a tiny air passage, and if you try to take a shortcut and not work every inch of your seal, then there's a good chance you will miss the leak. My thumb nails will often feel bruised for days after an infusion, that's how much effort it can take. It is finicky stuff, sometimes you can throw the bag on and barely put any effort in and pull a 100% vacuum straught away, and sometimes you will work and rework every inch of the seal 2 or 3 times and still have a leak, and it's only on the 4th time around while your thumbs are screaming for mercy that you magically press the right spot and the leak is gone. Following beliblisks tips will improve your chances of getting a full seal without the pain, but if you've done all that and still have a leak, you're better off spending your time working the bagging tape than you are searching around with a leak detector. To answer the original question - I've got a Bacharach Tru Pointe 2100. It was hideously expensive, it works well. It has probably paid for itself by now, but I do this every day and have been for 8 years. I would estimate it has probably found 1 in every 25 leaks that I have had in that time. For the hobbyist, those aren't great numbers. Ultrasonic leak detectors are ok, but I would consider them luxury equipment for the professional rather than essential equipment for everybody. Nail your technique and put time and effort into the bagging tape, and 24/25 times you won't need the expensive gear. Thank you all for the usual diamonds I receive from you! I will put more attention to the digital gauge. I made an infusion last week and despite pressing the seal many times I was not able to pass the drop test. I then borrowed an ultrasonic leak finder from a friend and was still not able to spot the leak! Long story short, I trashed the bag and the seal, used new seal and new film... drop test passed! I know to cover the spiral with peel ply, I have learnt today to cover the edges of the infusion mesh too... thanks!
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Sustainablecatamarandesign...
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Hanaldo, any particular brands/grades of bagging tape you particularly recommend using or avoiding?
Dave
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