Home made vacuum bags

[Hornbeam]

I have just acquired a vacuum pump FOC and am looking to make a vacuum bag set up. Does anybody make their own bags and if so what material do they use.
I have seen some 500 micron PVC tent window material but was concerned it might be too unflexible
Any help appreciated.
Ian

 

[Droogs]

I use this stuff. Bought a roll t let me make bags of what ever size/shape I need:

https://www.amazon.co.uk/Polythene-Shee ... B00L29V8JA

 

[worn thumbs]

I use damp proof membrane.The next part of the jigsaw will be when you select a hose and the fitting to attach the bag to it.I use quick release hose fittings,but you may get away with using reinforced hose generously wrapped with mastic tape.

 

[Yojevol]

Have a look at my effort posted back in March:-
https://www.ukworkshop.co.uk/forums/a-new-homemade-vac-bag-t111335.html
The problem I have had is that the double sided sticky tape used for the seams has softened and now needs redoing. I will use plastic solvent glue which together with welding is another recognised method with PVC.
Looking forward to hearing how you get on.
Brian

 

[HOJ]

I did an experiment recently when I needed to vacuum some smaller sections, used one of the plastic shavings bag that I buy for my extractor, so only had one end to seal, worked a treat, and cheap.

David Charlesworth mentions in one of his books, welding pool liner with a domestic iron and newspaper, but no detail.

 

[Rorschach]

There is a tips from a shipwright video where he just uses a blowtorch to make a stem bag, might work for a vacuum bag too?

 

[Steve Maskery]

For a bag corrector I can recommend the ones sold by a company in Stoke-on-Trent. I forget their name, unfortunately but I'm sure they won't be hard to find.

Here you go:
https://www.easycomposites.co.uk/#!/vac ... tor_2.html

 

[worn thumbs]

Those connectors are very similar to mine,the difference being that mine have a bayonet fitting where the easycomposites units use a 1/4" bsp thread.

I'm a little puzzled by people using various welding and bonding techniques to tailor their bags.Mastic tape is a lot easier.Maybe its conditioning;a few years ago I worked with a cabinet maker who said that our bags worked as well as a "proper " vacuum bag.When I asked him what a "proper" vacuum bag was like,he described a hinged aluminium frame with a silicone membrane which I am sure we will have encountered from time to time.Nothing wrong with those but they are just one aspect of vacuum bagging and when you are faced with a 45 foot long 15 foot wide job that needs bagging,they aren't the answer.For the record,I have used the same polythene bag on a sheet of melamine faced chipboard to bond decorative ply to 14 doors using masking tape to seal the side that we used to insert and remove the doors.Two doors a day was easy and three just about possible.

 

[Steve Maskery]

Those connectors are very similar to mine,the difference being that mine have a bayonet fitting where the easycomposites units use a 1/4" bsp thread.

Yes and no. That link is just the valve part. There is also a QR fitting that screws to it. It's not really a bayonet, but it is one of those where you pull back an outer ring to release.
It works well.
Scroll further down that page to see the whole assembly.

 

[worn thumbs]

Since a picture is worth a thousand words,this is what my vac fittings look like.The quick release connector is on the other side.The threaded variety work quite well but after a few hundred jobs the threads in a softish alloy don't bite too well and my bayonet fittings just keep on working.