Very cheap vacuum pump for vacuum bagging

I found out that you don’t need a professional vacuum machine to vacuum bagging. I was able to laminate a board and a hydrofoil wing using a diaphragm vacuum pump that cost about $10.


To use such a pump, the most important thing is to have a whole vacuum bag, without holes.
I assembled a vacuum unit on this pump. It includes the pump itself, a power adapter, a electronic pressure gauge, which I assembled from a vacuum membrane from a car and a strain gauge, a controller, a vacuum pressure gauge, and hoses and plumbing fittings. I assembled the controller based on an Atmega microcontroller, a digital LED indicator, and an encoder. A MOSFET is used to turn on the pump. I printed the controller case on a 3D printer. The entire setup is assembled on a piece of plywood. As a reservoir, I used several pieces of polypropylene pipes soldered together. This receiver was quite enough for me. As vacuum bags, I used clothes bags to vacuum the wings, and a mattress bag to laminate the board.



The photo shows me gluing the carpet to the deck using a vacuum. Previously, using the same setup and bag, I covered both sides of the board with fiberglass.
I do not recommend assembling a pressure gauge like mine. I just couldn’t find a pressure sensor at a reasonable price at first. Then I found suitable vacuum sensors on Aliexpress, but the setup was already assembled, so I left it like that. It works fine for me anyway.

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Supplement. The pump has a low capacity, about 6 l/min. Therefore, it takes several minutes to remove air from a large bag. But then, when the pump has removed all the air and if there are no punctures in the bag and all the connections are tight enough, the pump turns on for a couple of seconds at intervals of 10 - 20 minutes.
To speed up the removal of the main volume of air from the bag, you can use a vacuum cleaner or a household vacuum pump for clothes.
The maximum vacuum that this pump provides is about -70 kPa (-0.7 bar). This is enough for most fiberglass lamination and molding tasks.