The impact of tubing sizes

[RickCain]

that is 6mm id / 8mm od

[elfy]

damn that's some thin tubing

[LogAn'sRun]

looks sweet, finally I see a good pic of push fits! I'd liked to get 10id if poss. . .

[pie_uk]

so bascially i can safely move to 3/8 tygon now without getting hissed and booed?

lol

[gabe]

Agreed. My personal preference is for no thinner than 3/32" walls (or 2.5mm), for just that reason. Also helps for turning radius too. I didn't state that in my OP though, but I am aware of tubing evaporation/porosity issues, and turning radius issues, for thin walled tubing.

I understand Stew. Please also appreciate that thru this conversation I am also addressing the members of this forum. People need to clearly understand how to use push-in fittings, and the way things go, my warning will be lost and push-ins will become the new thing to do, which more often than not ends up on my lap as in "why don't you make a block with built-in push-ins Gabe".. Been there, done that.. You know what I mean?

So let me be clear one more time (OK call me senile): Push-ins are not designed for low pressure environments. If you use them, be prepared to watch fluid levels often.

BTW Happy Father's Day to all the Dad's in this forum..

[RickCain]

I understand Stew. Please also appreciate that thru this conversation I am also addressing the members of this forum. People need to clearly understand how to use push-in fittings, and the way things go, my warning will be lost and push-ins will become the new thing to do, which more often than not ends up on my lap as in "why don't you make a block with built-in push-ins Gabe".. Been there, done that.. You know what I mean?

So let me be clear one more time (OK call me senile): Push-ins are not designed for low pressure environments. If you use them, be prepared to watch fluid levels often.

BTW Happy Father's Day to all the Dad's on this forum..

I agree with your concern and have tried thinner walled 8mm tubing only to find depending on where the tubing is on the roll, you could have problems (ie. the tubing doesn't stay round towards the end of a roll). It has caused a fair share of problems with leaking for me and have learned to adjust accordingly. The worst thing a user can do it to try and re-use an existing connection without trimming the tubing prior to reinserting.

I have a feeling the challenge will be finding 10mm id push to fit connectors that will work with these blocks having the inlet and outlet holes so close together.

[Cyprio]

I tried that approach and it is somewhat problematic as the screw down ring is specifically made for a specific size tube. I did get it to work, but I had to use a lathe to get the nuts ID opened up.

Hmmm... i guess that's what i need to do with my fittings to get them to close fully.

10mm OD compression fittings with 10 mm nut, using Tygon 1/4" ID, 3/8"OD:





I think Alphacool produce an 11mm nut. Maybe that will help?

[ranker]

so bascially i can safely move to 3/8 tygon now without getting hissed and booed?

lol

Nah. 3/8" isn't bad but any lower and you'll start seeing marked changes in temps. Like Cathar pointed out, the difference between 1/2" to 3/8" isn't that bad and sees 3/8" as the sweet spot.

Just choose between either 1/2", 7/16" or 3/8" to do whatever suits your needs best.

[Top Nurse]

Top Nurse, do you have pics of your rig somewhere so I could look at those fittings?

Well the [H] is down now, but here are some pics. In the first pic I have used a bulkhead connector to run tubing through the middle compartment plate. That's the one in the back. The big one in the front I cut apart and used it as a bushing to run the PSU loom through.









This was one of my early attempts. Now there are no 90's in this area at all.









Here you can see a 90 that was used to go through the middle plate and a 45 that went to the CPU.









Here's a closeup of the Cuplex XT with a pair of 45's. As Cathar pointed out a silver block is nice in keeping the biologicals down the natural way (poison them)













Here's the other side of the CPU loop.









Different types of fittings.














Here's where I had to get creative with the Koolance compression fittings because the Koolance tubing is designed to fit 9mm OD and my tubing was 8mm OD. Had a friend make me some prototype nuts.







If your interested in seeing the rest of it is on the [H]. Feeding Frenzy Interlude is almost finished. Feeding Frenzy is awaiting some new parts.

