So why is mixing by weight better than mixing by volume?

[Ed Brown]

I've been mixing liquid for close to a year now and have been mixing by volume, with various graduated cylinders, and recently, syringes for the small measurements.

Full disclosure: I'm a water/wastewater engineer and calculate feed rates, dilutions, volumes, and weights all day long, using metric and English units. I can figure out how many liters/hour of a chemical of a given concentration must be added to treat a stream of millions of gallons/day of water to achieve the required final concentration. Calculations with water based systems are convenient because one liter of water has a mass of one kg. Certain shortcuts can be employed due to this fact. Not so fast with English units.

We buy nicotine liquid that is measured in mg/ml (mass/volume) of solution, not mg/kg (commonly called % by weight) of solution. The final product is also expressed in mg/ml (mass/volume) not mg/kg of solution. As long as the total mg of nicotine is properly measured and calculated, and the total volume of product is properly measured and calculated, the results are perfectly accurate (at least in the spreadsheet).

The only aspect where % by weight would be useful would be in calculating VG/PG ratio. Since the specific gravity of VG and PG are pretty close, the results of a volumetric calculation seem close enough. Who really cares whether the VG/PG ratio is 75/25 or 75.3/24.7? Measuring by weight, and making the conversions just seems like so much mental masturb@tion.

I haven't read much about the process of mixing by weight, so perhaps mixing by weight is EASIER than mixing by volume, maybe less messy, and maybe its easier to make accurate measurements by weight than by volume. Graduated cylinders CAN be hard to read if the lighting is wrong, they have to be level, and you have to look at it on a horizontal plane, etc. And then you have to clean and dry them. If that's what this is all about, then, fine, we don't have an argument.

I suppose that mixing by weight also has a certain mystique about it, and I wouldn't doubt that this can result in hype.

Comments?

 

[zoiDman]

I Won't say one is Better than the Other. Whatever one feels the Most Comfortable with is the Better.

But for Me, Measuring by Weight has One Big Plus. And that is Less to Wash and Rinse when I'm done.

But I don't do as much DIY as I used to. So it's kinda a 6 or 1/2 Dozen thing for Me.

 

[zoiDman]

...

The only aspect where % by weight would be useful would be in calculating VG/PG ratio. Since the specific gravity of VG and PG are pretty close, the results of a volumetric calculation seem close enough. ...

Actually, the Difference between VG and PG is pretty Significant.

 

[Letitia]

Mixing by weight for me is much more convenient. Now that I premix my base 600ml at a time I only need a syringe for my nic when mixing base. Clean up is minimal.

 

[zoiDman]

If a person Doesn't change their mg/ml or VG to PG Ratios much, Pre-Mix is the Way to Go.

 

[Aerodan]

I'm in experimentation mode, which means the same flavor at different ratios, differing mixtures and flavor or notes. My lazy side wants to have a bunch of milliliter marked GC's, a bunch of milliliter marked syringes and a bunch of rda's. After that weight is easier, but weighing/converting... ml easier no? I'm not in any way a scientist, so can be schooled ​

 

[*RJ*]

I've been mixing liquid for close to a year now and have been mixing by volume, with various graduated cylinders, and recently, syringes for the small measurements.

Full disclosure: I'm a water/wastewater engineer and calculate feed rates, dilutions, volumes, and weights all day long, using metric and English units. I can figure out how many liters/hour of a chemical of a given concentration must be added to treat a stream of millions of gallons/day of water to achieve the required final concentration. Calculations with water based systems are convenient because one liter of water has a mass of one kg. Certain shortcuts can be employed due to this fact. Not so fast with English units.

We buy nicotine liquid that is measured in mg/ml (mass/volume) of solution, not mg/kg (commonly called % by weight) of solution. The final product is also expressed in mg/ml (mass/volume) not mg/kg of solution. As long as the total mg of nicotine is properly measured and calculated, and the total volume of product is properly measured and calculated, the results are perfectly accurate (at least in the spreadsheet).

The only aspect where % by weight would be useful would be in calculating VG/PG ratio. Since the specific gravity of VG and PG are pretty close, the results of a volumetric calculation seem close enough. Who really cares whether the VG/PG ratio is 75/25 or 75.3/24.7? Measuring by weight, and making the conversions just seems like so much mental masturb@tion.

I haven't read much about the process of mixing by weight, so perhaps mixing by weight is EASIER than mixing by volume, maybe less messy, and maybe its easier to make accurate measurements by weight than by volume. Graduated cylinders CAN be hard to read if the lighting is wrong, they have to be level, and you have to look at it on a horizontal plane, etc. And then you have to clean and dry them. If that's what this is all about, then, fine, we don't have an argument.

