: Roy,

: Its a Dayton Speedair model 4Z335. The Flow rate isn't marked on the pump,
: but I believe its around 2 to 3 cfm open flow (similar to Gast rotary vane
: model 0325). I just tried to find the specs online and there is an
: identical pump on E-bay (which is where I bought mine) right now for $55.

: Resin infusion typically uses "full" vacuum (25 - 28 in-hg) for the
: pump down cycle. The vacuum switch I have is a bit temperamental, and it
: works best between 20 and 25 in-hg. I also used "full" vacuum
: for the infusion and through to gel, but some sources back off the vacuum
: after infusion. My test samples came out better with the full vacuum
: approach. Yes, the resin trap acts as the vacuum reservoir too. If the bag
: and mold seal properly, the pump is not running much. If it runs a lot,
: there is too much leakage for good infusion.

: In principle, the equipment is the same for bagging we lay-ups, although wet
: lay-ups often use less vacuum.

: Best wishes,
: Sam

Thanks Sam

I'm in the process of setting up a vacuum system and keep reading some conflicting numbers so am glad to hear what You've found to work.

some of the stuff has to do with crushing the core/mold when using foam and some of the backing off of vacuum methods seem to be counter to my thinking.

I can't really see how reducing the vacuum after the project has kicked, does any good since it's still about keeping the layers flattened and bubble free.

I still have a little time to devise my system before the weather is conducive to using ...so I'm glad you posted while I've been in the search for components.

as of now I do have a pump, but am also having dificulties finding specs since it's an older Sargent Welch pump and nothing seems to be given on line as far as specs....interesting how they can stamp a serial number and a model number, but don't seem to be able to stamp anything about capacities on the pump frame.

I'll end up just doing the testing with it to find out it's capacity and capibilities.....would be nice to have read that it would pull 29 or 30 Hg.

I like your switch system...do you know of a less picky adjustiable switch?

since I would rather go that route than the strict bleader valve method and need to buy whatever ....might as well get something that works up to 29 or 30 Hg and gives me more options for vacuum settings.

Thank You very much for the posting

Best Wishes
Roy