Deionized (DI) Water

Not much out there that has quite the lore as deionized/RO/distilled water.

Using it to wash a car is fine. The only time that demineralized water (which includes RO and distilled) can be an issue is continuous flow of fresh water over a long period of time. If demineralized water was really an issue with your car then it would show up with rainwater.

Same applies to using it for cooling systems. It will not "eat" the inside of the system. A closed system is completely different than an open system.

Yes piping for demineralized systems should be polymer or glass. But it isn't going to eat away your car.
 
kschachn said:
Not much out there that has quite the lore as deionized/RO/distilled water.

Using it to wash a car is fine. The only time that demineralized water (which includes RO and distilled) can be an issue is continuous flow of fresh water over a long period of time. If demineralized water was really an issue with your car then it would show up with rainwater.

Same applies to using it for cooling systems. It will not "eat" the inside of the system. A closed system is completely different than an open system.

Yes piping for demineralized systems should be polymer or glass. But it isn't going to eat away your car.
Click to expand...
The metal drains in my story were chromed brass. But just for the sake of clear information, RO|DI dispensers are plastic. I have replaced faucets that were months old, because the previous plumber had piped RO into the existing new faucet, and they where leaking.

Why do you think that RO\DI systems should be polymer or glass? I agree, but how does that translate out to the statement that washing a car, would not hurt?

Honest questions. No doubt you are versed in this, genuinely interested.

Of course, industrial DI water and distilled rain water are two different things. Is this also incorrect?
 
In 1970 I was stationed at a SAC base in Michigan. We had a wing of KC-135 tankers. They used DI on takeoff to get additional thrust. I used to drive the DI truck and delivered it (warm) to the aircraft. The crew chiefs would dump the water on the pavement when it got cold. The water would re freeze on the pavement and make a slippery mess. We tested the DI by weighing a container with an analytic balance, filling the container with DI, boiling off the DI, then weighing the container again. The difference in weight represented the contamination in the water. The only problem with the testing was the test location. It was next to the runway and whenever a KC-135 or a B-52 took off the whole wooden building (especially the balance) would shake like a hula dancer. That did not improve the accuracy of the test.
 
burbguy82 said:
The metal drains in my story were chromed brass. But just for the sake of clear information, RO|DI dispensers are plastic. I have replaced faucets that were months old, because the previous plumber had piped RO into the existing new faucet, and they where leaking.

Why do you think that RO\DI systems should be polymer or glass? I agree, but how does that translate out to the statement that washing a car, would not hurt?

Honest questions. No doubt you are versed in this, genuinely interested.

Of course, industrial DI water and distilled rain water are two different things. Is this also incorrect?
Click to expand...
All water has a certain solubility for different metallic ions, if the water is not saturated then it can dissolve more, regardless of whether it is deionized, softened, river or ground water. So it is possible for any water to corrode piping depending on how soluble the metal is in that specific water. However, in most water piping systems the ions in the water will form precipitates and these can coat the piping to prevent further corrosion. Many things affect this behavior though, and it is why cites such as Milwaukee and Chicago closely control the pH of the domestic water supply so they don't leach a lot of lead out of residential water laterals. Lead laterals are quite common and were installed well into the 1980s.

So if deionized water with no minerals is continuously flowing over a metallic surface then it will continuously remove some of that surface. The water never gets saturated and there is no mechanism to passivate the piping to prevent corrosion. That's why DI water will corrode metallic piping given enough time and flow.

But you're only washing your car now and then. And beyond that the steel is coated with paint. If you had a jet of DI water spraying at the car 24/7 it might be different, but not for even frequent washing. There is so much else in the environment that is simultaneously attacking your sheet metal that the infinitesimal effect of the DI water is truly lost in the noise. Besides that a detergent generally is alkaline (not automatic car washes).

Any water that has metallic ions removed is deionized water. RO does that, a DI resin bed does too, or if you distill the water. Water softeners also remove certain metallic ions but they are replaced with sodium ions (or sometimes potassium). That is an ion exchange which is different than DI water. Rainwater is distilled water but it can pick up stuff on the way down depending on the local environment and depending on how long it has been raining. As a result rainwater is very low in minerals but can have a low pH due to environmental contamination. It's not as much a problem as it used to be years ago but low pH water can definitely attack paint.

Closed systems such as an automotive cooling system quickly become saturated and no longer leach metal from the engine. This is on the order of micrograms anyway. And the coolant has buffers to help prevent corrosion. Sometimes you see websites claim that DI or RO or distilled water will corrode a cooling system because the water is "hungry" for ions. This is a good illustration of someone knowing a little and then extrapolating that to a general truth which is incorrect.
 
