Cheap shortcuts to trying vacuum bagging

General Composites Discussions Composites Talk
#1

I will probably catch some flack from some of you pros, but I’m going to ask this anyway ---- because I’m going to vacuum bag a part with stuff I have around the house – just to see how this stuff works :wink:

Get your “flack” ready. :smiley:

I got some plastic hallway runner because it has small grooves underneath. I’m thinking this will help the air move through my mould. I also got some 3mil sheeting for the bagging material. I got some 1" ID clear milk hose to for the vacuum tube and a ball-valve to shut off the flow once the air is sucked out. I have modified a flange to attach to the hose and go in the mould - it is a cover to protect bicycle wheels during shipping. I plan on using duct tape to seal the edges and am going to use my ShopVac to suck.

If this comes close to working, I might make a venture (s/p) valve for my air compressor. We used to use these to suck external F-16 fuel tanks together in the Air Force. I also have a compressor off an old refridgerator that might work also.

I know you’re supposed to have a pressure guage and use certain pressures, but I just want to experiment before I spend too much.

So please tell me if you think any of this will work at all. Please be nice and be constructive. :wink: I totally understand if you laugh and call me names, but please don’t type it :wink:

#2

I don’t think the plastic hallway runner stuff will work well if it’s what i have in mind. And the shop vac can’t pull enough vacuum. Just enough to press the plastic onto the layup, but it won’t apply much consolidating pressure. The 3mil stuff will be ok, and the duct tape should seal decently.

#3

So the plastic runner would be to stiff? Do you have any other suggestions on something to let the air pass? I can’t just use the 3mil sheeting by itself, right? I need some sort of corrugation, right?

Maybe I’ll see if I can get that fridge compressor to work, since the shopvac won’t do much.

Thanks for the tips. As soon as it warms up, I’m heading to the garage to try it. :smiley: It’s freaken 40 degrees in the middle of May. :mad:

#4

the shop vac does work i produced parts with one for several years it would pull about 7in vacume parts were resin rich but imposiable to hand lay

#5

Also, check out wood working suppliers like Rocklers as they bend wood with a vacuum bagging type system.

You might even get lucky with those vacuum clothes storage bags too. What you want are PE bags as PER does not stick to PE (Polyethyene) plastic sheeting.

For the breather, maybe some thick old plaid shirts (where’s Al from Tool time when you need him…) or cordoroys pants?:eek: But it has to on top of the peel ply or PE film and if it leaks over…it all locks together as one!

#6

You can make your own “peel ply” by poking a bunch of holes in the 3mil plastic. Use a spiked roller or a hole saw and run it across the plastic. Use fluffy paper towels for “breather.”
Then bag it normally.