I’ve been doing composites for a few years now and I always see people using those through the bag type vacuum connectors like this connector from Fibre Glast. I see them in the mid $20 to close to $40 range depending on the supplier and the fittings it comes with. Believe it or not, I’ve actually never used one in the few years I’ve been doing composites. When I got started it was an expense I didn’t want to pay. Now I’m just so used to doing it my way, I just never got one (or a few if you have a few parts going at once). They seem to work nice so I have nothing against them, just never adapted to using them. Below is a picture of the cheap and easy ways the I fill, or cover the ends of vacuum or infusion lines. On the left is a semi rigid vacuum line with some bleeder taped onto the end. The bleeder helps distribute the vacuum across the part and it keeps the bag from getting sucked into the end of the line. If you utilize this type of vacuum line with Stretchlon 200, without the end of the line covered or filled, there is a very high likely hood of the vacuum actually popping a hole in the bag as it get sucked into the vacuum line. The second is a more flexible, softer line that I use mostly for infusions. I will get a small scrap of flow net, roll it up, and stuff it into the end of the line. This keeps the vacuum pressure from sucking down and closing off the end of the line. I’ll also use this technique with the harder white lines on the vacuum side of an infusion setup. It would be a good idea to get some cheap spring loaded clamps to keep the vacuum lines against the mold flange as they can pull themselves off sometimes. You can mix and match the tubes with either the bleeder or net as you see fit for your purpose.
There you have it. Two cheap ways to finish vacuum lines when you are getting up and going. Try it out and let me know what you think, or let me know if I should pick up a few of those through bag connectors.