Help with inficon whisper ultrasonic leak detector

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#1

My Inficon Whisper leak detector arrived today and I still can’t find my leak. I am pulling 30in of vacuum and trying to do an infusion but I am loosing about 1in of vacuum every 10-15 minutes and the detector doesn’t find any leaks. The only thing I have found is when I put the headphones on I might head the tone of the static change a little but no beeps at all.

Any suggestions? I don’t believe I am doing anything wrong since you just turn it on and plug in the headphones.

Any help would be great, I am so close to having a perfect vacuum but don’t want to start the infusion until it is perfect so I don’t waste materials.

As usual, thanks everyone for the help.

#2

It can be hard to source a leak without actually taking the jump to infuse, the leak detectors have a place but I don’t find them reliable. We often just handle materials with caution and do our best to pull 28 merc and infuse, if we see air entering the part we trace the bubbles and tape off the area causing the leak. Maybe 1 in 100 parts has a void…

You’ll go crazy trying to make it perfect, there are to many variables which can sway an infusion from excellent to good to just straight up frustrating.

It is not abnormal to run a 10% wastage factor in this business…

#3

Check for cracks in the mold surface. If all else fails, do an envelop bag :).

#4

Thanks guys, Ill try to just infuse tonight and source the leak while infusing. I’ll try a couple infusions and if this leak detector doesn’t help then Ill just return it. I was really hoping this would be the solution to my leaking issues…

#5

Leak detectors does not find all leaks to 100%. They are very helpful but not the ultimate sollution.
To find the leaks while infusion is not a good idea, most times you will be crazy to find the leak. To stop getting air in you can take a lot of spray adhesive to close the leak.
Take a compound bagging film. When you close your vac line and shut down your pump there will be a cracking noise if there are any leaks.
Have you tried double bagging? Just for the first infusion with a new mould it is very good because possible small pores in the mould will be closed by infusion and your mould is tight.

#6

The leak(s) are so slow that I don’t hear any crackling. In the past I have definitely head the bag crackle when there is a leak. In this instance I am loosing about 1in of vacuum every 10-15 minutes so the bag doesn’t make any noise.

I think I may have an idea where the tiny leak is coming from because of the leak detector, should I get some spray adhesive and spray down the area and see if that stops the leak?

You have mentioned double bagging before but I am unfamiliar with this process, can you explain?

Is envelope bagging a good idea?

#7

If you use a stretchable bagging film you will not hear anny cracking noise if there are small leaks.
Double bagging means you seal the first bag on your mould lip and than you put the mould complete in a second bag.
90% of the people I know that use stretchable bagging films have problems with leaks.

#8

I have some Stretchlon film but am not using it this time because of all the issues I had with holes. This is the film I am using and it crackles if there is a leak:
http://www.easycomposites.co.uk/products/vacuum-bagging/vacuum-bagging-film.aspx

The issue is that my leak is so small that it doesn’t make any noise.

So to double bag it sounds like I need 2 vacuums or a T joint in my vacuum hose and the second bag is basically an envelope bag. My question then is why not just envelope bag the whole thing? If there is a leak in the first bag isn’t it kind of pointless anyway?

I am so close and really appreciate the help. You mentioned spray adhesive, should I give that a try on the area I suspect the leak to be coming from? I have tried covering it with bagging tape but the suspected leak just keeps moving around where I put the tape.

#9

You can spray the spray adhesive to the area where you suppose the leak.
Take a T joint to connect both bags to the pump. There is mo problem if there a small leaks in both bags.
The resin is infused by the ambient pressure. After infusion there is ambient pressur in the infused bag where the resin is. If you have only 300mpa in the second bag it is less than in the infused areas so no air will travel in the first bag.

#10

Use heavy bagging! Just pleats it with lots of pleats.

#11

That makes sense! Thank you for explaining that. Ill give double bagging a try! Now I need to take a run and pick up more bagging tape :).

#12

If you are using a new GRP mould, i would recommend strengthening it with another layer of fiberglass mat on its underside. GRP sometimes will leave microscopic pores on its surface especially if you didn’t use an adequate number of layers, both for stifness and impermeability to air. Another layer will seal the pores and do the job. One layer of fine “cobweb” mat as the last layer will also help.

#13

This is solid advice. I once laid up a mold with no gelcoat and I ran into this issue.

#14

How much did you pay for the Inficon whisper?

#15

Right around $200

#16

I think I may be returning this vacuum tester. The only leaks it could detect are ones I could hear on my own… We will see though.

I just tried double bagging and the infusion is in progress. I will post results on my other thread…

http://www.compositescentral.com/showthread.php?t=6837

#17

Well I am returning the tester, I am really disappointed but it can’t find any leaks. I was able to make it detect 1 leak but it was loud enough that I could hear it without the device. Did I just buy a cheap detector or something?

#18

I use this one, you have to build it by yourself and modify it. The micro is in the housing, you have to fix a cable to the microphone. It works as good than the most expensive ones.

http://www.elv.de/US-NF-Konverter,-Komplettbausatz/x.aspx/cid_74/detail_10/detail2_2060

#19

I have an Inficon and while it doesn’t find all leaks I find it handy since it seems to find most of them. Even for the ones I can hear it makes it very easy to locate them.

How are you searching for them? For me I’ve found it helpful to turn it on in a quiet environment. I also change the sensitivity frequently to find find the general location.

#20

Another thing, switch ge pump off when you use the leak detector.