sealing a large vacuum bag?

[Mr DIY]

Hi all.

Did a quick search and did not find anything, so apologize if this question comes up again.

I wish to seal a rather largish vacuum bag. For my smaller bags, I have a plastic rod the fits into a plastic strip resulting in a pinched bag and thereby creating a good seal. For my larger bad, I have a problem in that the existing tools I have are two short.

Has anybody made up some form of sealing system for larger bags? I am needing a good seal with almost no leaking. The use of one-time sealing materials is not an answer for me.

Anybody with some good ideas?

[Ollie]

Get a longer rod. The cheap fiberglass rods used as bicycle flag assessories come to mind. Or you could also use a length of brass or aluminum tubing. Wrap the open end of the bag around the tubing and apply a strip of wood to each side of the doubled bag as close as possible to the rod or tubing. Apply several spring clamps to the pair of wood slats to squeeze the doubled bag between them.

[Mr DIY]

Hmm .. sounds like a good idea. Must give it a try Thanx Ollie.

I am using a fridge compressor as a vacuum pump and trying to get a good vacuum in order to prevent pump running all the time. I use a gas bottle and and a pressure sensor to regulate pressure. I Need the best seal I can get.

[Ollie]

A little petrolium jelly smeared around the inside of the tube opening for an inch or two might help to perfect the seal. Be sure to use plenty of clamping pressure at the edges of the bag where it folds sharply over itself.

[RSCherry]

I use clear packing tape. Works fine as long as you are careful about smoothing out any wrinkles in the bag. I have successfully made 60" x 120" vacuum bags out of 2 60" x 120" sheets of PE with tape joints all around using this method. they are not air tight, but they work well enough.

[Mr DIY]

they are not air tight, but they work well enough.

Hmm ... not good enough. It is OK for a small bag, but I have found that no matter how careful I am, they leak too much. They may even start out OK, but can leak after a while. If you have a vacuum pump that runs continuously, then not really a problem.

Mind you, it also depends on vacuum you trying to pull. For me though, tape is not an answer. Thanx anyway.

Ollie .. the idea with the jelly sounds really interesting. Must give it a try. Thanx.

[Bigfootbis]

Try using a device made for sealing vacuum bags for freezers. This is a hot-wire device and the seal is permanent. I have bags done this way which are well over 10 years old.

[Ragged]

Butyl tape is the best. The stuff I have works great to seal the bags we sell in our kits. You can open the bag and close them more than once without a single leak. We have 50 foot rolls that come with our Etap kits.


Ted
www.roarockit.com look in the RC area.

[steve lewin]

If you're going to resurrect these old threads I guess they should now be in the Composites forum.

Steve

[Mr DIY]

Steve .. how do we get this thread into the composite forum? Are you saying we should start a new one or something. Dont quite follow. :)

[Schwemmer]

I have seen people use caulking (for windows). It comes in a tube. You squeeze it out then attach both sides of the bag, then clamp it shut. It does not leak even overnight.

Rick

[Mighty Mik]

I just bought a 12" 'impulse sealer' from eBay... it will give me 12" x 2mm wide
seals. I've also seen that hand held gizmo for resealing chip bags and such...havn't bought one of those yet.


Try using a device made for sealing vacuum bags for freezers. This is a hot-wire device and the seal is permanent. I have bags done this way which are well over 10 years old.

[Juko]

Yeah some cheap caulking works great for making a seal.