Turning Archive 2005

Subject:
Re: Vacuum and the Nova 3000
Response To:
Vacuum and the Nova 3000 ()

Barry Irby
>Jorge,
I too built one and I have the "flat" chuck and the drum of cannister. The flat chuck is just a piece of MDF on a faceplate and I used black Neoprene foam glued to it. I rounded the outer edge and rolled the neoprene over so a large bowl or plater could seal on the edge. For the drum i used a piece of plywood scrap and a piece of PVC pipe that I happened to have about four inches long and put a ring or donut of plywood on the outbound end and cover that with the neoprene. Both work well.

I have the Nova 3000 and used a 42 MM double sealed bearing in the bearing race. I assembled a little contraption of pipe fittings that includes a vacuum gage and a valve that lets air in to control or break the vacuum. The bearing just slips in and out and that how I install and remove the vacuum.

Give some thought to all the air leaks. The hand wheel leaks where it screws onto the the shaft. I solved that with a small O ring. The fitting I bought to fit into the bear leaked. I solved that by chucking it and filing it to fit the bearing and then filing in two groves for O rings and then pressing them into the bearing. The chuck or face plate leaks where it screws onto the shaft. I solved that by cutting a rubber gasket and gluing it onto the face of the nut where it pulls up against the shoulder on the shaft. That worked well except that the action of putting on and off pealed the gasket off the nut. Now I just use a larger O ring.

I have a relatively small vacuum pump and found it necessary to be very attentive to sealing up all the leaks. I put a bead of silicon rubber caulk between the faceplate and the MDF or plywood. I put silicon in all the screw holes for the bolts. I put silicone in the groove the PVC pipe is seated in. Just coat the whole thing in silicon.

I used Spray on "craft" cement similar to contact adhesive to glue on the neoprene. I wish I had used something stronger or more aggressive. It was really designed to be pealed off later and that is not what you want.

If you use plywood as I did you will have to seal the end grain as well. Mine was made out of some coarse wood and the pump would sucked air right through the wood in the plys.

Someone put me onto a great article about this. if you want I will try to find it and forward it on.

Incidentally, I have never had the black neoprene leave a black mark on anything. I bought 1/8" think stuff at an industrial gasket supply place. I also hear that Walmart has "foamies" that are some suitable foam with sticky on one side.

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