Inaccurate Syringes - Buyer Beware

[Exchaner]

I just learned a lesson it doesn't always pay to go for the lowest price. A bunch of syringes I ordered from Amazon turned out to be mis-caliberated. A careful measurement showed the actual capacity is 3.1 ml instead of 3 ml as represented. I repeated these measurements using three different methods with identical results. If you were trying to prepare 30 ml of 24 mg nicotine for example you would end up with 24.8 mg instead. That by itself may not be significant, but when measuring highly concentrated flavorings, you could end up way off the mark. Here is a link to the item which by BTW I wasn't aware was being shipped from China.

Amazon.com: 10pcs 3ml 3.0cc Luer-Lock PP Syringe Accurate Measuring Brand New: Health & Personal Care

 

[dkettle]

Is that 3.1 ml including the blunt tip? Some blunt tips can hold up to 0.2 ml.

 

[Exchaner]

3.1 ml is the amount inside the syringe; I made sure to exclude contents of the tip.

 

[Alien Traveler]

Not a problem for me.

 

[dkettle]

In "most" appliances an error of +-5% is acceptable. That 0.1 is still within that 5% error margin. Now that 5% would be unacceptable say if we were injecting insulin to a 5 lbs newborn but for our purposes of mixing it is acceptable. Mind you that "extra" accurate syringe for the newborn costs $50 a pop while ours cost 50 c or less

 

[Mr.Mann]

In "most" appliances an error of +-5% is acceptable. That 0.1 is still within that 5% error margin. Now that 5% would be unacceptable say if we were injecting insulin to a 5 lbs newborn but for our purposes of mixing it is acceptable. Mind you that "extra" accurate syringe for the newborn costs $50 a pop while ours cost 50 c or less

Yeah, I got a relatively accurate graduated cylinder (cheap, but decent -- about +/-.2) and if that is correct, even with that +/- .2 ALL my syringes lie like Jayson Blair! (I check them all out in various faux mixes with my syringes). I't's pretty nerve racking to not really know the truth about percentages, but I do realize repeat-ability is the most important thing. It really becomes problematic if you are adding a lot of different flavors into one mix as that just keeps on adding more and more "extra." I have not found a decent solution specifically to address the ever-growing off-ness in volume measurements, but for now I am just tweaking here and tweaking there (and using pre-dilutions quite effectively).

I have thought about weighing instead, but I am thinking that could get really number-maddening for me. I am open to suggestions, but mostly it's all in fun anyway and a good mix doesn't really care if the numbers are "true", as long as they can be repeated.

For nic that could be an issue, but not too biggie when you can just dilute a touch more to satisfy fears.

Like dkettle said though, man, quality and super accurate chemist tools are really expensive, so much so that it is just cost prohibitive. I still want some non-wetting graduated cylinders though -- they're not too pricey, but accuracy will drop with price.

 

[cbabbman]

A scale and a set of calibration weights. The amount of headaches it eliminates is incredible.

 

[Mr.Mann]

A scale and a set of calibration weights. The amount of headaches it eliminates is incredible.

Can you provide me with a link to what you use?

 

[Soignee]

A scale and a set of calibration weights. The amount of headaches it eliminates is incredible.

Additionally, HotRod's calculator can be set up for measuring by weight.


Sent from Stoooopidtalk!

 

[cbabbman]

Can you provide me with a link to what you use?

I tried a few inexpensive scales from Amazon and they were fine except they wouldn't handle more than a small bottle.. I ended up going with this one and it was worth every single penny.

http://www.tmart.com/300g-x-0.001g-B3003T-Electronic-Balance-Laboratory-Scale-White_p152567.html

I choose to use a .001g resolution as it actually let's me see every drop I add. A .01g scale will work fine but I prefer to see everything as I add... AND, this scale doesn't auto shut off on me when plugged in.

and ditto on hotrod's calculator... best one out there IMHO

 

[Mr.Mann]

I tried a few inexpensive scales from Amazon and they were fine except they wouldn't handle more than a small bottle.. I ended up going with this one and it was worth every single penny.

http://www.tmart.com/300g-x-0.001g-B3003T-Electronic-Balance-Laboratory-Scale-White_p152567.html

I choose to use a .001g resolution as it actually let's me see every drop I add. A .01g scale will work fine but I prefer to see everything as I add... AND, this scale doesn't auto shut off on me when plugged in.

and ditto on hotrod's calculator... best one out there IMHO

Thanks man. Hopefully soon I will be able to get into the groove (which you should understand, assuming that's you in the avi with the ax! LOL)

 

[cbabbman]

Thanks man. Hopefully soon I will be able to get into the groove (which you should understand, assuming that's you in the avi with the ax! LOL)

I groove about 100 gigs a year. Lol.

