Precision in DIY

[donnah]

When you are mixing, how precise are you?
Do you measure everything with 1/10 ml precision or just count drops? Or something else?

I am very precise when I mix my base.. 12mg 70%pg 30%vg. But not so much when I add in flavoring. I just count out some drops. I use very very light flavoring and it's pretty much maybe 2 or 3% of my mix. For instance, when mixing caramel cappuccino.. I use one drop per 10ml and one drop sweetener per 10ml.

 

[The White Rabbit]

What concerns me about accuracy is when I don't end up with the amount that I am trying to mix. Like I've got the amounts of everything for my 15ml bottle. Add them all and end up with 14.5ml. It's the VG that gets stuck to the sides of the droppers I use, I'm trying to be more patient and letting it all drip down, but even then I still lose some. I've still changed my system to reflect that though, if I'm making 15ml, I use the ingredients for 16ml.

Experts might be able to advise with this though; how do I account for the liquids in the syringe when I am mixing? When I syringe up 1ml of fluid, aren't I always getting like 1.1 or 1.2ml total, including what's in the needle?

 

[MISTer E]

One trick I discovered, is to use an ejuice calculator to assist in the accuracy of determining my end unit size. For example: If I want to make a batch of around 60ml 24% 50VG/50PG unflavored vapejuice from some 100%nic.

If I adjust the end unit size/"amount to make" up 10ml & down 10ml one @ a time (61,62,63,so on) I find that going down to 50ml gives a number that is easier to hit the "bullseye" on.

Somewhat of a rearrangement of selecting the measuring device size depending on the amount to be made. Example: dropper to measure 1/20ml instead of a 1000ml graduated cylinder

NOTE: Do not use that recipe unless you use 50/50 100% nic base

 

[Swampey65]

Yes! I think Breaktru's calc is hands down the best! It's the only one I use now.

It's nice to be able to save recipes that turn out perfect, and be able to go back to them again & again!

 

[Iffy]

If I adjust the end unit size/"amount to make" up 10ml & down 10ml one @ a time (61,62,63,so on) I find that going down to 50ml gives a number that is easier to hit the "bullseye" on.

Yepper, I've done that 'dance' also.

 

[The White Rabbit]

If I adjust the end unit size/"amount to make" up 10ml & down 10ml one @ a time (61,62,63,so on) I find that going down to 50ml gives a number that is easier to hit the "bullseye" on.

I do this regularly with my smaller test batches. I'd prefer to make a 3ml batch, but I find myself going to 4,5, or 6ml to get rid of decimal places. I'd not really considered doing it the opposite way. I'll give that a shot.

 

[cricque]

Thats also a way of doing it, making bigger batches. But that's good once you have hit the thing you want. If you are still testing out some thing, you won't make 100ml of juice .

But honestly if my premix juice is 23%VG/77%VG. I don't mind, but my premix generally is 11mg 50/50 these days, so thats easy pretty easy to make . But I really aint going to fiddle with 0.1 more VG/PG or so, since this really won't affect much

 

[nanovapr]

Ratsey, I am not an expert with chem or precision measuring by any means. I think that unless you are mixing micro-batches of 1ml or less, the volume contained in a syringe needle (of the gauges we would be using) is not even measurable on the scale of "I or anyone else can detect the difference".

Pouring VG is probably the most inaccurate thing we do, because of it's thickness. Warming it will help. For batches of 30 ml or so, a 5ml syringe with the needle removed is a handy and accurate way to measure and dispense VG. It fits into the mouth of the bottle I store VG in, and without a needle, can slurp up a syringe-full in two seconds. Because a syringe (a positive displacement device) definitely empties it out, you don't have a thick layer of VG hanging onto the walls of a graduated cylinder, and is more accurate. For larger batches, I use a graduated cylinder for VG, and just let it drip for a long time (burrette clamp/stand to hold it, so I can do something else).

Pipette pumps and pipetting syringes can be even more accurate for small amounts.

I mix for other people, so I try to take more care in measuring than if it was just for myself.

 

[zoiDman]

Here is something I posted about the Volume inside a 18ga Needle.

The amount for the Drop Size is incorrect. It should be about .3571 Drops if 20 Drops per ml is being used.

Just a little quick Math.

The Nominal Inside Diameter (ID) of an 18 ga Hypodermic Needle is .033"

If the Hypodermic Needle is 1" Long, the Volume inside the Needle in Cubic Inches is V = (π(.033/2)^2) x 1 => V =.0009 Cubic Inches.

If 1 Cubic Inch is Approximately Equal to 16.3871ml => .0009 Cubic Inch = .0140ml

So a 1 Inch Long 18 ga Hypodermic Needle contains .0140ml of Volume.

To put how Small this Volume is in Perspective, .0140ml Error with respect to 10ml is .14%. Or if there are 20 Drops in 1ml, than .0140ml is Equivalent to .0007 Drops.

My Suggestion is if you are Really Concerned with making a Measurements at the .0140ml Level that you might Check the Accuracy of your Syringes and or Graduated Cylinders. Because .0140ml probably Exceeds the Level of Accuracy of your Syringes or Graduated Cylinder by a Factor of 7.

You also may want to consider at what Temperature and Atmospheric Pressure you are Measuring your Liquids. .0140ml may approach the Relative Difference of Volume do to Thermal Expansion when there is a 15 Degree Fahrenheit Change in Temperature.

A Fundamental Rule of Measurement is that if the Amount being measured is Less than the Accuracy of the Measuring Equipment, that Accuracy Cannot Be Guaranteed. Precision perhaps but Not Accuracy.

 

[The White Rabbit]

burrette clamp/stand

Capital idea good sir! And I won't worry about the liquid in the needle any more, it really is a minute amount, I don't need to be THAT accurate.

 

[gentlemancole]

Pipette pumps and pipetting syringes can be even more accurate for small amounts.

I was thinking about picking up a pump and a few pipettes today. It's definitely happening now.

 

[cricque]

I mix for other people, so I try to take more care in measuring than if it was just for myself.

I agree, If i make something for other people I always check that PG/VG ratio and mg is correct (up to a certain point). Then I add my drops from my glass bottles with all the same droppers. Just works out perfectly that way. The juice has the same taste all the time.

But once more the 0.1% more VG or 0.1% more PG isn't going to affect the overall taste/throathit. And when I mix for other people it generally is 30ml or so. With larger numbers it just gets easier

Also recently I just bought 12mg 50PG/50VG and that should work out fine for me, since I only need to add my flavoring. SO i'll get around 11mg somewhere. And from that vendor if you buy 36mg and add PG/VG yourself you perhaps save like 25 eurocents or so. Yes, its money, but on 300ml 25 eurocents reall is not that much. So lets see how it goes with the premixed