I would imagine 30-60 seconds would have ur oil lookin nice and golden....I also thought the return would be a lot better...I did 36 grams with butane and got 4.5 grams,I'm gunna run 36 grams this weekend with the iso and see where I am at...
That yield is low but not outside acceptable bounds depending on source material--this could be about tube design/operation as well.
There is much ado about durations here for both QW and tube extractions. The truth is that there is no specific time that is the right time. Due to the complex structures at play here there are many paths that can be taken for the molecules. Some of these are longer and others shorter. This is ESPECIALLY true for tube type extractions which is why getting it wrong is sometimes worse than not doing it at all.
With liquid contact on the solvent you're getting almost everything out.
In my opinion if source material amount isn't a huge issue (ie you have qp to burn) the best way to QW would be by doing maybe a 3-5 second VIGOROUS wash. Use something to add your solvent with a wide opening that pours quickly and pre determine the amount of solvent you will use.
Perhaps use some mechanism whereby the bulk material can be removed very rapidly after washing rather than letting it sit and equilibrate further, even for a second or two, as it filters. Something like a removable basket to yank the bulk out. Depending on your filter setup this might not be necessary. The idea here is to get something nearest to pure as you can, so think sacrifice to yield for this step (use chilled solvent/frozen buds).
Following that do 2 further washings of the bulk/filtrand but this time shake vigorously for maybe 25-30 seconds. Combine the 2nd and 3rd washings for a more crude product (or keep them separate).
For my taste this would be a small scale extraction (to increase speed). Tiny jar, small amount of solvent, quick filtration. If you do it this way and get maybe say 10-15 first runs you can have your pick of them based on color and combine them accordingly--you can also get some data out of it if you're using the same weight of starting material and same volume of solvent. You can also choose based on color which of the subsequent washings to combine. It's a bit more clunky for sure, but this gives you a bit more control--and a better tolerance for error.
Determinant error is a huge factor in lab steps which require fast motions. So much so that many times these are automated by machine in labs. So while many people argue about what time to use and which various extraction is the best--there won't be any good data if everyone hasn't been using standardized techniques/instrumentation.
It's like having an argument without first agreeing what the scope of the argument is. I think Aristotle said that's bad or something.