Pseudo Partial Pressure Blending using HP 300 cuft rented tank?

[Basking Ridge Diver]

What does this mean. Your compressor is not providing air at 0 ppm CO2. There must be a typo.

Sorry what I meant to say was the air is 0 ppm every time I have test it...

The compressor has an X-pendable filter cartridge. But I dont see anything on the HP side...

 

[RayfromTX]

What are you saying is measuring at 0 ppm and what do you mean by you don't see anything on the HP side.

 

[Basking Ridge Diver]

What are you saying is measuring at 0 ppm and what do you mean by you don't see anything on the HP side.

There is 0 ppm CO.

@tbone1004 said earlier - "The air cleaner doesn't really matter, it's the filter stacks at the end of it." I was looking to see what type of filters were on the compressor. So coming out of the compressor filling 6000 PSI - is what I call the HP side.

 

[Basking Ridge Diver]

Just to come full circle - I created my first batch of 32% nitrox today. It ended up being 31.6% but my target was 3000 PSI and I went to 3200 PSI thinking since I was going to test it I wanted to overfill. So I know why I was off and what to do next time.

The Voodoo Black Magic mystique really got to me. It took several hours and maybe even a full day before I got the nerve to connect the O2 and actually flow the gas. The needle valve really only wants a crack - so I filled too fast at first but I am getting used to the gauges and the valve.
I did not burn down the shed or blow anything up and now I feel a bit better about having done it...

Thank you to those that offered guidance and opinions - I needed to hear it and I had to try for myself in the end.
This should be the beginning of $1.05 fills for nitrox...

 

[dberry]

This is an interesting explanation about OCA and analyzing it properly:
Oxygen Compatible Air

 

[Basking Ridge Diver]

This is an interesting explanation about OCA and analyzing it properly:
Oxygen Compatible Air

Thank you I read it and it reminded me of - paralysis by analysis is the state of over-analyzing (or over-thinking) a situation so that a decision or action is never taken, in effect paralyzing the outcome.

I think this is one of those times I (you the reader of this thread) need to understand as best I can (read up on the subject by those doing it and the "experts") - take into consideration your risk tolerance (there will always be someone saying not to do something) and deciding if it is worth the risk - keeping the process as clean as possible and transferring any O2 as slowly as possible. My understanding is most of the issues have been when introducing O2 into the compressor and or knocking over 100% O2 tanks being stored - I am doing neither. I am working with 100% O2 and need to apply safeguards and common sense as well as trying to ensure the process is as clean as possible.

I also believe a dive shop versus a private citizen has more at stake - poor PR and potential for lawsuits is extremely high in my opinion - all leading to a business downturn.

I will endeavor not to end up in the Accidents and Incidents forum...

 

[TrimixToo]

Just to come full circle - I created my first batch of 32% nitrox today. It ended up being 31.6% but my target was 3000 PSI and I went to 3200 PSI thinking since I was going to test it I wanted to overfill. So I know why I was off and what to do next time.

The Voodoo Black Magic mystique really got to me. It took several hours and maybe even a full day before I got the nerve to connect the O2 and actually flow the gas. The needle valve really only wants a crack - so I filled too fast at first but I am getting used to the gauges and the valve.
I did not burn down the shed or blow anything up and now I feel a bit better about having done it...

Thank you to those that offered guidance and opinions - I needed to hear it and I had to try for myself in the end.
This should be the beginning of $1.05 fills for nitrox...

What went wrong? I can't tell yet. Let's start with: How long did the mix sit before being analyzed? Did you roll the tank, or put it in the trunk of your car and take a spin around the block before analyzing, to mix the gas more quickly than mere diffusion will accomplish? How did you determine the required O2 pressure? What was in the tank when you started? Do you get the same analysis result a day later?

Also, there is no need to overfill a tank you are testing if the flow rate to the analyzer is within reason. You won't lose enough pressure to matter. A flow restricter or other means of achieving the desired flow rate (for my analyzers, 1-2 l/m, IIRC) is indicated.

(Hey, did you know there's a course for this? I can't say a course is required to learn to blend successfully and safely, but being taught improves the odds of staying clear of "that other forum," IMO.)