This is Warren's specialty. No one does vacuum bagging better... Warren?

I've seen and played with a venturi vacuum generator, but didn't think it could pull as much vacuum as I wanted. I ended up buying a surplus vacuum pump from Aircraft Composites I think it was. Cost $130 or so and probably had to put another $40 in fittings and a pressure gauge into it. This pump is great. I can reliably pull 25"-26" of vacuum at 7000'.

I should say that many people get good results with venturi vacuum units, I just believe in overkill - I don't want to buy a tool and then find out afterwards that it won't do the job. I bought a tool that I knew would do the job and figured if I didn't use it again, I could always sell it.

There are a lot of tricks I've learned along the way - the most important is having EVERYTHING cut perfectly and ready to go before you start. Once you mix epoxy, you better have everything ready and right there at hand. The biggest issue is generally building the vacuum bag around what you're doing and getting a good seal all around before the epoxy gels on you.

Some things are easy - plate stock being trivial.

Tubing is an art all of its own and depends massively on your mandrel. Paper or phenolic mandrels need special consideration on how the v-bag is built to ensure that you don't crush the mandrel. Metal mandrels are fairly trivial.

Unitary fin cans are my specialty and for that sort of project you really need extra hands. For instance the UprOar Project, JW's Casey Mae, my L3 and a couple others have absolutely depended on having one or two other people who can help with handing you things, holding things in place while the bag is constructed, mixing epoxy, etc. etc. I have to say Joe Hinton and John Wilke have been indispensable in making those projects a success.

One final thing, there are some serious issues around designing your bag, what bagging materials you use and how you lay up the release and breather material - all very specific to your design.

Feel free to contact me and I'll be glad to help.

W