This is an easy to build vacuum chamber that is power with a garden hose. you can draw 30 cm of vacuum with your hose. simple and easy way to degas fluids like silicone for mold making without buying an expensive vacuum pump.
Step 1: Parts
you will need the following parts. many of they can be found or scrounged for free is you have the time.
1 - 6" x 24 " PVC pipe Lowe's $16
2 - 1/4 " x 12" x 12" acrylic sheets (www.estreetplastics.com) $12
2 - 1/ 8" x 12 " x 12" neoprene sheets (www.smallparts.com) $20
1 - vacuum Aspirator (csrscience.ecrater.com) $25
1 - vacuum gauge harbor freight $13
1 - 3" x 3/8" air hose harbor freight $4
Total = $90
Step 2: The Vacuume Asparater
this little thing can draw up to and in some cases even more than 30cm of vacuum with only a garden hose. and a only $24 it beats the hell out and expensive pump. it has a ball valve to hold the vacuum when the water pressure changes so when you shut of the hose the vacuum stays.
Step 3: Top and Bottem
The top and bottom are 1/4 " acrillc .
Just trace the tube.
Find the center point, and make a circle and inch farther out.
cut along the outside line.
Step 4: Neopreen Gaskets
use the top and bottom pieces to trace around with a knife to cut out the neoprene.
find the center and then cut out the center circle by hand.
Step 5: Make the Conections
drill tow hole just a little bit smaller than the fittings (the vacuum gauge came with a bunch of extra fittings)
heat up the fitings with a soldering iroen and scre them in. when they cool down take them out and wrap with plumbers tape and reinsert them.
Step 6: Finishing the Pvc Edges
This is the tough part. if you are lucky the pipe you have will have good edges. This one did not. gab a piece of sandpaper and hold it down with the bottom plate. sand in a circular motion and keep turning the pipe so you don't over sand. Eventually you will get an edge that is good enough for the neoprene.