Making a Vacuum Bag

[Tenson]

Can I please get some recommendations of where to source bits of making a vacuum bag in the UK?

I need vinyl sheet and vinyl cement.

I actually have some 'Plastic Weld' which I guess might do the job but it is very thin and fast to evaporate so I'm not convinced I could paint a strip and then apply it along the seam of a bag.

Finally I need some hose connectors. I have a vacuum pump I got from eBay and the thread for the vacuum inlet measures 16.5mm I'm not sure what thread this is? I guess as the pump is made in China it is not going to be BST but it looks closest to 3/8" BST?

[mekanik]

Hi Tenson
I have done some bagging and just used some clear plastic sheeting that i had for a slip membrane to go over my floor insulation before i laid a screed, just sealed the ends with gaffer tape. you could just secure your pipe direct to the pump adapter and fix with jubilee clip.
What is the bag for? veneering flat work ? vacuum infusion ?
Have a look here
http://www.easycomposites.co.uk/#!/s...arter-kit.html
This will give you an idea of the materials that are available, this site is not the cheapest so shop around when you've seen what you want, the proper bags cost an absolute fortune for what they are, i bought some that are used for vacuum storing bed linen/clothes ect seems to be the same stuff as the expensive type and the have an adapter built in.
Regards
Mike

[Tenson]

This is for veneering. I will use it on a regular basis so I want to make it well.

[mekanik]

The Vacuum Storage Bags i mentioned have a seal on one end, just looked at mine and it's 900x1200. I did post a picture on the forum for someone that was asking what type of glue to use in veneering that showed the setup i was using, unfortunately i lost all my photo's and 4 years of other stuff when i had a PC incident but it should be still on the forum, search veneering and see if it comes up, the job i was doing was flat and it came out fine(was a proof of concept thingy), if you find it you will see some blue material in the bag and some white tubing, the blue stuff is a plastic mesh and the white is spiral cut tube (stuff for tidying wires), think maplin was cheaper than the composite site. this just ensures the vacuum reaches all parts of the surface as i was concerned that the bag would just suck down locally @ the vacuum inlet.
Hope that helps
regards
Mike

[Tenson]

I have a vacuum storage bag the sort used for putting clothes in storage. It is way too delicate and gets leaks after just 2-3 uses.

I want to know where to buy suitable vinyl sheet and the cement. JoeWoodworker sells 30gauge vinyl (is that about 700 micron?) but he is in the US so shipping makes it silly to buy there. FabricUK sell clear PVC sheet but do not mention the thickness. Do I need a specific type of PVC sheet?

[mekanik]

Just had a quick surf, what you are after is silicone sheet, just type vacuum veneering silicone sheet. that should give you plenty of options.

[Tenson]

I don't think that is what I want it is super expensive and I'm not sure I can glue silicone together easily at the edges. I need vinyl sheet.

[mekanik]

That's why i went for the slip membrane(just because i had some) and it works fine with the gaffer tape to seal the edges, when you pull the vacuum the whole bag goes as tight as a drum. all i can say is it works for me. just cut the taped section off remove job and put in another one. If your doing regular production runs you might want to make a vacuum table but you will need the expensive silicone for that.

[Boyan Silyavski]

I will make my self very soon a vacuum table for sheet forming, vacuum infusion. May be you could get some idea from vacuum infusion.

So its basically a table with some vacuum seals and some switches. You could do similar and use the double seal idea to seal the bag/ there is no bag in fact/. Take a look at the video below, its for vacuum infusion, but the principle is what i like, That vacuum seals the vacuum and only a cheap sheet of plastic is needed, in your case instead of the methacrylate sheet in the video.

Its just an idea that might work better on the long run

[Tenson]

I'm going to get some of this to make a durable bag - http://www.attwoollsmanufacturing.co...ame-retardant/

This one is 0.5mm but they do a 0.7mm version too if more strength is needed.

I just need to find the best adhesive for it. I've done a bit of testing with some clear PVC strip I had and very few adhesives bond strongly. Super-blue seems to be the best. Joe Woodworker recommends something called HH66 but it is really expensive to import from the USA. I tried some PVC pipe cement but it didn't work well at all. You can get 'vinyl repair glue' for things like blow-up beds and pond liners but it comes in small tubes. Still I might give it a shot at £3 a tube. Then there is Scotch-Weld Vinyl Adhesive but I'm not sure it is suitable for this kind of sheet rather than solid PVC.