That poor pump location wasn't all bad. At least I took a good shot from
there showing how you can go about approximating the bend radius of your tubing.
Please note that you really need to plan, plan, plan how you are going
to route and bend your tubing. Follow the measure twice, cut once, rule...and
plan.
Tubing
Example Of Tubing Bend Radius
Tubing comes in a wide variety of wall thicknesses, rated bend radii, and
various other temperature and chemical tolerances. Also, there are three major
I.D. (inside diameter) sizes that you can use (1/4", 3/8" and 1/2"). I used 1/2"
I.D. tubing as it allows for better flow rates than smaller I.D. tubing
(especially 1/4" I.D.). More water means increased capacity for heat absorption
and more GPMs (gallons per minute). You'll usually not want to mix different
tubing sizes as the smaller sizes will lower your flow rate.
McMaster-Carr is a great site to read up on all kinds of tubing.
In the photo above, notice that I don't have the tubing actually on the barb. It really depends
on your tubing but as a general rule, once you place the tubing fully on the
barb it can be very difficult to remove. It can be done, but you'll likely stretch the
tubing out of form or have to cut it off the barb. So, you need to take the
offset into consideration as to how it will affect the tubing length you'll
really need once it is on the barb. You could just partially place the
tubing on the barb and that does work as well...but you still need to take into
account the difference from being fully on the barb.
I ended up having about 5 feet of total tubing length in
my circuit. However, I burned through a lot more than that in the process. I
would suggest that you first approximate how much tubing you'll need, double it, and order that length.
I used three different kinds of tubing: Tygon® R-3603, Tygon® R-1000,
and generic from Home Depot. The R-1000 was the softest and I would not
recommend it for sections in your circuit that are longer than a few inches or
that feed into your pump. For example, the photo below shows how strong the
suction from the PolarFLO pump was...enough to fully collapse and twist the
R-1000 tubing.
Example Of Tubing That Is Too Soft (R-1000)
This other example below was elsewhere in the circuit but the run was too
long, which caused the flattening shown. This is the stiffer R-3603 tubing
though. What is interesting is that initially it held a uniform diameter.
However, after a few days it began to flatten. Something called "CoolSleeves"
would have solved this. CoolSleeves are the blue spiral PVC you see around the
tubing in the photo above. They act as kind of an exoskeleton which gives the
tubing greater bend radius capability and more strength to maintain its shape
in curves.
Example Of Tubing In Need Of CoolSleeves
The photo above may seem a bit nit-picky as it isn't a full collapse or kink
of the tubing. However, that slightly flattened area can still be enough to
affect your flow rate in a negative way.
What surprised me is that I eventually ended up using much more of the
cheaper, generic tubing from Home Depot. I bought a 15 foot length for just under $4
(compared to around $3 per 5 foot of Tygon® tubing online). This generic tubing was
stiffer which allowed for some of the longer runs I needed to make. It also fit
onto the barbs much more snugly than the softer R-1000 tubing.
Connecting Tubing To Barbs
I tried various methods of connecting and securing the tubing onto the barbs.
You don't have to use anything but most people like the added security of
a clamp. Some people swear by plumbing hose clamps (the metal kind with the worm
screw). Other folks like the plastic push clamps. I finally decided on (and now
greatly prefer) using the beloved zip tie. In some cases, though, I didn't use
anything. I simply put the tubing on the barb and let it be.
Various Hose Clamps
The main problem I had with all of the clamps is that they aren't perfectly
uniform around the circumference of the tubing. You can see in the photos below
that there will always be some kind of gap where the clamp doesn't make full
contact and that is where you can actually cause the source of a leak that
wouldn't have been there otherwise.
In the photo below you may also notice that I wrapped a layer of duct tape
around the tubing to help prevent the metal hose clamp from cutting the tubing
(another potential problem if you aren't careful).
Example Of Gap With Hose Clamp
The plastic clamps are okay, but they basically have to be cut if you want to
remove them. I also never felt satisfied with how tight I could get the plastic
clamps to lock. Even if I used pliers to squeeze the teeth tighter they would
never hold as tight as I wanted; they would slip back to a looser notch.
Example Of Gap With Plastic Clamp
The simplicity (and cheapest cost) of zip ties wasn't the only thing that won
me over. Their size and effectiveness (especially when alternated in a pair) was
excellent. What I mean by "alternating in a pair" is shown below. I decided to
nullify the gap that a single zip tie had by using a second zip tie. I offset
the second zip tie so that its connection point was opposite that of the first.
This way, there really was no gap.
Example Of Zip Ties
Zip ties were also used out of necessity when it came to the three barbs of
the PolarFLO TT Series CPU water block. The three barbs are so close together
that zip ties are really the only securing mechanism that would fit.
Tight Squeeze
What I finally settled on for the CPU water block, though, was to not use
clamps at all. I eventually ran out of CoolSleeves as you can see in the photo
below. Despite the potential for reduced flow from the flattening, my cooling
results were still excellent.