Good luck... you truly won't regret weighing. It makes it about a thousand times easier and more enjoyable.

 

[amoret]

I use http://smile.amazon.com/gp/product/B00AN44MJI/ref=oh_aui_search_detailpage?ie=UTF8&psc=1, and 500 g is plenty for what I make.

And another vote for Hotrod's calculator.

 

[Exchaner]

If I wanted to mix by weight, doesn't that throw the calculations off if a recipe is based on volume and not on weight? 1ml of pg does not weigh the same as 1 ml of vg, or alcohol or distilled water.

 

[Boletus]

If I wanted to mix by weight, doesn't that throw the calculations off if a recipe is based on volume and not on weight? 1ml of pg does not weigh the same as 1 ml of vg, or alcohol or distilled water.

I believe the calculator applications compensate for that, based on standard densities for the ingredients. If you do your own calcs, then you will want to find those densities (or equivalently, Specific Gravities) and incorporate them into your spreadsheets.

However, I also like to say that the "=" sign only really exists between the covers of mathematics textbooks, everything else is an approximation. For example, no one can say that every bottle of VG you might get has a density of exactly #.## mg/ml. But also, as pointed out in this thread, syringes have some inherent inaccuracy too.

 

[Soignee]

If I wanted to mix by weight, doesn't that throw the calculations off if a recipe is based on volume and not on weight? 1ml of pg does not weigh the same as 1 ml of vg, or alcohol or distilled water.

HotRod's calculator allows the input of specific weights of pg, vg etc...I believe one of the latest versions may have it set up already...

 

[HotRod19579]

If I wanted to mix by weight, doesn't that throw the calculations off if a recipe is based on volume and not on weight? 1ml of pg does not weigh the same as 1 ml of vg, or alcohol or distilled water.

The calculator calculates all of the percentages based on volume and then calculates the weight of each ingredient to add by multiplying the grams/ml by the number of ml's called for in the recipe. No changes or conversion of recipes is required.

 

[cbabbman]

The key is hotrod calculator to start with. There are a few other threads that discuss the weight per ml that you plug into the program.

 

[misu]

I just learned a lesson it doesn't always pay to go for the lowest price. A bunch of syringes I ordered from Amazon turned out to be mis-caliberated. A careful measurement showed the actual capacity is 3.1 ml instead of 3 ml as represented. I repeated these measurements using three different methods with identical results. If you were trying to prepare 30 ml of 24 mg nicotine for example you would end up with 24.8 mg instead. That by itself may not be significant, but when measuring highly concentrated flavorings, you could end up way off the mark. Here is a link to the item which by BTW I wasn't aware was being shipped from China.

Amazon.com: 10pcs 3ml 3.0cc Luer-Lock PP Syringe Accurate Measuring Brand New: Health & Personal Care

Here's the thing. If you're getting something on Amazon, it's probably a seconds lot. Meaning that they weren't good enough for medical use. I love Amazon, but there are certain things that I just won't buy from them. I would still buy syringes from them until I got brave enough to dose my own nicotine.
As others have mentioned, the needle does hold fluid as well. And if you want to get really technical about it - a 14g will hold more than an 18g because the 14g is a bigger bore. When I worked in dialysis, we used 15g and 16g. Once, I used a 14g and it was like a garden hose.
From a medical standpoint - 18g is the lowest gauge used for blood transfusions. Blood is pretty thick. I'm still a newbie at vaping. The B&M juice I have is fairly thin. I haven't bought pure VG yet so I don't know how the two viscosities compare. If VG is thicker than blood, I'd lower the gauge.
If you're drawing up nicotine, I would use a dedicated syringe for that. If you want exact precision, go to your pharmacist and buy a set up so you can specifically dedicate it to dosing nicotine.
Excellent thread!! It's given me even more to consider when making my own juice. This is a good thing because I want my juice to be good!

 

[1vapeatatime]

I've used drops for measurement and steered clear of syringes, ever since I started mixing. I understand different flavors come in various densities, therefore yielding different size drops.
That being said, any one flavor is going to yield the same sized drop every time if I use the same sized dropper. so when measuring a batch it looks something like this: Flavor X 09dr/05mls, and so on.
I'm making juices for myself and a couple of friends, and it has worked so far.
I realize that I'm probably not being the most scientific, but I found no reason to change....yet.
I do use graduated cylinders and beakers for my base liquids and nicotine, as well as my 30ml and 50ml batches.