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Unread 03-10-2004, 01:58 AM   #7
Cathar's Avatar
Join Date: Sep 2002
Location: Melbourne, Australia
Posts: 2,538

Originally Posted by UberBlue
Have you considered hypodermic needle tubing? It's relatively cheap, stainless steel, and available in every size down to gnats ass.

The hypodermic needle's 304/316 Stainless Steel (as with all stainless steels) will rust if left sitting with still water in contact with it. What this means is that once the block is installed, you basically cannot then take it out and leave it sitting about unless taking a good deal of care to dry it totally.

One of the materials we're looking at making the middle plate out of is 420 Stainless Steel (commonly used for cutlery), but again has the same issues with rust if left damp. The plate would be machined, drilled, and EDM'ed into a single solid piece.

The corrosion process is also accelerated if the steels are left sitting in damp contact with copper or silver, possibly leading to blocked tubes. As long as the water is flowing, it's all good.

I'd like the blocks to be fairly maintenance free in terms of corrosion, without the need to pull them apart and dry them out every time the block is removed from the system.

We're still trying to see if we can conventionally machine the middle plate. The first material we tried was too brittle.
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