NOTICE about DIY Thread:" Mixing juices by weight Percent" - DO NOT FOLLOW AUTHORS METHOD AS IT IS POTENTIALLY DANGEROUS

[Smoogle]

Hello All,

I felt compelled to make this my first post because I found a thread on this forum that is grossly inaccurate and could result in a dangerous situation for some DIYers. I was unable to post on the thread due to my newb status.

The thread "Mixing juices by weight Percent" under DIY e-liquid is an attempt to educate on mixing e-liquid using a scale versus the more common method of volume (using syringe or counting drops). The weight percent method predominantly applies to large batch mixing and is the most common, accurate, and repeatable method if mixing for commercial purposes.

The author’s mistake in calculations started at his conversion from a gallon to milliliters - he incorrectly stated 1 gallon as 7570.824ml, when in fact it is half of that at 3785ml. This mistake led to a chain reaction, causing remaining calculations to be incorrect and potentially dangerous to those unaware. I don't wish to offend the author, but for someone who claims that he's made "literally millions of gallons of exotic industrial chemicals" and has "a US patent "Method for Continuously Blending Dilute Chemicals"", not to mention he's an Ultra-Verified-Supporting-ECF-Veteran Member, his post is incredibly erroneous and irresponsible. Mistakes are made all the time, but when writing about mixing e-liquid, which usually contains nicotine, these mistakes may be more costly.

In addition, I do not understand how the author was capable of continuing his calculations without noticing his mistake. Basic math tells us that if a liquid has a specific gravity over the value "1", then 1 ml of that liquid will weigh more than 1 gram. The following incorrect calculations made by the author:

Grams per ml conversion:
1ml Flavoring = .5g
1ml 100% PG = .63g
1ml 100% VG = .52g
1ml 50/50 PG/VG = .54g

Should read (calculated using author's stated Specific Gravity [SG])

Grams per ml conversion:
1ml Flavoring = 1g (1ml x 1 SG of Flavoring)
1ml 100% PG = 1.036g (1ml x 1.036 SG of PG)
1ml 100% VG = 1.249g (1ml x 1.249 SG of VG)
1ml 50/50 PG/VG = 1.1425g (1ml x 1.1425 SG of PG/VG)

For those interested in learning without complicated, erroneous babble; the weight (measured in grams in this case) of a liquid will be its volume (measured in milliliters in this case) multiplied by its specific gravity (or its density with respect to water). Water has a specific gravity of 1, so 1ml weighs 1 gram. If VG has a listed specific gravity of 1.249, then 2ml of VG will weigh 2.498 grams.
The author not only made a mistake by factor 2, he also confused the Specific Gravity of PG and VG in his above Grams per ml conversion.

Sorry if I offended anyone, but felt a responsibility to correct this.

Thanks,
Adam

 

[amanda211]

I use the ejuice calculator. There are way too many numbers and calculations in that for me. I've always stunk at math.

 

[Ryedan]

Hi Adam and welcome to ECF.

I think you're right and there are mistakes in those calculations. Thanks for pointing this out. The error was pointed out further down in that thread too

Yes mistakes can be costly. IMO 'incredibly erroneous' is a stretch, for what is basically one math error. Those who do things sometimes make mistakes and those mistakes always seem silly after the fact to both that person and to others.

'Incredibly irresponsible' in this case is IMO more than a bit ridiculous. The poster is a respected member of this community who has contributed much and helped many. One honest mistake does not make a reputable person irresponsible.

Vape on

 

[AttyPops]

I'd rather see the OP of that thread fix the math and have a mod edit the 1st post to avoid improper calculations for people using that method in the future.

Blame/names are irrelevant. But accurate info counts. Mistakes happen, so we fix and perfect going forward.

The OP put a lot of work into that post so he deserves credit and a chance to fix it up.

Also for the 1st post in this thread:

....
Grams per ml conversion:
1ml Flavoring = 1g (1ml x 1 SG of Flavoring)
1ml 100% PG = 1.036g (1ml x 1.036 SG of PG)
1ml 100% VG = 1.249g (1ml x 1.249 SG of VG)
1ml 50/50 PG/VG = 1.1425g (1ml x 1.1425 SG of PG/VG)
.....

Thanks,
Adam

IDK...most flavoring is in a PG base. Some is VG based. So IDK how any flavoring could have a SG of 1. ??????????????

Anyway, that's the challenge of using the wight method...you have to know all the ingredients (or measure their specific gravity every time you get a new batch) and have reproducible results. Fortunately for things like flavoring, it doesn't matter as much. Nic base concentration, OTOH, should be exact, or at least very close.

 

[Smoogle]

Ryedan:

Thank you for the warm welcome and feedback. I re-read my post and agree that it comes off a bit harsh, my apologies for the unnecessary chatter. I don't doubt the poster's respected position in this community. I was driven to say "his post is incredibly erroneous and irresponsible" because one member repeatedly sought an answer to why 1ml of liquid isn't around 1g. Neither the poster nor anyone else pointed out that there was an error – my strong, and perhaps “more than a bit ridiculous” response was influenced by the [perhaps wrong] assumption that there were overlooked opportunities to correct the mistake. I was mainly unnerved when the poster indirectly stated that 1ml of water weighs 0.5g, and that VG and PG are about half the weight (density) of water, without realizing. These are obvious mistakes (by factor of 2) that are difficult to overlook (I stand firm on that). I didn’t mean to offend anyone, just thought it was a pretty big deal; unfortunately some of my annoyance shined through.

