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Ball joint - Heated lid for OpenPCR
Asked by Tito Jankowski
Posted Sep 07 2010 06:12 AM
We are working to design our heated lid so that it can adjust to small differences in the size or height of tubes. In PCR, we're cycling the temperature of a small aluminum block between 50C and 100C. We place a plastic tube in each well of the aluminum block, which contains a liquid DNA sample. Now, if we simply have this setup, we will heat our samples to 100C and they will evaporate and condense in the lid of the tube. This is a problem, which is commonly solved by something called a "heated lid". The 100 C lid needs to make contact with the caps of the PCR tubes, to prevent condensation of the sample. At this point, we have a flat aluminum plate with a heater mounted to it, and are able to reach 100 C. The issue is having the plate make flat contact with all 16 (4 x 4) tubes in the OpenPCR. I'm looking for some sort of a ball joint that we can mount the plate to so that it will rotate every so slightly (10 degrees would be enough).
Now, I know I've seen a part like this in existence, but we have little idea where to find it or what is it called?
I would describe it simple as 2 flat plates with a ball joint in between. The size of the plates should be smaller than 1.5" square, with a few holes in each plate for mounting. I've drawn up a crude illustration to attempt at describing this, and have searched mcmastercarr ("ball socket") got me the closest, but no cigar.
Here's some "similar" products to what I have in mind...but looking in the <$10 price range and much smaller:
(car gps mount) http://www.cabelas.c...44012724a.shtml
Hope you have ideas in mind!
Answered by idfarmer
Posted Sep 08 2010 01:20 PM
Is there a reason you're specifically looking for a ball joint? I know you guys are trying to source as many parts as possible, but a floating hinge (like a panini press) should work really well, and isn't nearly as complicated to fabricate in house or through ponoko. It has 4 relatively simple points of rotation, and you wouldn't have to worry (too much) about it tipping if you only had a few tubes in your block.