[beav]

I'm laying up a plenum for my engine on a mold I purchased from another builder. I had been considering buying the equipment to do vacuum bagging, but it's fairly expensive and I don't expect to do much of it. After thinking about it a bit though, I stumbled on a really cheap alternative. This is one of those Space Saver storage bags. Most of the bags they sell are too small, but they sell some larger bags labelled as hanging bags, the "suit" sized bag was perfect for the plenum and cost around $10. The material isn't stretchy, so you'll have to coerce it into corners, but there's enough slack to do this. Over the glass, I added a full layer of Dacron and a couple of layers of paper towels to absorb excess resin. I then used our vacuum cleaner to suck out all of the air. This worked surprisingly well, and the vacuum was still maintained the next morning.

 

[N395V]

An absolutely excellent idea

 

[Bob Kuykendall]

Nice!

The best I've seen from a regular vacuum cleaner is only a couple of inches of mercury, but that part looks pretty nice!

I do a handful of parts in "vacuum baggies," and one additional trick I've discovered is to tape a bunch of polyester batting over the mouth of a glass beer bottle and toss it into the baggie with the part. Then after I draw a vacuum on the baggie, I disconnect it from the pump and just cap it off. The bottle acts as a vacuum reservoir to collect the air from bag leaks and also the air that slowly percolates out of the consumables plies.

Thanks, Bob K.

 

[rocketbob]

I vacuum bag composites with an old refrigerator compressor. Works great! I do have rolls of all the real supplies but have found that 55gal trash bags save some time since three sides are already sealed, and I seal the open side with the conventional vacuum bagging gummy sealant tape.

 

[pierre smith]

Another way..

Jason, you don't have to have a bag either. Years ago, I attended a woodworking vacuum bagging veneer seminar and we used a roll of 5-8 mill vynil plastic, 4 feet wide. We made an appropriately sized bag by sealing the edges and ends with duct tape.

This way, you can have any size and shape bag you need...Highland Hardware in Atlanta holds all sorts of woodworking seminars.

Best,

 

[beav]

Pierre,

I was originally thinking that, but then you'd need the air fitting and check valve. The space saver bag has that already.

I pulled the part out of the bag this evening and the bagging definitely removed most if not all of the excess epoxy.

 

[pierre smith]

They just left the vacuum pump running 'til the glue dried...about 30 minutes.

I like your setup.

Best,

 

[hendrik]

I often use a garbage bag and an aquarium pump (modified for suction) for small parts, keeping the pump running until I take the part out of the bag. Cling foil also works (fold the edges ~3 times), but garbage bags are usually easier.

 

[Snowflake]

We used the "old refrigerator compressor" method to bag parts in university. It worked really well.

 

[Rivethead]

I've done a lot of vacuum bagging and have found that a piece of thin vinyl sheet rolled up on the edges works as well as any bag. I use window screen laid across the piece being molded as the medium to channel all the air to my piece of tubing which is connected to my pump system. Congrats on your project though it looks like it worked really well.