[sick_g4m3r]

^ TOPnurse, thats a ton of 90s!!

Your flow must be stand still dead.

[Grinch]

lol

[Top Nurse]

Nah. 3/8" isn't bad but any lower and you'll start seeing marked changes in temps. Like Cathar pointed out, the difference between 1/2" to 3/8" isn't that bad and sees 3/8" as the sweet spot.

Just choose between either 1/2", 7/16" or 3/8" to do whatever suits your needs best.

Perhaps you might want to re-read the first post and take a gander at the pretty pics. Actually he sees the sweet spot at 5/16" (8mm) ID because the 5/16" with a push-fit has essentially the same graph as a 3/8" with a hose barb. And in actuality the difference between the worst and the best is only a measly 1.11 C. I don't think a 1.11 C difference is going to change much in the real world.

For the various tubing/fitting sizes, the PQ curves for a full system for each tubing type looks like this:



I overlaid the curves onto the PQ graph for the Laing DDC1+

Okay, the more astute of you will point out that the block C/W is really the case-to-block C/W, and that the actual CPU-die-to-block C/W is a lot higher. Even if we triple block the C/W (which would be an absolute upper limit based upon older research), we get:

6.35mm quick fit = 50.11C
8mm barbed = 49.74C
8mm quick fit = 49.31
9.6mm barbed = 49.25C
9.6mm quick fit = 49.04C
11.1mm barbed = 49.01C
12.7mm barbed = 49.00C

I'll leave it to everyone's own personal value based judgement to determine the relative importance of the differences seen....

It's certainly not the 5C figure that people bandy about. I never expected that it ever would be myself. In my own testing with arbitrarily choking the flow-rate in a test-system, I've always been amazed at the low flow resilience of many setups. Below 2LPM is where things start getting pear shaped quickly for most systems. My recommendation is that even if you're a low-flow fanatic, always ensure that your flow-rates are above 2LPM at the very least, and preferably above 3LPM if at all possible. Still, even when given 1/4" tubing installed with quick-fits and a decent pump like a DDC2, we can see that flow-rates in excess of 4LPM aren't a problem.

[Grinch]

Perhaps you might want to re-read the first post and take a gander at the pretty pics. Actually he sees the sweet spot at 5/16" (8mm) ID because the 5/16" with a push-fit has essentially the same graph as a 3/8" with a hose barb. And in actuality the difference between the worst and the best is only a measly 1.11 C. I don't think a 1.11 C difference is going to change much in the real world.






Kaaa aaa kkkks

very true..

[ranker]

Perhaps you might want to re-read the first post and take a gander at the pretty pics. Actually he sees the sweet spot at 5/16" (8mm) ID because the 5/16" with a push-fit has essentially the same graph as a 3/8" with a hose barb. And in actuality the difference between the worst and the best is only a measly 1.11 C. I don't think a 1.11 C difference is going to change much in the real world.

Kaaa aaa kkkks

Don't try to lie about he stated:

3/8" ID | 1/2" OD into 1/2" ID push-fittings is ideal

Those are his exact words. He sees 3/8" as the sweet spot and only to use 5/16" when you must for bends.

You may not value 1C, nor performance (which is obvious from your full Aqua Computer build), but most of us over here in XS are performance oriented. Many would pay a lot more for that extra 1.11C performance benefit. There's a reason why many of us jumped from 3/8 to 1/2 a few years ago and that was due to the 1.0C gain seen at the time. So yes, 1C is a big jump, which is why most of the WC'ing enthusiasts (people here at XS) purchase thermochill, Laing, Swiftech, D-Tek, etc products.

3/8" tubing itself results in minor .01C performance loss over 1/2" tubing, hence most of us won't mind dropping in size. However, low flow system, irrespective of tubing size, will perform worse. Low flow does not perform as well as high flow. You're using his data as a rallying cry for low flow systems as seen in your other posts; trying to misinform others by applying the 3/8" inch findings towards low flow setups in general.

