lets ALL figure out the fogging of tubing issues!!!

[Snyxxx]

I know 3603 will still "fog" even with pure distilled.

I know there is a post somewhere in here about a piece of 3603 placed into a cup of distilled water. A week later it was fogged. Remove from water and let it air dry, no more fog.

I think it is water absorption by the tubing that makes it look "fogged". I put a lot of heat intop my loop with only a PA 120.2 and maybe that affects this absorption rate in comparison to those of you that do not notice this with pure distilled.

Mine always fog eventually.

[sfxs]

For 2 years and 2 months (Dec. 07 to Feb 09) I ran the following loop:

Iwaki MD20RLZT (Polypropylene)
Cast red brass reducer coupling
Kynar (aka PVDF (Polyvinylidene fluoride)) plastic barbs / tee / couples
AquaXtreme MP-05 LE (nickel, copper, Delrin (Polyoxymethylene plastic))
Swiftech MCW50 (copper, Delrin (Polyoxymethylene plastic))
Nickel plated yellow brass barbs
Thermochill PA120.3 (yellow brass?)
Masterkleer 7/16" ID tubing (PVC, other?)
Distilled w/ PT_Nuke (CuSO4)
All components were cleaned/flushed with an OCD-level of clean - 3 sets of 18 hr soaks in vinegar/water solution with water flushes over 1 week for the radiator, as an example.

So a material breakdown of that is:
Nickel, copper, red brass, yellow brass, Polyvinylidene fluoride, Polyoxymethylene plastic, PVC, whatever else is in Masterkleer tubing, and CuSO4.

The entire loop was closed in a steel case with nil for external light. Here are my observations:

1. Tubing began to cloud ~1 year into use.
2. Only the loop clouded, not the stationary water in the fillport line.
3. Tubing noticebly cloudier ~ 2 years into use.
4. Fillport line still crystal clear.

I did have to top up the system every ~6 months - about 2 fl. oz. worth.
Math Warning: 6" roughly of the tubing (7/16") ~= 3.6 cubic inches of water. IIRC ~= 1.8 cubic inch to a fluid ounce.

Total water "consumption" ~ 1/3 of a fl. oz. per month.
When emptying the loop, the water was not cloudy, and the tubing remained cloudy even after flush & brush).

My Opinion: There is a reaction with the tubing, water, and light. My tubing clouded far slower than similar loops that were exposed to light (from my reading of the forums). The cloudiness was a result of water evaporating through the pores in the tubing, bringing with it various impurities resulting from the components in the loop - or, evaporation exacerbated by the pressure in the loop portion of the tubing as compared to the fillport line.

Final Thoughts: Cloudy tubing is an aesthetic issue only. If you absolutely must have clear tubing, find something non porous ( $$$), or change your tubing every ~6 mo. ( elbow grease). Also, the less you look at the tubing (less light), the clearer it will be ().

The opinions expressed above do not reflect any expertise in chemistry, or maybe any science at all - someone else have at it.
-sfxs