Vac bag can't seal it.


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Interloper393
Interloper393
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Hi guys after some advice. I'm using all easy composites vac bag supply and pump.
I'm having major issues with bag leaks,  with the pump on its perfect but dosnt hold it once it's off,  and I'm not leaving the pump on for 2 hours lol.
Any way of checking and finding where the leaks are with any device. ? 
Also do you have to seal the hose onto the push connectors or will they be ok and airtight. ? 
Iv even tryed a flat bag and still leaks.. :s
I'm going to order the vac gauge,  anything other help would be grear lol..

Cheers
MarkMK
MarkMK
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Are you using the quick-release type couplings and a single vacuum line (you're not infusing)

If you're confident that you've made a good job of your pleats and general seal around the mould, then if could well be the through-bag connector set-up. If so, a bit more info on how you're installing this into the bag might help


scottracing
scottracing
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is your mould completely solid with no leaks? Even the smallest hole or crack will allow vac to escape.

Also check and re-check your bag, you should be able to hear any small leaks
Warren (Staff)
Warren (Staff)
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If you envelope bag it and it still leaks then you probably need to take a bit more care with the bagging.  It could be as simple as a few fibres bridging across the gum tape or a stray piece of fibreglass on the table or on the mould bursting the bag. 

Sanitise your bagging area as much as you can and touch the bag the minimum necessary.  With a bit of practice you should find you get the hang of it pretty quickly.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
rmaddock
rmaddock
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The two areas I have most trouble with are the inlet to the catch pot and the silicon through-bag connectors.

The catch pot I have has a plastic screw grommet. I feel I need to do that up very well indeed to get it to seal. Somebody suggested putting some copper pipe inside the plastic pipe to help.

The other usual suspect are the through-bag jobbies. As you push the pipe in, you can create the tiniest of pleats in the bagging film. They're enough to let the vacuum out (I know that's nonsense but I can't think a better way of expressing it). Make sure the film is really, really flat on the connector before putting tacky tape around to seal it.
Interloper393
Interloper393
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I'm not infusing yet but I have the through the bag connectors and just the ribbed end connectors the rubber hose goes into.
I won't be infusing until I can sort these issues,  just now I just using it to skin parts.
Warren (Staff)
Warren (Staff)
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A leak on the catch pot unless it is very bad should not effect the bag when doing a leak test as you should be clamping after the catch pot.

There is a bit of a knack  with the silicone connectors but basically you need to stretch the bagging film slightly as you press down on the gum tape to ensure there are no creases under the tape.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
MarkMK
MarkMK
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I've found that making a small 'doughnut' of bagging tape and placing this on top of the silicon connectors so that it sticks to the inside of the bag really helps with, firstly, making sure the connectors stay in the right position during bagging and secondly, reducing the amount of creasing when pushing in the hose (leading to a more reliable seal)

It sounds like the OP is using the screw in through-bag connectors, though.

I found these difficult to seal, initially, but found that allowing the slightly sharp threaded end to cut its own hole in the bag when connecting trough the bag helped (rather than trying to cut a hole in the bag

. Also, check that the connector has some form of sealant around the threaded section that goes into the knurled outer ring.

PTFE tape (suitable for gas fittings, not liquid) might be needed to make sure that it's air tight.
Interloper393
Interloper393
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Yes it's the screw type vac bag connector.
Can you buy vac leak testers and would that work for this? 
Finnluxury
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Buy a Micron meter. It will stop all your problems. basic vacuum gauge is too inaccurate. With Micron meter u can see live feed of the possible leaking. I only start infusing after I get vacuum of under 980microns. When typical vacuum gauge shows you a perfect vacuum, then micron meters just starting to life (shows 150.000microns). Then i run pump till I get it to 980 microns. When I bought this part, I never had any problems anymore. U cant hear tiny leaks even using the ultrasonic device. 

This is cheap versio and works like a dream:
https://www.trutechtools.com/BluVacMicro
GO

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