How about you also stop trying to apply the tubing size findings to restriction overall. Elbows add restriction which hurts performance. More restriction leads to worse temps: http://www.xtremesystems.org/forums/...1&postcount=36

(sigh)

I'll pull out ye olde racetrack analogy.

If I'm a molecule of water, circulating around a water-cooling loop, I'm just going around and around and around. It's just like being a race-car on a race-track at a fixed speed. The time I take to travel through the radiator is like the time spent travelling down the main straight of the race-track.

If the race-track is 5 miles long, of which the main-straight (radiator) is 1 mile long, in the space of 1 hour, how much time per hour do I spend on the main-straight if I'm travelling at a fixed speed of 60mph, 120mph, or 180mph?

The answer is that the speed doesn't matter of course. I spent 1/5th of my time on the main straight. 'cos the straight is 1 mile long out of 5. Even if I travel at twice the speed around the circuit, it'll take me half the time to get from the start to the end of the main straight, but because I'm going twice as fast everywhere else, I'll be on the main-straight twice as often. i.e. No matter how fast I travel, I'll be on the main-straight for 12 minutes out of every hour.

Now common physics tells us that the rate of heat-exchange is proportional to the temperature difference between an object, and something else that's cooler than the object. If I'm a molecule of water, and air is cooling me (by way of the air cooling the metal tubes inside the radiator that I'm flowing through), then the longer I spend in the radiator, the cooler I will get (that's good), BUT, the cooler and closer I get to the air-temperature, the less quickly I'll lose heat (that's bad). The two cancel each other out. So why does higher flow results in better performance?

The more quickly I rush around, the more likely I'm going to be tumbled about (think white-water rapids as opposed to a smooth slowly flowing river). This means that I'm going to get tossed against the cool metal walls of the radiator more often, rather than just cruising along down the middle of the tube, only passing heat slowly to water molecules beside me that are only a little cooler than I, because they are beside another molecule, and then beside another molecule, before we get to the cold metal wall. i.e. water sucks for transferring heat if it's not getting mixed about and thrown against the cold walls.

Hope that explains it in a "simple" manner that is intuitive, obvious, and directly counters the "slower flow is better" argument.

You want as much flow as possible to dissipate heat better within the radiator.

[sick_g4m3r]

Is it possible to get 8mm ID tubing in the US?

EDIT: nvm i like the 3/8" QF, thats the sweetest spot

[Top Nurse]

Is it possible to get 8mm ID tubing in the US?

EDIT: nvm i like the 3/8" QF, thats the sweetest spot

There are quite a few places you can get the stuff. McMaster-Carr has all kinds of metric and inch tubing available at the click of your mouse. Please keep in mind the shore hardness of the tubing so you get appropriate tubing as specified by Legris. IIRC, most of the push-fit fittings I have gotten from them are Legris brand. You can purview their requirements at www.legris.com

[LogAn'sRun]

Agreed. My personal preference is for no thinner than 3/32" walls (or 2.5mm), for just that reason. Also helps for turning radius too. I didn't state that in my OP though. . .

Not to be picky, but THAT is actually what he said later on; which wouldn't be the 3/8"ID 1/2"OD, it would be slightly larger. But this is just nit-picking right?

[Methylphenidate]

I've actually always wondered about the impact of using a 1/2" loop with a 3/8" segment leading right into the CPU block. For something like a D-tek FuZion, it seems to me that you'd get the benefit of relatively free flowing 1/2" tubing for most of your loop, but with an impingement effect directly over the die of the CPU.... Just an idle thought i had. I may actually test it at some point.

[Top Nurse]

Not to be picky, but THAT is actually what he said later on; which wouldn't be the 3/8"ID 1/2"OD, it would be slightly larger. But this is just nit-picking right?

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.

