Hi all,

I have been trying to pull vac on a panel in making and I can pull but not hold vac.

I started off with just a bag around the top face, edge taped, and after an hour or more of no joy put a second bag around the whole mould and first bag,

this still will not hold vac SO is it simply a case of poor bags (pin holes) or have I lost the plot!

I've found double bagging never works well,if you have a catch pot clamp off both side to make sure there is no leak from pot area,this to eliminate vacuum Loss you should be able to here a completely different tone when you have no leaks,good luck.

Ye ive clamped the mould side pipe and pot to vac is good.

only put a second bag on to prove if air was pulling from the mould its self.

air is definitely from the bag side but ad you can imagine ive been around and around it till ive now walked away for sanity reasons.lol

How are you storing your vac bags? 

Its simply folded up in a large carrier bag, will get some fresh tomorrow as live very close to EC.




I'm guessing ive damaged it by basically stuffing it in a big bag, no problem, learning as I go along.

It's possible. Vac bag is infuriating stuff, you could throw a pair of scissors at it and not damage it in the slightest, but fold it wrong or store it on its end and you'll have leaks galore. 

Haha, ive spent the best part of two days going over it so normality says it is in the bag somewhere.

Its no real problem as I'm new to all this so cutting my teeth.

the more issues I have the more I learn, step curve but very interesting all the same.

Yeh even so, you will likely still find that it's in the seal. Holes in the bag tend to make a hiss that you can hear. Sometimes you get a hole that doesn't make any audible noise, but in my experience it's usually in the bagging tape. Things like a single fibre can be virtually invisible but still cause a leak. It's a tedious task when you get a leak that you can't find in the first 10 minutes. 

Right ok,

I'm going to re tape today then and come at it fresh.

another thing to look out for is a strand of material going under your gum tape, this will give a slow leak like your describing. personally i find envelope bagging a lot more reliable.