This is part of project I agreed to take on after it was pointed out that so many of the resources in sidebar and wiki are ancient. The idea is, rather than revising them myself, I'd post them here once per week to gather feedback on how to improve them. They belong to all of us, everyone should have a say in what they say.

#Let's talk about Botboy's Guide to Mixing By Weight by /u/Botboy141

I'm not in the mood for sacrilege or blasphemy or heresy or any of that today. Usually I'm totally up for it, but not today. So, I'm not proposing making any changes to the sacred text of The Guide. But like most chapters in holy books, it's quite old. Since it was archived more than three years ago, no one can comment on it now. Let's get some modern-day commentary on Mr. Bot's Epistle to the Subreddit.

Here's the link to the original Botboy141 Guide to Mixing By Weight to preserve the original comments. And here it is reprinted faithfully in its entirety for your convenience and the convenience of generations of mixers to come:

Posting this up here basically to have something to link in the wiki outside of third party how to's.

Whether you're looking to make your blends be more consistent, avoid clean up, avoid cross contamination, mix larger batch sizes, or are just trying to avoid the long term cost of buying syringes and other mixing instruments, well, this is written for you.

##Supplies There are very few supplies that are REQUIRED to mix by weight. They are:

1.) Scale - Scales come in many different varieties and there are tons that would work for most people. There is one major thing you need to AVOID when looking for a scale. You need a scale that DOES NOT have an AUTO-SHUT OFF feature, or at least if it has one, it needs to be on a long delay. A lot of scales by default have a 10 or 15 second auto-shut off, this can mess you up very badly if your scale shuts off while you are trying to add ingredients to a mix. I recommend: American Weigh Scales LB-501 Digital Kitchen Scale for your average DiY'er. Please note that it comes with the calibration weights.

The scale you choose also needs to weigh down to 0.01 grams, additionally, I wouldn't buy a scale that has a limit under 500g.

2.) Pipettes - These are only needed if you have flavoring bottles that do NOT have dropper tops. You can find them on Amazon for ~$20 for a box of 500. This will last the average DiY'er a very very very long time.

3.) Bottles - You will want some dropper bottles for adding PG/VG and Nicotine to your mixes. I'd recommend at least an 8oz bottle, however, if you mix smaller quantities for the most part, you can probably survive with 4oz bottles for PG and VG and a 1 oz for 100mg NIC. I use 4oz for nic and 8oz for PG/VG. You can find these on amazon for under $3 each, or go to a company like www.usplastic.com and get them much cheaper (but have to pay higher shipping).

##Calculator Not too much I need to say here other than give you some basic values. There's only one Calculator that I have used since I started DiY'ing and it works wonderfully for mixing by weight. Calculator Link. The same one (last one) listed in the sidebar. Please note that Google Chrome doesn't like this software download, I assure you it's completely harmless, but Chrome blocks it as malicious.

The basic values that you need to know for mixing by weight are below.

• Weight of PG: 1.038 grams per ml
• Weight of VG: 1.26 grams per ml
• Weight of Pure Nicotine: 1.01 grams per ml

• Weight of 100mg in PG: 1.035 grams per ml
• Weight of 60mg in PG: 1.03632 grams per ml
• Weight of 50mg in PG: 1.0366 grams per ml
• Weight of 48mg in PG: 1.036656 grams per ml
• Weight of 36mg in PG: 1.036992 grams per ml
• Weight of 24mg in PG: 1.037328 grams per ml

• Weight of 100mg in VG: 1.235 grams per ml
• Weight of 60mg in VG: 1.245 grams per ml
• Weight of 50mg in VG: 1.2475 grams per ml
• Weight of 48mg in VG: 1.248 grams per ml
• Weight of 36mg in VG: 1.251 grams per ml
• Weight of 24mg in VG: 1.254 grams per ml

If you have a mix of Nicotine that is not listed above the calculation is fairly simple:

48mg VG based nicotine solution. That's 4.8% pure nicotine and 95.2% pure VG. Pure nicotine weighs 1.01g/ml and Pure VG weights 1.26g/ml. Let's assume we have 100ml for simplicity with decimal points.

4.8 x 1.01 = 4.848 grams. 95.2 x 1.26 = 119.952 grams. If we add these two together: 4.848 + 119.952 = 124.8 grams. Divide it by 100 and we have our weight per ml for 48mg nic. 124.8 / 100 = 1.248 g/ml. This same breakdown can be done for 50/50 blends, just know that the non pure nicotine portion of your base is split 50/50, for example, 60ml in 50/50 mix = 6% pure nic, 94% left over = 47% VG, 47% PG.

When it comes to flavors, there are a couple of thoughts/theories surrounding mixing by weight when dealing with flavors. Many people enter the specific gravity as indicated on an MSDS for every flavor that they have. I feel this is a complete waste of time. After searching hundreds of MSDS sheets for flavors, all flavors fall into a range of .93g per ml to 1.07g per ml.

In order to achieve personal consistency for your juices though, all that is relevant is that you use the SAME value, every time for any given flavor. I simply use a value of 1. This means that whether or not my flavors actually weigh 1 gram per ml, I always pretend they do. Percentages in any given recipe of mine will always be the exact same for me, however, if I am trying to recreate someone elses recipe, or they are mixing mine, there's a chance I'll be off a little bit (no more than 7% which is about the margin of error most people get when mixing by volume).

If you prefer to mix with specific gravity for flavors, you may find /u/sargeant_utestemme's list of TFA specific gravity helpful. /u/tet5uo also acquired some weights from Flavour Art just recently. Also a Capella list compiled by /u/N0CTURN3

##Method The method is pretty subjective but I'll share what I do. It's fairly simple. Any scale you buy should come with a 'tare' button. This resets the scale to zero regardless of the weight on it. This is a button you use quite frequently.

Basically, start off by setting your bottle on the scale, whatever it is you want to mix into. Sometimes for me this is finished bottles, other times when I'm making larger batches, it's 250ml Amber glass bottles.

Now your bottle is on the scale, turn your scale on, this starts your scale @ 0.00g. If you turned it on first and set your bottle on after, no big deal, just press the 'tare' button. Now, The calculator I linked above, gives you the weights you need to add for your Nicotine, VG, PG, and each flavor (once you programmed them in appropriately). I always go in order so I don't miss anything or forget my place (I also have my bottles set up in the same orderly line in my mixing space just to make sure).

For example: I'm making a 15ml batch of my Princess Cake (fruitier version recipe). I'm using 100mg VG nicotine, and am looking for an end result of 40/60 PG/VG.

The calculator gives me these outputs.

I start by adding 0.556 grams of nicotine to my bottle, I round this to 0.56 as your scale likely only reads to the hundredth (at least mine does, thousandth readings on a scale will cost you ~20x the price of the scale). Then press 'tare'.

Next I add my PG (4.476g) rounded to 4.48g. Then press 'tare'. Then VG 10.773 grams rounded to 10.77. Then press 'tare'. Then add your flavors pressing tare after each one. Before you know it, you've mixed your first bottle and have no mess to clean up.

Congratulations, you just mixed your first batch of juice by weight.

Any questions, shoot away.

Edit: Edited the math on calculating weight of nicotine in PG/VG to make it (hopefully) simpler to understand. My wording was a bit funky!

Edit: Added some more notes about the calculator, also added the link to /u/tet5uo's post about FA specific gravity.

Edit: Added a simple comment noting that YOU need to input specific gravities for PG/VG/Nic into the calculator.