Does any one know where we can get 12 activated double action solenoids? Where is a good place to get them?
Try Coast Pneumatics. Just type the item number from the SMC solenoid into the part search page. Last time I checked (about a month ago), they had a bunch of the solenoids identical to the SMC ones from the Kit of Parts of seasons past, just not necessarily in stock.
Single Acting: VQZ2121-6LO-N7T
Double Acting: VQZ2221-6LO-N7T
When you order SMC solenoids, just be sure you are also getting the base (or manifold) and the cable that plugs into them if you order that style. These things come in a million different variations.
a simpler type to use might be a 4 way Mac valves
http://www.macvalves.com/distributors/usa.htm
make sure that you do not exceed the Cv rating of 0.32
the 46 series is looking pretty good.
Do you have a local Fastenal store? If so try part numbers:
0422823 SY3140-6LZ 12VDC Single Base Mount Solenoid - List $60.75
0422824 SY3240-6LZ 12VDC Double Base Mount Solenoid - List $90.17
0422828 SY3000-27-1T 1/8" NPT Base Mount Valve Subplate - List $11.80