Repro rubber

[Rob 201]

re: vacuum pump, Fantastic Don, I have two ideas how to use it: one is to degas the pre-polymer so I can reduce the amount of bubbles in the mix, the other is to use it to draw polymer into molds (like reverse injection).

For degassing I started with a thick wall steel pipe and welded a base to form a steel "bucket". I have welded and machined a ring/lip on to top of to hold a bit of inch thick perspex. It has an o-ring seal. And it has a 1/2 inch outlet near the base. It's volume is about 7 litres (about 1 1/2 gallons I suppose). I need a pump that can give me a reasonable vacuum in that for about 20-30 seconds - so not huge. For reverse-injection I will just t-piece of the suction line from the "bucket" to a hose/tap/nozzle so I can use the same pump for mold filling.

I have thought about using the smog control vacuum pump of say a mazda car, but have been told it won't generate enough vacuum. My  urethane supplier mate says buy a proper one. And that is as far as I have got. So Don, I really have no idea about vacuum pumps. Type and size is a mystery to me. If you could ask your co-workers what pump they reckon would do the volume and time I need I would appreciate it. Um, there might be a problem with the electric motor voltage. I'm not even sure if the pumps are stand alone or if they have seperate motors (that I could switch?). Either way think I have a transformer that could drop the voltage to US specs.

And of-course I will pay the freight. Please let me know how you get on. Thank you again and again



Rob Wager
(ozktm parts guy)

[peter kane]

Hey Rob,

I'll have access to a digital camera over the weekend and will email you as soon as I've downloaded the pix.

Thank you so much for doing this!





Peter Kane
V3442
Plainville, Massachusetts
[email protected]

[Chakka]

Tommy, Speed and Sport has the fork whiper with brake cable guide in stock. Kurt tipped me off to them and its now installed on my bike, fast service, I recommend those guys.

Rob, I will email you later with pictures of what I am sending. If you could repro those Magura parts Id be a happy man.

Chris