Vacuum pump

I vacuum bagged two bulkhead panels last night using a robinair 6 CFM pump. About an hour after turning the pump on, it overheated and shut off.

My bag had a very small leak in it that I couldn't find but I've decided to get a continuous duty pump. I'm looking at the gast pumps and welch pumps and the variety of pumps available is staggering. Ultimately, I will be bagging a 17-ft hull so I need a pump that can handle a bag setup of this size.

This one will develop around 27.6 in. of Hg and and will move 7 cfm:
WELCH-THOMAS 2585B-50 DRY VACUUM PUMP

The welch duo seal pumps look good too, although it doesn't look like they move as many cfm.

Then there's the gast pumps. There's so many gast models I'm not sure where to start. The gast 6hCA looks more than capable but it's a piston pump and it looks like rotary vane pumps are more popular for whatever reason.

Any guidance would be greatly appreciated. My budget is $800.

 

I think your Robinair will do the job. Two issues, heat and continuous service. If you can resolve either you won't need a new pump. Heat: Get rid of it, setup a small fan to blow on the cooling fins of the pump. Running Continuously: Stop that. Find the leaks and seal them.

I found a way to cycle my Robinair automatically at joewoodworker.com

We've discussed this before.

http://www.boatdesign.net/forums/fiberglass-composite-boat-building/infusion-pump-33015.html

http://www.boatdesign.net/forums/fiberglass-composite-boat-building/vacuum-pump-size-20419-2.html

If you're moving your project into a full blown production environment the investment in better pumps is essential. If this is a one-off project I'd save my $800 for fitting out the boat.

As much as I'd love to have a gizmo like the Accutrak VPE 1000 I've had pretty good success with my $3 Spy Ear finding leaks.

http://cgi.ebay.com/SPY-EAR-VOICE-A...739?pt=LH_DefaultDomain_0&hash=item4aa97187cb

Good luck with your project.

 

Knotty:
Thanks very much. I had read the threads you referenced but when I started looking at pumps I still had a lot of questions. I spent some time reading yesterday and finally ended up ordering a Gast rotary vane 3/4 HP pump. I hope it will fit the bill.

I understand that any pump is working harder if it has to run continuously and as such, I need to make sure I'm getting a good bag setup. However, I want the pump to be able to handle the load if I can't find/stop all of the leaks. Hopefully the Gast I ordered will have no problem fitting this bill.

I appreciate the response very much.