A Little Of Topic!

[mr3000]

Hi, I'm new to the forum, I'm not into boat making but I figured ya'll could help with my topic. I'm wanting to start fabricating custom composite parts for cars, my questions has to do with vacumm bagging, could I use a 6hp shop vac that moves 245cfm instead of the 1/2hp 6cfm vacuum pumps that are expensive?? any feedback would be great!

[the1much]

i do mostly just hand lay up, but from alot of mishaps with things kinda like that i think if ya ask the pro's they say that the vac only "moves" that much in a even air pressure,, turn on ya vacume ,listen to it, now stick a garbage bag on the end of the vac turn it on, now listen to it,,keep it on there for a few minutes,, but keep close eye on the temp of ya vac motor. i think once it gets to a certain pressure it wont pull much, and vacume bagging the pressure is what draws the resin through and everywhere

[SamSam]

Vacuum bagging doesn't rely on quantity but quality. How many inches of vacuum you can pull is what matters. Once you have pulled the air out, there is no more, so volume doesn't matter. A shop vac won't pull a whole lot and the motor tends to burn out pretty quick. Very noisy, too. Junked refrigerator compressors work good and are usually free. Two tubes come out, one's pressure and the other is vacuum. You need to put a vacuum gauge in the line and a valve also. The valve can be cracked opened to regulate the amount of vacuum, closed gives the most. Basically the layout is 1. vacuum pump 2. valve 3. gauge 4. catch pot 5. part to be bagged. The catch pot catches any excess resin so it doesn't get sucked into the gauge, valve and pump and ruin them.

[KnottyBuoyz]

Hey Mr3000

You might want to check out www.compositeforum.werksberg.com

This site is setup specifically for composite enthusiasts who produce all sorts of parts for cars and bikes. You'll find plenty of good info there and a few knowledgeable participants.

Sorry don't mean to take you away from boatdesign.net but you might find more/innovative answers to your questions there.

I've set myself up to do some carbon fiber and fiberglass composite construciton and have infused a few parts. If you drift around here you'll find the posts of my tests. I can attest to the fact that your shop vac will not pull enough vacuum to infuse a part. Vacuum bag it maybe yes. I picked up my Robinair 15500 vac pump off of e-bay brand new for just a tad over $200 and added all the bits and pieces to make it work another $300. Not exactly cheap for a hobbyiest but if you're going to be producing parts for sale then you'll need good equipment.

There are some good video clips on youtube.com of a few guys on the werksberg forum doing infusions of car parts, hoods, hatches, panels etc.
Just do a search on youtube for "resin infusion" "infusion" "epoxy" and you'll find plenty of good clips. Try this one for a start.

http://www.youtube.com/watch?v=iylkt9aDB6Y

Any other questions don't hesitate to ask.