Are specialized vacuum pumps really necessary?

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#1

Hey guys,

I see industrial vacuum pumps that cost $1300 and more consumer oriented pumps for $200 and the only major difference is that the $1300 one doesn’t discharge any oil - it’s a dry pump. But is that really necessary for vacuum infusion because doesn’t the oil just get sucked out of the resin and into the atmosphere? How does the oil get into the laminate? Does it just evaporate from the pump and get deposited onto the carbon fibers? Then cause delamination failure?

Btw, for vacuum bagging, even if significant amounts of oil are put out, wouldn’t the oil just get blocked by the epoxy and never even touch the carbon fibers?

-Gene

#2

The oil typically doesn’t get into the fibers duing infusion of vacuum bagging. It gets pumped into the atmosphere of your shop.

#3

So does that mean using the cheap $200 pumps is fine for infusion?

#4

What pump are you looking at?

#5

http://www.amazon.com/Robinair-15310-VacuMaster-Single-Stage/dp/B005CO9GX6/ref=sr_1_1?ie=UTF8&qid=1365364815&sr=8-1&keywords=vacuum+pump#productDetails

#6

There are other differences as well. The industrial stuff, given the price tag of 1300 dollar, as you state, has a much higher evacuation rate, has cast iron vanes, which basicly last forever, probably an oil cooler, etc.

But for hobby work a Robinair can be OK, if you know what you are doing.

#7

I thought another problem with cheap pumps was that when you turn it off the bag/job is still holding vacuum and it can actually suck oil out of the pump that way and contaminate the job? Or is that the “if you know what you’re doing” part - knowing to disconnect the line if the pump is off?

#8

There should be a one way check valve between the pump system and the bag.

#9

Usually there are one way valves, although the really cheap ones even lack these.

On airco evac pump these usually can be identified by a square block with electric wire on the inlet.

#10

I wouldn’t worry about the oil but don’t forget the cost of the materials being used during the infusion, depending on the size of the part you could easily have hundreds or thousands of dollars worth of materials that could be ruined if your $200 pump stops working.

#11

Probably a good idea to pipe your exhaust outdoors if possible. Oil vapor probably not a good thing to settle on some surfaces like fabrics and surfaces to be painted.

#12

Robinair 15600’s work great if your in this for a hobby. If your trying to make a business out of this get a professional vacuum system.

#13

Can you recommend me some good professional systems for around $1000? Thanks.

#14

I’m interested in this as well.