My question is if there is a certain way you go about when mixing gases specifically doing a 70/30 mix. Ive heard there is no direct literature per say, just that it is recommended filling with the lowest pressure gas first (butane) and then mix with higher pressure gas (propane) also can you mix and transfill in a non jacketed tank? Im hearing different things from different people. thanks in advance for advice.
Your going to mix your own? Why not juat buy it already mixed?
3 Likes
Agree with slabby, just get a tank that’s pre blended. Lmk if you need any help with that
im using a closed loop system for a large wholesale grow, so we have to transfill as needed when the tank gets empty or close to empty. Im new to all of this as well so everything has been and still is a learning experience. heres a pic of the closed loop sytstem I am
using. One tank is jacketed, the other is not. Uploading: 20190806_085717.jpg…
Its only that mix once, every run will change it. It will start to be more propane dominant
1 Like
what do you mean? please elaborate.
Propane boils first. Eventually the butane left in the material will throw off ratios
1 Like
Its only 70/30 the first time you use it, everytime after it will become more burane nominant
So do most people eye ball it when filling an empty tank to 70/30? Also any answer on if it is safe to move gas from the large jacketed tank, through the closed loop sysyem to distill the gas, and into the new non-jacketed tank?
Im assuming most people buy a 70/30 blend if thats what they want. I have never heard of anybody mixing their own blends. I dont want to sound like a dick so please dont take it that way but of you have to ask these questions about of its safe and dont know the answers you shouldnt run that cls… Thats alot of cls for someone thats learning.
As long as your system is properly vacuumed down then there is no safety issue
1 Like
I’m asking for extra clarity for a fellow employee that is also running it who is convinced it is unsafe, even after the company that sold us the cls specifically stated it is completey safe after our manager emailed asking them. Ive been running this cls for a few months now and feel confident in being able to run everything. Just trying to get solid info for a friend. but yes we are all still learning and new in the industry. The company who sold us the cls are suppose to come back out soon for more training, was just trying to get ahead with info thats out there.
Ok… Why would transferring from one tank into another be unsafe? The jacaketed stuff has nothing to do with anything. Its 2 tanks. He seems like he shouldn’t be working there.
Side note. Ets setups are always so pretty.
1 Like
You can certainly mix a blend yourself safely. I used to do this when I ran out of 70/30 but had butane and propane on hand. Take an empty tank, vac it down, fill with butane first, then propane. For examples sake, say you have a 20lb tank (empty) that holds 20lbs of solvent, 40lb total weight (full). 20lb x .7 = 14lb, there’s your 70% butane. The other 6lb will be propane (30%).
You add the butane first and the propane last since propane has the higher vapor pressure and is lighter, it will sit on top of the butane, they do not mix and create an azeotrope, so they will never boil at the same temps.
But yes it’s much easier to just buy the mix.
Edit: Just thought I should note that LPG tanks have their tare weights on them, and if you’re using/filling tanks I would suggest using a refrigerant scale to accurately measure your solvent.
what i meant was can you distill gas through the system and into a non jacketed tank?
I know what you meant. My reply was in regards to that.
Liake i said yesterday its safe. Just vacuum everything down in the system as normal and handle biz
1 Like
You could definitely distill gas thru the system and recover into a non jacketed tank, no problem. If you have a bucket large enough to fit your tank in it makes it much easier (water bath). If you don’t have anything to use as a water bath then you’ll have to resort to raw ambient pressures, connect your recovery line to the dip tube valve and relieve pressure from the vapor valve, you lose way more solvent this way though. Much better to cool your recovery destination.
Honestly though, seems easier to just start with an empty tank, add your butane, then your propane, and then distill it. And even easier to just buy a pre-blended tank, like @slabby said.
This is close, but not correct as far as I am aware. The mixing instruction are fine, but the explanation is not quite.
Butane and propane do mix, but just not as an azeotrope. As they are a mixture composition the mixture will boil together, the total vapor pressure of the mixture is equal to the sum of the individual partial pressures. More propane dom mix = closer to propanes bp, while if it has more butane the closer to butanes bp will the mixture be. If they didnt mix youd run the risk of only injecting butane if your mix was 70/30 and only injected half your tanks worth.
That is why this chart from the tool box is titled "Propane Butane Mixtures - Evaporation Pressures - Propane Butane Mixture - Evaporation Pressure
Raoult’s Law and Ideal Mixtures of Liquids:
3 Likes
@pangea Yes, you’re absolutely correct. This totally slipped my mind, and apologize for spreading any misinformation! What I meant by “they don’t mix” is that it seems like the propane recovers before the butane, as the beginning of a 70/30 recovery is usually faster than the latter half. But this is all anecdotal on my part, I ain’t a scientist so my word ain’t law. 
1 Like
thanks man this helps alot
1 Like
thanks for this info guys