One big problem that people will face with bag seals, is that if U r using too Slippery releasing agent. Then the bag seal wont hold. Example with Flex-Z series releasing agents. if U r using number 3, its easy to get bag to seal. but 4, 5, 6 are hard. Those are just too slippery and it wont hold the vacuum.

I'll seal up every conector,  putty the bag connector and keep trying... the bag tape ain't cheap lol.

Looks like a good tool but, in reality, the OP's issue appears to be achieving a full vacuum when bagging and there doesn't appear to be any problems with identifying the fact that the bag is leaking

If the through-bag connector itself is air-tight and sealed, then it'll likely just be a case of refining the bagging technique. If there is any doubt over the metal through-bag connectors, then it might be an idea to just try a silicone one, which might prove to be a bit more straightforward in terms of sealing. This might help eliminate one potential issue, at least

If looking to use vacuum pressure to aid consolidation on a skinning job, I'd also be awake to the possibility of the fabric being pulled and crimped by the bag, especially if there are quite a few angles to the part. It might work out okay, but it sounds like getting the fabric to lay=down neatly could be difficult to control

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

Yes it's the screw type vac bag connector.
Can you buy vac leak testers and would that work for this? 

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.

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

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.

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.

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