One thing about the drains is they see a lot of acid and caustic when regenerating. Water is the most active solvent but is almost immediately neutralized after being made. It will absorb silicon out of glass if just made.
 
When they make RO bottled water some they add a slight amount of potassium bicarb to it to take the 'charge' out of the water so it won't alter the taste perception. Or give a metallic taste.
 
SHOZ said:
One thing about the drains is they see a lot of acid and caustic when regenerating. Water is the most active solvent but is almost immediately neutralized after being made. It will absorb silicon out of glass if just made.
Click to expand...
How is water neutralized? Do you mean saturated?
 
kschachn said:
How is water neutralized? Do you mean saturated?
Click to expand...
Any water that has been 'made' for more than a few seconds is neutralized, no electrical charge. Rain pulls N, C and O out of the air. Saturation and a solvent is a whole different subject.
 
kschachn said:
if the water is not saturated then it can dissolve more
Click to expand...
Right, which is what I was saying. When you wash a car, that water will get into many cracks and crevises, and sit. The stuff does not immediately evaporate.
kschachn said:
This is a good illustration of someone knowing a little and then extrapolating that to a general truth which is incorrect.
Click to expand...
Sure it happens all the time, but it stand to which that washing a car, in the same fashion you would regular water, could not be a good thing, especially if the water collects near an electrical connector.

Of course I am not saying that the car will rust day one, I am simply saying that DI water can be more damaging than just regular tap water, which it is.

I did forget to mention this in my story. At first, I did not believe the guy, about the corrosion. He took me to the maintenance shop where there was a 6'' clevis hanger, which was dripped on by the water, from a leak. It looked like Xenomorph acid had eaten it. Sure it was over some time, but it was amazing to see the damage. Plastic hangers are not available in that size, nor are they strong enough to jold a full 6'' SCH80 pipe full of water.
SHOZ said:
One thing about the drains is they see a lot of acid and caustic when regenerating
Click to expand...
The drains in my story do not see any acid. Water from these sinks go right back into the distribution system after treatment. Acid drains where a completely different system, with come crazy clear pipe I had never messed with before, they provided it. It went to a tank, neutralized, and into the sanitary sewer.
 
burbguy82 said:
Right, which is what I was saying. When you wash a car, that water will get into many cracks and crevises, and sit. The stuff does not immediately evaporate.

Sure it happens all the time, but it stand to which that washing a car, in the same fashion you would regular water, could not be a good thing, especially if the water collects near an electrical connector.

Of course I am not saying that the car will rust day one, I am simply saying that DI water can be more damaging than just regular tap water, which it is.

I did forget to mention this in my story. At first, I did not believe the guy, about the corrosion. He took me to the maintenance shop where there was a 6'' clevis hanger, which was dripped on by the water, from a leak. It looked like Xenomorph acid had eaten it. Sure it was over some time, but it was amazing to see the damage. Plastic hangers are not available in that size, nor are they strong enough to jold a full 6'' SCH80 pipe full of water.

The drains in my story do not see any acid. Water from these sinks go right back into the distribution system after treatment. Acid drains where a completely different system, with come crazy clear pipe I had never messed with before, they provided it. It went to a tank, neutralized, and into the sanitary sewer.
Click to expand...
If you really believe that deionized water is getting into the cracks and crevices and causing your automobile to corrode away over time, then I really don’t know what to tell you other than you better not drive it in the rain.

Crazy stuff.
 
SHOZ said:
Any water that has been 'made' for more than a few seconds is neutralized, no electrical charge. Rain pulls N, C and O out of the air. Saturation and a solvent is a whole different subject.
Click to expand...
So your water purification system makes water? I had no idea. I guess that explains a lot.

After the rain pulls those elements out of the air, then what happens?
 
kschachn said:
If you really believe that deionized water is getting into the cracks and crevices and causing your automobile to corrode away over time, then I really don’t know what to tell you other than you better not drive it in the rain.

Crazy stuff.
Click to expand...
rain and DI are very different of course
 
Ok, I ordered a cheap TDS meter.

IMG_0393.webp


Looks like my water is hard, but not as terrible as originally anticipated.
 
kschachn said:
So your water purification system makes water? I had no idea. I guess that explains a lot.

After the rain pulls those elements out of the air, then what happens?
Click to expand...
My water is from my well. Drink it unfiltered. I also collect rainwater. Rainwater laden with elements that are not volatile and evaporate will be left behind as deposits.

Rain water has a nitrogen, oxygen and CO2 in it . Great for plants. The TDS of the rain water around here is generally in the 15 ppm range, pH 6.5 or so.
 
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