We pump down between passes, so after 5 passes, the butane level in the lower collection tank would be the same.
This is confusing to me because I'm following the procedure from the MK III post on the SPR website. I've pumped it down to -10" Hg between floods and the butane level most certainly rises in the collection pot with each cycle. When you say "pump down" between passes do you mean I should let the gauge go until it reaches -22" Hg between floods.
Please change the silicone rubber gaskets in your site glass to Viton. Silicone rubber absorbs butane.
Wilco Gray Wolf. Does anyone know if there is a local source in the San Francisco Bay Area for Viton gaskets?
Amber after 5 passes begs more information. We typically clear the material and yield 20% at 3 to 4 passes.
How long are you allowing it to soak?
Again, as I stated above the "soak time" has been dictated by length of time it takes the gauge to reach -10" Hg. The first cycle is fast and takes a minute or so to pump down, each subsequent flood cycle takes longer. I can complete a 4 flood cycle run in less than an hour. Which seems fully in-line with what I've read, and what Carla showed me when I was there, and what I expected.
We examine the spent material under a microscope, to tell whether we are getting it all or not.
I brought the USB scope home so that my 5 year old could play with it. I'm taking it in today and will take a look. I've been contemplating making a video to show step-by-step what I'm doing.