AttyPops:

You are correct, Flavoring may not necessarily have a Specific Gravity of 1. All SG values in my post are consistent with the OP’s from the thread in question. I used the same values to be consistent with my corrections. SG of Flavoring will vary depending on the flavor and its carrier(s), and may even be less than 1 if alcohol is used as a carrier for example. I use a scale to mix e-liquid and assign a SG of 1 to each one of my flavors because it’s easy and assures consistency from batch to batch. Following this logic, the Specific Gravity of flavors is completely irrelevant when using the weight method, it's no different than using the volume method. To make a good juice, and to make it good consistently, we depend on ourselves to have just the right amount of each flavor and we depend on the flavor manufacturer to be consistent from batch to batch. If a flavor comes weaker or stronger than usual, we compensate with amount. We can make juice and consistently recreate juice using only weight or only volume. For me, knowing the right amounts by weight has big advantages for small and large scale mixing. This might be a stretch, but it’s quite possible that specific gravity is completely irrelevant whatever the scenario is. Maybe the only time SG values are necessary is when you're required to make exactly x amount of liquid in ml, and all you have is a scale for measuring….

For anyone interested in using the weight/scale method to mix e-liquid, they might find the following info and personal opinions helpful.

When talking about mixing e-liquid and liquids in general, Specific Gravity and Density are used interchangeably. Density is mass per volume, and Specific Gravity is simply the density of a substance divided by the density of water (density of water is always used as a reference for liquids, air, and gases). Since water has a density of 1 gram/cm3 (at std. temp. and pressure) and all units cancel themselves out when divided, SG is usually close if not exactly the same value as density, but without the units obviously. Manufacturers of USP compounds will sometimes list one or the other, or both. The commonly accepted values for Specific Gravity of USP Glycerin and USP Propylene Glycol:

• Specific Gravity of USP Glycerin is 1.26
  
  
• Specific Gravity of USP Propylene Glycol is 1.038

Food flavoring that I use is most commonly carried in PG, which has a SG of 1.038. If we assume that the natural and/or artificial flavors and molecules used to make a single flavor can "thin" out the PG, the liquid will become less dense and will therefore have a lower SG. If alcohol is added, density will drop even further. It is entirely possible that a single food flavor can have a SG of 1. I think it's also possible for flavor molecules to add density and raise the SG. Some flavor manufacturers have a data sheet for each flavor, listing density or SG. I’ve found that food flavoring from professional and reputable companies is very consistent, otherwise the flavors would be off and companies wouldn’t remain reputable. I use an SG value of 1 for each flavor, all the time. This is perfectly acceptable as long as I always use an SG of 1 for each flavor, in each recipe and each batch.

If desired, the density or SG of a liquid can be found using a graduated cylinder and scale. This is a relatively simple procedure, instructions can be found on the internet. Ultimately, it is more important to be consistent than to know the exact specs of each ingredient. USP Glycerin and USP PG is easy, I've only seen consistently tight specs (I think this stuff comes from one or two manufacturers) or the differences are too slight to matter at any quantity. I think that because a lot of industries depend on these two products to be consistent and they're made in such huge quantities, not to mention they're pretty simple compounds, any meaningful variations are rare; I could of course be wrong, this is just an observation from the limited experience I have. As far as density of Nicotine solution goes, it’s more important for me to confirm the concentration of nicotine, since the carrier will most likely be consistent in density from batch to batch. If you're selling e-liquid, I think it's a good idea to ask your vendor if the nicotine solution comes from the same overseas vendor each time and consider requesting a data sheet for each batch you get – not sure many vendors can offer this, but I'd stick with ones that can. You can always check density yourself using the mass/volume formula. This really isn’t that important unless you’re making 100’s of Liters at a time. I also suggest to check Nicotine concentration using a Kit and always get your Nic from the same reputable vendor who preferably receives it directly from overseas (I like to think that I’m avoiding Nic suppliers that purchase in bulk from other US suppliers and simply repackage).

The weight method is preferred for larger scale mixing mainly because it’s quick, easy, more aseptic, and there’s less chance for error. I prefer it for small DIY mixing as well, down to 5ml. No syringes are used, all my flavors and additives are bottled with glass droppers so it’s easy to add the correct amount in grams; Nic, Glycerin, PG is kept in large Boston Round glass bottles with glass droppers or large HDPE bottles with dropper inserts. All you need is a scale with 0.01g readability at minimum. I never use syringes.

If your perfected recipes have all the ingredient amounts listed in grams, you can quickly, easily, and accurately recreate the recipe each time.

A quick example using typical e-liq calculator and scale:

10ml of 60PG/40VG (approximately), 1.8% Nic

• 10% (100mg/ml) Nicotine in PG – 18% or 1.8ml
  
  
• RY4 Double – 8% or 0.8ml
  
  
• 555 Tobacco – 5% or 0.5ml
  
  
• Vanilla – 4% or 0.4ml
  
  
• Caramel – 3% or 0.3ml
  
  
• PG – 22% or 2.2ml
  
  
• Glycerin – 40% or 4.0ml

If I assume (or confirm) that my Nicotine in PG has Specific Gravity of 1.035, I multiply 1.8ml by 1.035, which equals 1.863 grams that is added to empty bottle on tared scale. Scale is tared after each time an ingredient is added.

I use a Specific Gravity of 1 for each of my food flavorings when I create e-liquid, it’s easy and assures consistency from batch to batch (a liquid with SG 1 simply means 1ml=1g). So I add the 0.8g of RY4 Double, followed by 0.5g of 555, then 0.4g of Vanilla, and finally 0.3g of Caramel, taring the scale between each ingredient to make math easy and reduce chance for mistakes.

For PG, I add 2.28g, which is 2.2ml x 1.038 (1.038 is Specific Gravity of PG)

For Glycerin, I add 5.04g, which is 4ml x 1.26 (1.26 is Specific Gravity of Glycerin)

Hope this helps someone. Rock n roll.