In my use of 6mm x 8mm tubing you have to be careful what kind of tubing you use as mentioned by R1ckCa1n. Actually I was the one who encouraged Sharka to get the Mazzer PUR tubing due to it's higher flexibility. The test sample that was sent worked very well with push-fits. Unfortunately the roll of production tubing shipped was wound very tight on a small roll and it malformed the tubing in such a way that negated the use of it in a push-fit environment. The stuff AC sells (have no idea what their supplier is, but suspect it is Legris) is a PUR with a limited bend radius and a shore hardness that makes it ideal for its intended application.

[Top Nurse]

^ TOPnurse, thats a ton of 90s!!

Your flow must be stand still dead.

Actually not.

I know using 90's is a no no, but perhaps this is also a size thing as well where it affects more negatively in a higher flow environment. My current loop (Feeding Frenzy Interlude) has a bunch of 90's and 45's and my current flow is sitting around 165 LPH. If I were to ditch the restrictive flow meter I think it would go up to about 200 - 225 LPH, but then I wouldn't know.

[C'DaleRider]

Don't try to lie about he stated:


Those are his exact words. He sees 3/8" as the sweet spot and only to use 5/16" when you must for bends.

You may not value 1C, nor performance (which is obvious from your full Aqua Computer build), but most of us over here in XS are performance oriented. Many would pay a lot more for that extra 1.11C performance benefit. There's a reason why many of us jumped from 3/8 to 1/2 a few years ago and that was due to the 1.0C gain seen at the time. So yes, 1C is a big jump, which is why most of the WC'ing enthusiasts (people here at XS) purchase thermochill, Laing, Swiftech, D-Tek, etc products.

3/8" tubing itself results in minor .01C performance loss over 1/2" tubing, hence most of us won't mind dropping in size. However, low flow system, irrespective of tubing size, will perform worse. Low flow does not perform as well as high flow. You're using his data as a rallying cry for low flow systems as seen in your other posts; trying to misinform others by applying the 3/8" inch findings towards low flow setups in general.

How about you also stop trying to apply the tubing size findings to restriction overall. Elbows add restriction which hurts performance. More restriction leads to worse temps: http://www.xtremesystems.org/forums/...1&postcount=36


You want as much flow as possible to dissipate heat better within the radiator.

To further Cathar's analogy on tumbling vs. smooth flow of fluid through a radiator.....you can see a real world application in aftermarket transmission and oil coolers. Hayden, Perma-Cool, among others, incorporate within the tubes of their upper line add-on coolers, a system to tumble, or "turbulate" as they call it, the fluid. The swirling and tumbling of the fluid enhances the cooling effect of the coolers as more fluid is exposed to the tubes. So, very slow, low flow systems that ooze the coolant through the radiator are typically not as efficient in cooling as a swifter moving stream of coolant would be....just as Cather noted.

Of course, then there is the laminar flow problem that is likely increased as flow decreases. This only makes sense as the path of least resistance becomes the center of the tube as flow decreases......it is much easier for water/coolant molecules to stick to the tube's sides....henc emore flow is toward the center of the tube.

Granted, most of my experience with laminar flow problems is in the medical field.....in critical care areas (emergency room, trauma and life flight, cardiovascular and open-heart surgical recovery and critical care), but the same set of physics surely is in play within water/coolant tubing as is within the cardiovascular system in the body......just to a little lesser degree (red blood cells and platelets tend to be "sticker" than water molecules.)


I've found this thread fascinating....the immense amount of theory and information on radiator and tubing considerations is a fascinating read. Thanks for the continuing flood of information.


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

[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

[qdemn7]

Stew, I want to say thank you very much for your work. this makes me fell much better since i had been planning to install Colder NSH QD couplings for their flow rate. However they're rather expensive. It seems like the QD coupling that McMaster-Carr sells would work as well. Page 174.

[bito]

I have a bunch of John Guest Quick fit fittings/inserts here, all different sizes, from my old Swiftech days......now i have a use for them again !!

[Concorde Rules]

Nice work BUT it seems you didn't test in real world conditions!?

Things on paper rarely work out as they do in RL :P

Hell of a lot more testing, but would show once and for all the difference :/