This vacuum pump I have built for vacuum bagging of composites. I have used the idea HERE, but used another, more robust, air compressor.
If you want to buy a pump, the best value for money is the ECVP425:
2. The used 12V air compressor
The 12V air compressor is sold under several names from €30:
- Ningbo Lingsheng Electric Appliance LS4028
- Mannesmann 12V compressor
- Air compressor CTO28395
- RING AUTOMOTIVE 12V Heavy Duty Air Compressor Kit
3. DIY vacuum pump facts
- Vacuum: 0.1bar
- Current consumption: 5A
The achieved vacuum is around 0.9 bar, professional vacuum pumps realize 0.9 to 0.999 bar (gauge pressure, 1 bar means absolute vacuum).
Here are the pictures of the vacuum pump. The heat sink provides extra cooling when the pump is wrapped in a duvet for noise reduction. This will prevent neighbors quarrel. To avoid loss of vacuum caused by small leaks, the pump can operate intermittent, with an optional timer.
4. Required parts
- Extension nipple from Sclaverand to Dunlop valve:
- Flange screw M3 and M3 nut.
- Reinforced PVC hose, 6 mm inner diameter. Special vacuum hose are too stiff, which can harm the extension nipple.
- The vacuum pump timer is optional.
- Remove the valve plate and cylinder head.
- Remove the valve of the cylinder; this will be the exhaust valve.
- Seal the two holes of the cylinder with epoxy.
- Remove the valve of the valve plate; this will be the intake valve.
- Drill a 6mm hole in the valve plate for the exhaust valve. Drill a 2mm shallow hole for the valve lip:
- Flatten the valve plate with sandpaper (on the other side of the rubber ring).
- Glue the extension nipple with epoxy into the intake valve hole (on the other side of the rubber ring).
- File the M3 screw head down to 0.5mm thickness, see the image.
- Mount both valves with the M3 screw. The intake valve comes at the original place again. The exhaust valve comes on the other side.
- The screw head must sometimes be bent, to let fit the intake valve precisely to the rubber ring. The rubber ring may not leak and must keep the vacuum constant.
- Put the valve plate and cylinder head back. Note: The valve plate is now reversed.
- Mount a heat sink and use thermal grease.
6. Avoid vibration during resin degasification
At resin degasification, the work table can vibrate due to the vacuum pump. This causes the resin splashes around in the vacuum chamber. A vibrating vacuum pump should be kept away from the work table.
7. DIY vacuum desoldering station
With the vacuum pump, a simple and cheap rubber ball desoldering iron can be changed into a great vacuum desoldering station:
Use a footswitch to switch on the vacuum pump.
8. Vacuum and the human being
- A human being may survive a period of more than 1 minute in high vacuum, and will not explode!
- The maximum vacuum that can be sucked by mouth is about 0.3bar.