I suppose that mixing by weight also has a certain mystique about it, and I wouldn't doubt that this can result in hype.

Comments?

My question is do the online ejuice calculators have the densities of pg, vg, nic, and flavors programmed in to make the weight calculations versus volume calculations accurate.

 

[PeterKay]

I've been mixing liquid for close to a year now and have been mixing by volume, with various graduated cylinders, and recently, syringes for the small measurements.

Full disclosure: I'm a water/wastewater engineer and calculate feed rates, dilutions, volumes, and weights all day long, using metric and English units. I can figure out how many liters/hour of a chemical of a given concentration must be added to treat a stream of millions of gallons/day of water to achieve the required final concentration. Calculations with water based systems are convenient because one liter of water has a mass of one kg. Certain shortcuts can be employed due to this fact. Not so fast with English units.

We buy nicotine liquid that is measured in mg/ml (mass/volume) of solution, not mg/kg (commonly called % by weight) of solution. The final product is also expressed in mg/ml (mass/volume) not mg/kg of solution. As long as the total mg of nicotine is properly measured and calculated, and the total volume of product is properly measured and calculated, the results are perfectly accurate (at least in the spreadsheet).

The only aspect where % by weight would be useful would be in calculating VG/PG ratio. Since the specific gravity of VG and PG are pretty close, the results of a volumetric calculation seem close enough. Who really cares whether the VG/PG ratio is 75/25 or 75.3/24.7? Measuring by weight, and making the conversions just seems like so much mental masturb@tion.

I haven't read much about the process of mixing by weight, so perhaps mixing by weight is EASIER than mixing by volume, maybe less messy, and maybe its easier to make accurate measurements by weight than by volume. Graduated cylinders CAN be hard to read if the lighting is wrong, they have to be level, and you have to look at it on a horizontal plane, etc. And then you have to clean and dry them. If that's what this is all about, then, fine, we don't have an argument.

I suppose that mixing by weight also has a certain mystique about it, and I wouldn't doubt that this can result in hype.

Comments?

The main reasons why I personally mix by weight:
1. Everything mixed in 1 bottle- I don't have to clean anything at all after mixing, except for the scale and surface on which i mixed if I spill anything
2. Various free online calculators do all the calculations for me
3. Mixing by weight is slightly more accurate in my case. I often keep VG, PG and distilled water at room temperature, flavorings in the fridge, and nicotine in the freezer. So basically I mix liquids with 3 different temperatures. Since density changes at different temperatures, mixing by weight allows not to worry about it.
I doubt temperature would make much difference and I wouldn't use it as criterion to choose whether to mix by volume or weight but still, it's an additional benefit.
4. I learned how to mix by weight quickly and efficiently so since it works for me, I stick to it.

 

[PeterKay]

My question is do the online ejuice calculators have the densities of pg, vg, nic, and flavors programmed in to make the weight calculations versus volume calculations accurate.

It depends. Some calculators I encountered use same density for PG (including PG based flavorings) and for water (1g/ml), while others use the more accurate 1.04g/ml for PG.

 

[Letitia]

If a person Doesn't change their mg/ml or VG to PG Ratios much, Pre-Mix is the Way to Go.

Frankly I've been at 9mg so long now I just don't notice the minor variances the % of flavors added changes up the strength.

 

[Izan]

I mix 1000ml per batch directly into a 1 liter container. Mixing by weight makes it easy and fast with little to no cleanup.
Nicotine (VG base) and concentrate are both 100ml so 124 grams of nicotine and 101 grams of flavor, the rest is filled with 80%VG premix. Shake and age.

Cheers
I

 

[*RJ*]

It depends. Some calculators I encountered use same density for PG (including PG based flavorings) and for water (1g/ml), while others use the more accurate 1.04g/ml for PG.

Here are some densities of flavors and others from LB. Although they are using the term specific gravity when it’s really density as SG is dimensionless. It would be interesting to see if these slight changes in density of the flavors makes a bit of difference in weight calculations. Probably not in small amounts of flavor. It’s an interesting conversation although I mix by volume. I don’t have the patience to watch a scale fluctuate to the desired point and I can whip up a batch using volume so easily.

Specific Gravity

 

[UncLeJunkLe]

I mix 1000ml per batch directly into a 1 liter container. Mixing by weight makes it easy and fast with little to no cleanup.

Do you mix 1L at once? If so, what scale do you use?

