Building your own Vacuum pump
Introduction
What the hell a step-by-step instruction to build a vacuum pump is doing on a site dedicated to the electric helicopter?...
I must admit that it may sound strange but I will list you some application that may bother the heli pilot you are. For example, you may use it when building your own self-made canopy, a new composite undercarriage (ask Bert) or a set of custom blade. In fact everytime you will need to press something for quite a long time.
This is often the case when you work on something using composite (such as carbon fiber, glass fiber tissue, Kevlar,...), you always need to press the different layer on a shape and keep them in place in order to let the epoxy polymerise.
People often use heavy loads, sand bags, their collections of magazines or anything in the neighboourhood looking heavy but they never obtain a regular and optimal pressure on all parts of the work. By using vacuum, you can apply the same high pressure on all parts. How can this be achieved?... Answer: by using athmospheric pressure! All you need to do is put your items inside a polyethylene plastic bag and use a vacuum pump to lower the pression inside the bag.
A depressure of -100 mbar gives a load of 100 kg per square meter, if you apply -500 mbar, you will end up pressing 1/2 ton per square meter. Our problem now is to get a rotary vacuum pumps and a regulation to do it. You can find some on the market but at a retail price that will make you think twice before buying it. Other solution is to build your own. The solution I will describe here has been validated and I will explain you how to build it for almost nothing.
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