The impact of tubing sizes

[C'DaleRider]

The choice of wall thickness has to do mainly with turning radius. The larger the wall thickness the less problems with making sharp bends and having the tube collapse. I think someone else also mentioned less problems with transfer of coolant through the tubing wall. I believe that was what Cathar was discussing when he wanted a 8mm ID with a 12.x OD.

Interesting you mentioned the fluid transfer through the tubing wall. It's not something I've seen a lot of mentioned here, but I'd think it'd be a problem and concern for long-term setups.

I was doing a bit of reading on Saint-Gobain's website (mfgr. of Tygon), which is tygon.com or labpure.com, and the water absorption rates for various formulations of their tubing is listed.....but you have to dig for it.

For instance, Tygon 3603, a very popular tubing here, has an absorption rate of water of 0.24% (figure represents percentage of water absorbed in 24 hours at 23C.)

Tygon F-4040-A, a fuel line formulation, has a permeation rate of 0.49%.

Tygon B-44-3, beverage tubing, has a rate of 0.13%.

Tygon B-44-4X, a food, milk, dairy tube, has a rate of 0.15%.

Tygon LFL, long flex life tubing, has a rate of 0.18%.

Tygon Silver antimicrobial, the best at rejecting water absorption amongst Tygon tubing that has a working psi range of at least 20psi (I rejected any tubing rated for less than a 20psi working pressure), has an absorption rate of <0.01%.


The water absorption rates were not dependent on tubing thickness but were only a property of the tubing compounding, obviously. So naturally, the thicker the walls of the tubing, the slower the effects of water absorption would be to show. But it seems to me, given everything else being fairly equal, that the lowest absorbing tubing should be in consideration as tubing to be used.

Granted, Tygon Silver isn't equal with other formulations of Tygon or other tubing....its bend radius isn't the best @ 1 1/2" for the 3/8"ID-1/2"OD tubing, but it has other properties going for it. One, obviously, is the antimicrobial property. Another is its higher resistance to alcohols than other Tygon PVC-based tubing.

It is, unfortunately, a little stiffer with a Durometer rating of 72 vs. the 55 of the 3603, but I don't know if that is significant enough to be that much of a difference.


I also wonder if the use or exclusion of plasticizers on the inner wall of the various tubing choices available to us has any effect on its durability, longevity, and any other effects plasticizers may play in a cooling loop. Or does it make any difference at all? Can plasticizers leech out of the tubing and eventually coat the working parts of, say, a cpu or gpu block? Or is this not a real concern at all?

Thanks for the info!!!


J.M., RN, BSN, CCRN, CEN, CFRN, TNS