Infusion Q&A

A photo would definately help, but based on what I see now:

-split moulds / removable flanges might create problems, they always give me a headache. however, depending on detailing things can work. As long as it is airtight.

How to place the feed lines and vacuum lines: There are several possibilities:
The foam most likely will create a runner, or racetracking (or whatever you would like to call it).

If we assume you would not like to use infusion consumables (cost) then you might be able to feed along the foam, so any irregularities in flow are at the very beginning, when air pockets tend to disappear might they occur. The vacuum line can be on the opposite side, or even a single point diagonally across the feed point.

Things to watch for:
-use an infusion resin. (either polyester or epoxy)
-use a piece of mesh to feed the resin from spiral to laminate. (Airtech has some handy mesh pockets, which can be misused for that.)
-you might end up using heavier fabric, as you will lose thickness when infusing. This is one of those products that might benefit from a core layer of Polymat / Rovicore or similar, or even Soric.

(actually tuesday I will be infusing a large panel consisting from what I believe is a single layer of Polymat only.) Link to Polymat website: www.scott-fyfe.com and more specific: http://www.scott-fyfe.com/en/products/composite/ProductscompositepolymatHi-Flow.htm

 

Thanks Herman I will shoot a picture , I was planning and have in the past when I V -bagged these parts put the hole mold in a bag! I just made a large tube style bag wet out my fabric , placed it , slid it in a bag sealed it and applied a vac.,,

 

I am looking for advice about leak detectors, anybody have one they really like?

I bought an Amprobe ULD-300 ultrasonic leak detector years ago and never got it to work for the small leaks (say 1 mm Hg/minute vacuum drop), the ones that are hard to find. Maybe just some advice on how to get the most out of my unit, or a more appropriate unit. Thanks.

 

We use a Accutrak VPE great tool.

 

I also use Accutraks, which do their job.

This afternoon I will be testing a much cheaper unit for efficiency. I will be present with a cheap unit, another guy with an Accutrak. Whenever we find a leak we will have the opportunity to compare.

 

in the material dept, I have use peel ply a flow media, and a bag, with the use of flow media is polyester baby blanket necessary?
the part is 8' long and about 6" wide I am planning on suppling one of the 8' sides and drawing the other so the resin will only have to travel 6", any thoughts,,

I will take pictures

 

What you basicly need is perforated film, flow medium and a bag.

Place the perforated film over the laminate. No overlaps, or at least as little overlap as possible. Below it you can use peelply to get a course surface. However, I do not recommend it as a layer which enables you to get the flow medium off the part. Way too much effort to pull it off, even possible damage to the part.

Place the flow medium over the part, leaving 1" or so free from the vacuum side, and 2" or more over the flange on the resin side.

Place a strip of peelply or glass on the edge of the part on the vacuum side. (or if using peelply, overlap it over the vacuum flange).

Place your runners and bag, leak-check and infuse. Have fun!

 

Cheap unit did not work as expected, by the way. At least we have tried...

 

interesting that you let us all know ...

 

Thanks for the response; would that be the VPE or the VPE 1000? The VPE is price competetive with the Amprobe. The VPE 1000 is three times the green backs. But for the big bucks they do grant a 30 day money back trial period

 

Thanks for the response; again is the standard Accutrak VPE adequate or does it have to be the VPE 1000.

 

Who knows without trying,I take no ones word and put things to the test.

 

For me it is the Accutrak VPE now. Not the more expensive VPE 1000. Till now the VPE works good enough for me and my customers. I must admit I have never tried a VPE1000. Is the thing different (apart from a more sturdy design and nice headphones)

 

The HVAC guys are buying more of these leak detectors than us composite guys. They seem very devided in their opinion about Amprobe and others in their forums. I would say about 1/3 think they are Gods gift to mankind, 1/3 think they are a total waste of money never worked and never will (I probably fall in this group for now), and 1/3 have found situations where they help and situations where they are useless. Now the compication is that the admirers I found were mostly dealing with small leaks but at high pressure in hard lines. We are dealing with low vacuum pressures with mostly soft and probably dampening materials (tacky tape and bagging fim). It is going to be hard for me to dump another $350 US without some convert from Amprobe to Accutrak saying go for it. Here is a post from hvac-talk forum which may be of interest to our forum.

Most ultrasonics available to us only control either volume or sensitivity. But don't despair for most applications they will do quite well.

Today received the Accutrak VPE-1000. Has a Koss stereo headset with a monotone/stereo switch, a touch probe attachment, and air probe attachment. Has volume control and a sensitivity control. The probe can be adjusted for one sensitivity and the air sensitivity can be set at a different setting. It has a led display for the recording. This can be set by the mode switch to display continuous or peak hold. In continuous it displays the sound in real time in peak hold it will hold the highest level for 5 seconds.

Now I have a GoPro150 and a Amprobe ULD100 ultrasonics but just wanted something better. Well dug out that leaking solenoid stem for the upcoming seminar. Even with 200 psi the leak is more of a seep than a true leak. Neither 3 picked the seep up. Just not enough air disturbance. Covered the area with soap solution and even though the leak is visible the GoPro and the Amprobe barely moved one blip in the display window. The VPE-1000? Well it sounded like an M-16 in auto select going off in the headset. The LEDs displayed one quarter of the way up the window.

Now if the standard Accutrak VPE works that well, and it may, I am in. Did I remember to give you my VISA number

 

The unit I tested came with an ultrasonic reader (which is what we want) and an ultrasonic source. This is used to find leaks in car windows, etc. (toss the source in the car, then check the windows with the probe.)

The unit was able to detect the source, but nothing spectacular. Of course we also tested the Accutrak VPE to see if it could detect the ultrasonic source: Sounded like being inside a turbine engine. So this unit is much more sensitive. Also, with the VPE, you can stand in the boat, and wave the VPE around slowly to detect where approximately you still have a leak. Then you can get closer to the leak and narrow it down.

Big question stays: Is the VPE1000 more sensitive than the VPE?

I have an Airtech rep over this monday morning, I will ask him. (they sell both units)