I'm working up a demo model of a special purpose pump (sorry I can't be specific about its' function). and need to find some appx 3 inch dia X 1/4W acryllic tube. The ID needs to be round and smooth enough for a sliding O-ring seal,similar to a hydraulic cyl. Pressure will be low, about 20 psi. Does anyone know of any suppliers for a tube that fit the need?
Thanks
Someone may prove me wrong here, but I can't see extruded acrylic tube being round enough for a good seal. Even small-diameter glass syringe tube is only round enough for an approximate seal, although it works well when the elastomeric seal is relatively thick -- as it is in a syringe.
If you can use a thick seal, it's probably no big deal. The tradeoff there is getting a seal that's soft enough to fill the gap but which will hold 20 psi (probably not difficult, either). But if it has to be an ordinary O-ring, and if you need consistent resistance from one unit to the next, I'll bet that you'll have to hone the bore to get that close.
But maybe someone knows of a source of such tubing with precise bore roundness.
-- Ed Huntress
Have you tried McMaster-Carr?
Yes, I'd avoid extruded tube. McMaster carries cast acrylic tube which should be good enough, depending on the the compliance of the seal. Easiest way to find out is to buy a piece.
8486K557 (Same as 8486K555) Clear Cast Acrylic Tube 3" OD X 2-1/2" ID, 1' Length In stock at $23.88 Each.
have you tried tap plastics?
Try Modern Plastics. My local branch in Warwick RI and they are pretty good about helping me out when I am befuddled.
Errol Groff
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