How long can i run the vac pump ? do i just ensue that i have a good seal and as soon as the max vacuum is created stop the pump ? My pump is the standard EC unit.

Chris A

wwwbartonphoenix.moonfruit.com

You can leave your pump running as long as you think is needed, check now and then if the pump is not getting to hot and check oil level...

Hi

Many thanks for the reply, is it worth placing a T piece in the vac side and fitting a gauge to monitor the vacuum ?

Chris Alty

http://www.bartonphoenix.moonfruit.com

Hi Chris
It is my understanding that a oil bath vacuum pump must not be left on for long periods of time because they get way to hot. What those that want a pump to run 24 7 get, is a air vane pump. These air vane pumps only get to about 24 HG of vacuum where as the oil bath vane pump like yours will go to full 29.9 Hg vacuum. I hardly ever use my air vane pump anymore now that I get fully sealed bags every time now. I do the half hr drop test, infuse , seal off the lines, shut off the pump, and then cut the tubes off. I then go on to the next part and do the same. Some times I do 5 parts and put them in my oven. I have to admit it was scarey to shut the pump off and cut the lines at first, but now its routine.
Hope this helps.
Fred 

Our Composites Vacuum Pump can be left running for long periods and certainly for long enough to complete the cure of an infusion process or vacuum bagging process as room temperature. 

You must ensure the pump does not run out of oil, and you also must ensure the pump is pulling against a sealed bag.  Running the pump for prolonged periods against a poorly sealed bag or against virtually no vacuum, will eventually damage the pump.

Many people still leave the pump on throughout the infusion cure and our pump is perfectly capable of doing this subject to oil and a good seal.  We regularly leave the pumps in our workshop running for 24 hours plus when we are doing pre-preg and leaving it to cure in our ovens overnight.

You will find that with a good bag seal, the pump will also use very little oil as it is under little load.

However, generally with resin infusion, we recommend aiming for a perfectly sealed bag so you can shut off the pump on completion of the infusion.  Even with a physical barrier to stop the resin reaching the vacuum port, it only takes a small amount to find a path to the vacuum line and then you will loose a lot of resin up the vac line into the catchpot. If this happens post infusion, then you may well dry out the part too much leaving a cosmetically flawed finish at the vacuum line end of the part where it will begin to get pinholes and, in severe cases, patches of dry fabric.

That is why we recommend getting a perfect bag everytime. With the bag sealed under vacuum and the infusion complete, the resin has no where to go and the laminate will remain stable throughout the cure and hopefully give you repeatable cosmetically perfect parts.  However, key is getting a good seal in the first place.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant