evil_lurker - 22-6-2007 at 01:01
Once again the UPS man crapped out a package. This time it was from U.S. Plastics and it had some heavy wall Tygon tubing inside.
http://www.usplastic.com/catalog/product.asp?catalog%5Fname=...
Stuff I got was 3/8" inch on the inside, and 7/8" on the outside... some seriously heavy walled stuff indeed.
What got me was how flexible it was... you can make a complete U bend in your hand with two fingers, and still not collapse the wall, even though its
nearly an inch thick!
I just hope its fairly solvent resistant.
not_important - 22-6-2007 at 01:51
http://www.tygon.com/Data/SiteMap/AllDocumentList.asp
3603 is listed here
http://www.omega.com/pdf/tubing/technical_section/chemical_c...
I think that it is intended for vac/air and water. The Omega charts say don't use with acetone, esters, aromatics. Even alcohols get a "moderate
effect", it could be they leach out the plasticisers.
[Edited on 22-6-2007 by not_important]
Sauron - 22-6-2007 at 03:22
So I guess that you need to cold-trap your system well, if you plan to use this for, say, the vacuum system on a rotavap when you are taking off
solvents that can affect Tygon.
The rotavvap primary condenser will catch most of the solvents, a large dry-ice/acetone Dewar condenser will snag most of the rest and a standard cold
trap ought to stop anything that gets past those.
evil_lurker - 22-6-2007 at 04:59
I got a Savant RT-100A (or somthing like that) refrigerated condensation trap, I just ain't got the actual trap for it. I snagged it off of Ebay last
year for $132 (shipping included... damn I loooove a bargain)... its old as shit, but still works pretty good, it'll get down to -35ºC no problem.
I'm working with UGT on a replacement trap, and it will probably be another week before it gets here.
I figure I'll try and use an aspirator for stripping polar solvents and the mechanical pump system for high boiling organics where I need to very
accurate vacuum for fractionating. I have a J-Kem digital vacuum regulator (which needs to be recalibrated since its off by about 10 torr... I should
be able to compensate for by distilling some water at known temperature/pressure points and get accurate temps)
I'd love to have a rotovap but that will be sometime in the future.
bio2 - 22-6-2007 at 08:47
This type of Tygon vacuum tubing will slowly harden as the plasticizers eventually get washed out when exposed to solvents.
A better choice for solvent resistant vacuum tubing is the
black neoprene type fuel line as used in automotive applications.
It may outgas somewhat more than the thicker vacuum tubing
and is not quite as flexible but is for most intents and purposes
adequate for the job we would use it for in vacuum applications.
This fuel line is pressure rated with an internal reinforcing
braid and will not collapse under full vacuum. Also it is
available at any automotive store. Just ask for the thick
wall version of black "rubber" fuel line.