Large amount of rust in 2nd hand steel tanks and can rust be transfered via DIY 6 way manifold? + improving MCH 6 for long fills

[Kriss1]

So, here's an interesting one:
Can rust be transfered via whip/compressor manifold? For my example I've made DIY 6 way manifold.
So recently I turned my old 18L steel twin tanks into singles and by just turning the tanks upside-down roughly 50 grams of rust poured out of each tank. I don't have good picture of the manifold but I got something.
I'm not worried about the tanks containing rust but rather the new tanks.
Also here's the picture of the rust that came out of the tanks.

Another question is which way should I go about cleaning the tanks whip or thumble?

To Clarify:

As for people asking do I clear water from the valves before fills yes I do in 2 steps first without the filling end I always blast the tank valve open for a second or 2 and 2nd before opening the compressor valve I also bleed air from the bleed valve for few seconds.

So as for additional information:
The compressor is MCH 6, and yes, I was filling 8 tanks at a time.
I have PMV set @180 bars.
Never have I exhausted filters all the way to the point where the strip indicates that the molecular sieve is no longer able to absorb the moisture
And most important of all is that these are the only tanks that I've bought 2nd hand and they re 10 years old, was going for hydro test which is why I was doing visual.
As for the comments about me burning thru the filter fast cus it's 8 tanks connected to the compressor check my previous thread which I asked question why I should only run the compressor only max of 1 hour at a time. Which I've been doing. (also I have automatic condensate removal 5 mins - 2 seconds)
On that note about the heat killing the filters I will post an update @ some point in september.
I'm building a system add on system (arduino based) that will:
Monitor the oil temperature + motor temp.
Monitor the hours running since filter swap.
Monitor the motor current/voltage incase of belt failure
Monitor the output pressure + current as current goes up from 180 bar to 330 bar 12.5-15.2A should the pressure sensor fail.
Switch the compressor ON/OFF to allow it to cool between cycles.
Turn off the compressor should anything go wrong.
On top of that I have 400mm ~400w additional fan to cool the compressor during filling + on cool down cycle.
(also controlled by arduino).
+ few more failsafe features.
Based on my logic with additional cooling from the fan during off cycle ~ 20c ambient temp. I should be able to run it 45 min on/15 min off with active cooling.
Also what even fails if I were to fill for several hours? Assuming I replace the filters/oil in time.
In my recent test I attached temp probe to the end of the oil rod which is perfect indicator of the pumps operating temperature with additional fan and control run with built in fan.
Here's the results: 18c ambient temp.
Control run:
With original fan the oil temperature stabilized after just 10 minutes @55c (PMV set to 200 bar for that test for consistency)
2nd run with additional fan added to the mix: oil temp reached max of 48c under 10 minutes and stabilized @ that point.
So if I'm able to keep the temperature down what gives?

 

[iain/hsm]

So, here's an interesting one:
Can rust be transfered via whip/compressor manifold? For my example I've made DIY 6 way manifold.
roughly 50 grams of rust poured out of each tank. I don't have good picture of the manifold but I got something.

It just has to be a Coltri MCH 6 What else could it be. The divers favourite problem.

1. Did you fit non return valves at the ends of your 8 filling whips and inline filters upstream ? Yes/No
2. Depending on if you fitted non return valves and in-line 15Mu filter the answer to the first question is Yes/No

Yes you can transfer (dry) rust from cylinder to cylinder without the two items above
The 15Mu particulate in line filter is always fitted up stream of the check valve or non return valve.
For two other but different reasons.
The filter protects the soft seat of the non return valve from "peppering" basically molecular sieve off the chemical filter blasting out the soft polymer seat of the non return valve

Now if its wet rust its pretty much always from the compressor, water carry over, blocked drain valve lack of draining often enough, Faulty BPR leaking at low pressure,
Cheap imported Chinese molecular sieve is a favourite of mine especially those who buy cheap aftermarket filter cartridges when they have no idea what chemical quality is used.
Chinese molecular sieve made for the double glazing market and activated carbon made for the fish tank aquarium market are the main culprits and favourites of the scuba compressor industry.

But you biggest problem by far is the Coltri MCH 6 compressor itself.

 

[Wallowa]

It just has to be a Coltri MCH 6 What else could it be. The divers favourite problem.

