Measuring Inaccuracies for DIY

[VaporSmith]

I had been using a generic 6ml syringe for all my DIY measuring and picked up another at Walgreens awhile ago as I started down the DIY road. Since I do a lot of 2ml test samples accuracy is very important to me. I spent months logging in and testing all my sample receipes using the 6ml syringes as the measuring tools. Then I got a 12ml syringe that looks more "medical grade" from a vendor to make my 10ml batches and noticed using the 12ml syringe that my 2ml test batches almost filled a 3ml bottle? At first, I figured the viscosity of the VG (10-20%) added volume but that wasn't the case upon further testing.

Testing using plain water, 1 ml from either of the 6ml syringes equaled about .8 ml in the 12ml syringe making all my reciepes inaccurate ! I understand it's all relative but I was wondering if anyone else noticed this problem and how you handled it?

 

[Switched]

The only problem I can see with this set up is if you use different syringes for the same mix. If you use the same one for all ingredients, the error is uniform and the difference negligible, if any.

 

[Rocketman]

Often the "first mark" is the source of error in measuring devices. Delta measurements from one mark to another will still have linear scale error. With a 6ml syringe from 4 to 2 or 5 to 3 would be the desirable 2ml volume. One or two ml from a 12ml syringe may also give resolution error if graduations have less resolution.
Use the meniscus and measure from mark to mark, don't "empty" the syringe as part of the measurement.

Rocky

 

[7thCabal]

I had been using a generic 6ml syringe for all my DIY measuring and picked up another at Walgreens awhile ago as I started down the DIY road. Since I do a lot of 2ml test samples accuracy is very important to me. I spent months logging in and testing all my sample receipes using the 6ml syringes as the measuring tools. Then I got a 12ml syringe that looks more "medical grade" from a vendor to make my 10ml batches and noticed using the 12ml syringe that my 2ml test batches almost filled a 3ml bottle? At first, I figured the viscosity of the VG (10-20%) added volume but that wasn't the case upon further testing.

Testing using plain water, 1 ml from either of the 6ml syringes equaled about .8 ml in the 12ml syringe making all my reciepes inaccurate ! I understand it's all relative but I was wondering if anyone else noticed this problem and how you handled it?

Good observation-- when dealing with liquids you will never get all of what you put into a vessel out of it, even h2o.

But as long as you mix in one vessel your ratios should be okay-- its just when you transfer the liquid it would be impossible to get the original finished mix volume into a different container-- if you find out how to do that, then let everyone else know.

DIY is not a destination... its a journey. Enjoy!

 

[Kate51]

There's no problem with variable measurements, as long as you use the same ratio or formula, and as long as you use the same instrument throughout your 'mix'. ..an awful lot of people use "drops", which are far less accurate between viscosities of different liquids and droppers, but again if you replicate it the same way everytime it will still work.
Yes, it is all relative.

 

[Nikhil]

The only problem I can see with this set up is if you use different syringes for the same mix. If you use the same one for all ingredients, the error is uniform and the difference negligible, if any.

Actually this can be a huge problem when working with small amounts, even if the syringe is the same. If the syringe is adding 0.1ml each time, then when you have a recipe using 0.2ml, 0.2ml, and 1.6ml, you actually end up with 0.3ml + 0.3ml +1.7ml, which has very different end %'s. As his 2ml batches were nearly making 3ml, the difference is even more than that.

Rocketman's suggestion was good.

 

[VaporSmith]

Thanks for the help and insight !