All the scales I've looked at that will measure the weight of 1000ml of eliquid are way more than I would want to spend on a scale. The one's that are under, say, $50, don't go that high.

 

[Izan]

Do you mix 1L at once? If so, what scale do you use?

All the scales I've looked at that will measure the weight of 1000ml of eliquid are way more than I would want to spend on a scale. The one's that are under, say, $50, don't go that high.

I'm using a 20€ kitchen scale; 3000g max, .1g accuracy. I think I bought it at the chino/pound shop/dollarstore.
Mixing into plastic, the weight of the container is less than 75 grams.

Cheers
I

 

[Letitia]

My question is do the online ejuice calculators have the densities of pg, vg, nic, and flavors programmed in to make the weight calculations versus volume calculations accurate.

Most do but but the only one I actually use is elr. They do not usually have flavor specific weights and just use an average.

 

[zoiDman]

Frankly I've been at 9mg so long now I just don't notice the minor variances the % of flavors added changes up the strength.

I'm the Same way. And I vape (about) 9mg/ml also. In fact, I Don't use a Scale or a Graduated Cylinder to make my Pre-Mix.

I just have a Lines Marked on a 250ml Bottle for Diluted VG, another for VG Based 100mg/ml Nicotine Base, and a Top Fill Line for the PG.

I made Pre-Mix in that same 250ml Bottle so many times (in the Same order of Ingredients) that One Day it Dawned on me... "Why don't I just put Lines on the Side of the Bottle and Fill to those?".

Yeah, Maybe one batch will come out to 9.08mg/ml and another will come out to 8.88mg/ml. But Who Cares? I Can't Taste the Difference.

 

[Letitia]

I'm the Same way. And I vape (about) 9mg/ml also. In fact, I Don't use a Scale or a Graduated Cylinder to make me Pre-Mix.

I just have a Lines Marked on a 250ml Bottle for Diluted VG, another for VG Based 100mg/ml Nicotine Base, and a Top Fill Line for the PG.

I made Pre-Mix in that same 250ml Bottle so many times (in the Same order of Ingredients) that One Day it Dawned on me... "Why don't I just put Lines on the Side of the Bottle and Fill to those?".

Yeah, Maybe one batch will come out to 9.08mg/ml and another will come out to 8.88mg/ml. But Who Cares? I Can't Taste the Difference.

I always mix in a glass beaker, just habit reall. On another note I use 250mg so much smaller amount.

 

[vaper1960]

I pre-mix my base by volume (actually doing that today) Just have a plastic bottle (120 ml) with marks every 10 ml (sharpie pen) I make 100 ml batch so have airspace to shake the mix. Very easy to "eyeball" the amounts. When mixing, I use a scale for the flavors then add base (by volume) Never been concerned with accuracy anyway.

 

[zoiDman]

My question is do the online ejuice calculators have the densities of pg, vg, nic, and flavors programmed in to make the weight calculations versus volume calculations accurate.

Just about All the current DIY Calculators I have seen let you use either Volume or Built-In Weight for VG, PG, Nic Base, and Flavors. And most allow you to make Changes to the Weights in a Settings section if you want to.

BTW - Most People I know use 1ml = 1g for PG, PG Based Nic Base, for All Flavorings, and (of course) for H2O.

And most use 1.2x or 1.3g for a ml of VG or Diluted VG or VG Based Nicotine Base.

 

[PeterKay]

I'm the Same way. And I vape (about) 9mg/ml also. In fact, I Don't use a Scale or a Graduated Cylinder to make my Pre-Mix.

I just have a Lines Marked on a 250ml Bottle for Diluted VG, another for VG Based 100mg/ml Nicotine Base, and a Top Fill Line for the PG.

I made Pre-Mix in that same 250ml Bottle so many times (in the Same order of Ingredients) that One Day it Dawned on me... "Why don't I just put Lines on the Side of the Bottle and Fill to those?".

Yeah, Maybe one batch will come out to 9.08mg/ml and another will come out to 8.88mg/ml. But Who Cares? I Can't Taste the Difference.

If your mixes are consistent then yes, I can see how it would make things easier- having marked bottles that you fill up the same way. I can't do it- not only I have different sized smaller bottles (ranging from 30-120ml that I bought in bulk so now I have to use them), I also mix different strengths. My girlfriend vapes 6-7mg so I mix these for her, I vape 3mg, 4-5mg, and 12-16mg, at various vg/pg ratios, depending what device and atty I'm using them with. It would be a nightmare for me to try to mark bottles.