1. Did you fit non return valves at the ends of your 8 filling whips and inline filters upstream ? Yes/No
2. Depending on if you fitted non return valves and in-line 15Mu filter the answer to the first question is Yes/No

Yes you can transfer (dry) rust from cylinder to cylinder without the two items above
The 15Mu particulate in line filter is always fitted up stream of the check valve or non return valve.
For two other but different reasons.
The filter protects the soft seat of the non return valve from "peppering" basically molecular sieve off the chemical filter blasting out the soft polymer seat of the non return valve

Now if its wet rust its pretty much always from the compressor, water carry over, blocked drain valve lack of draining often enough, Faulty BPR leaking at low pressure,
Cheap imported Chinese molecular sieve is a favourite of mine especially those who buy cheap aftermarket filter cartridges when they have no idea what chemical quality is used.
Chinese molecular sieve made for the double glazing market and activated carbon made for the fish tank aquarium market are the main culprits and favourites of the scuba compressor industry.

But you biggest problem by far is the Coltri MCH 6 compressor itself.

Man you really, really dislike MCH6 compressors! Not clear what exactly are their weaknesses that you distain so much.

"It just has to be a Coltri MCH 6 What else could it be. The divers favourite problem."

"But you biggest problem by far is the Coltri MCH 6 compressor itself." Why?

Back to rust....Kriss...you said: "So recently I turned my old 18L steel twin tanks" and out came that huge pile of rust...I have never seen that much rust even after tumbling steel bottles...that was impressive amount! Did you visual those tanks recently before dumping out that corrosion? Could the bottles have had a long time to build up that rust and never been noticed? Were the bottles left without pressure and valve open in high humidity environment? Not sure how the rust can be attributed to intake of moisture coming from the compressor. Keep us posted when you find something definitive.

 

[Tracy]

Man you really, really dislike MCH6 compressors! Not clear what exactly are their weaknesses that you distain so much.

"It just has to be a Coltri MCH 6 What else could it be. The divers favourite problem."

"But you biggest problem by far is the Coltri MCH 6 compressor itself." Why?

Not to put words in his mouth, but I can help answer.
It isn't a good compressor, it never was, and never will be. It is a cheap compressor.

Nobody in history has purchased one because they think it is an excellent unit.
It is purchased because it is the cheapest option on the market.

It is functional and cheap, those are the only redeeming qualities for the unit.

 

[Wallowa]

Not to put words in his mouth, but I can help answer.
It isn't a good compressor, it never was, and never will be. It is a cheap compressor.

Nobody in history has purchased one because they think it is an excellent unit.
It is purchased because it is the cheapest option on the market.

It is functional and cheap, those are the only redeeming qualities for the unit.

Not trying to get in anyone's space...but can you give specifics why this is a poor choice of a compressor to purchase?

"cheap" , "cheapest" and "functional but cheap" really does not speak to why "it isn't a good compressor".

Again, not disputing your opinion, but I deal in facts and details so would appreciate why this is not a good compressor. What specifically are the short comings of the MCH-6? Anybody?

Thanks...

 

[Tracy]

Not trying to get in anyone's space...but can you give specifics why this is a poor choice of a compressor to purchase?

"cheap" , "cheapest" and "functional but cheap" really does not speak to why "it isn't a good compressor".

Again, not disputing your opinion, but I deal in facts and details so would appreciate why this is not a good compressor. What specifically are the short comings of the MCH-6? Anybody?

Thanks...

The entire design is a shortcoming. Inadequate cooling, inadequate lubrication, inadequate separators, inadequate filtration. It is designed to be cheap, not good.

 

[Scuba-guy]

I was going to buy the MCH-8, is that one ok?

 

[Tracy]

I was going to buy the MCH-8, is that one ok?

I'm not familiar with that pump. I would have to see it as I would almost guess it is an mch6 block spinning even faster. It could be an mch13 turned down a bit and that would be a decent pump.
But best of my knowledge the mch13 was replaced by the mch16 turning slower. That makes me doubt they are turning it clear down to 8 m/h.

 

[Wallowa]

The entire design is a shortcoming. Inadequate cooling, inadequate lubrication, inadequate separators, inadequate filtration. It is designed to be cheap, not good.

Well that blanket condemnation, "entire", pretty much covers it! No use in asking for an elaboration and details. Just too bad for those using the MCH-6...

 

[Scuba-guy]

How about L and W?