Still parting together my setup and am trying to figure out the best type of 1/4 hose for G18 connecctions.
I’ll have stainless steel bellows from my pump to a T which will have my vacuum meter on the top, stainless steel bellow going to the cold trap where a GL18 to KF25 converter is located.
Read a lot of people saying that a lot of vacuum lines are semi-porous so I’d like to get peoples take on that and hear some suggestions. My line will only be about 10".
Almost ready to go… material for distillation is almost prepped and just waiting for a few things to come in the mail. Gotta get my PID setup so this damn Chinese mantle can operate better.
Hands down Nalgene vacuum hose is my highest recomendation. It is autoclaveable and the ¼ ID Nalgene hose has thick ¼ invh walls. It cuts with paper scissors and stays in place. The thick walls help keep small gas atoms from penetrating very fast. It cost me $17.00per foot and my supply is no longer there but at least you can see what it is. It is worth it with ease of use. I ordered ten feet and wint run out soon. It is durable. https://www.amazon.com/gp/product/B008P1872E/ref=oh_aui_search_asin_title?ie=UTF8&psc=1
Theres a high temp, vacuum silicone clear hose on amazon, most of us have used for years… the benefits are that it wont break down, holds good vac, doesnt care about temperature, and its seethrough so you can see clogs and anything that can harm your vacuum depth. You can also soak in ethanol to clean… that way you get alot of uses from the same tubing
I like to use that thick silicon kind for buchner filters etc. Its super elastic and doesnt get “blown out” when u put it on a barb and take it off over and over. I also use it for the feed tube for the rotovap.
I tested a lot on every part of my hobby. The fun is in learning the litle things that make it seem more like a medicine man sort of thing than just pure hard work to make it work and earn a living.
I did a series of four labs. Each video sucked so the are trashed but easy enought to test.
I took 12" of silicon based vacuum hose and 12" of Nalgene. The test was unfair a bit because tube wall thickness has far more impact for a few different reasons than most realize. Here was my test:
I put my pyrani based sensor at the end of the nalgene hose and connected that dirrectly to the blank off at the pump. I pulled vacuum and noted how fast it pulled down and how far.
I also did the test with a forline trap installed and the results were profound!
The second test was the same length hose but was some polymer meant for vavuum. Big difference! The Nalgene in a dry mock up system pulled down to the pumps rated ultimate vacuum rating in under 30 seconds and held it rock steady. The plain jane polymere took much longer to pull down and was under 20 microns but clearly not as good as Nalgene. The real surprise was my foreline trap… correction, my boat anchor now… because it could not pull down to ultimate with either and both hovered around 20 microns.
I know why this happens because the trap is designed to absorb then retain oil from the pump motor that attempts to back flow up the vacuum line. Downside is the oil becones contaminated and then loses the ability to pull a hard vacuum given that we have such terpenes present. Those terpenes are always evaporation o long as you can smell them. So even a cold trap revealled a loss of system vacuum when used.
The other tip for hose is the smell of if Any odor at all indidates volatile compounds are evaporating and then the vacuum takes a hit. I have a rubber sealed bell jar vcuum chamber. One hour at 5 microns and it mells like a bicycle tire repair shop lol.
A final test I did was to take contaminated oil and run it through my verticle SPD. The oil stayed in the flask and the volatiles came across but then the temp needed to get the oil fraction exceeded my safety zone so I stopped. The lesson though was watchnig how low the temp had to be to get boiling in dirty vac oil under vacuum distillation. Lesson is that even with best equipment you must keep you vac oil changed to maintain deepest vac possible.
