Sciencemadness Discussion Board

Accuracy and calibration of cheap eBay balances

Brain&Force - 22-7-2015 at 22:54

So I got some cash for my birthday and I'd like to invest in a few interesting chemicals - but first I need to get a balance! I've been eyeing my chemicals for way, way too long.

I'm considering getting a cheap eBay balance to do some interesting chemistry with lanthanide malates and ascorbates (as well as some stearates if available - I want terbium fluorescent soaps to be a thing :D) However, I'm going to be working with pretty small amounts (<1 gram) and I want to be able to get accurate masses, especially with small amounts of material. I'd like to find a balance that goes up to 100 grams to milligram accuracy but the get pretty expensive. I found this 10 gram/milligram balance, but I'm not sure if that maximum mass will be too low. Are these balances accurate enough for general use in the amateur lab, and are there generally ways to calibrate them, even if they say they "self-calibrate?"

Sulaiman - 23-7-2015 at 02:23

there is a topic on this somewhere here,

summary ....
. the last digit is usually within 2 digits accuracy, commonly +/- 1 digit.
e.g. 10g x 0.001g scale may be in error by up to 0.002g,
which is more than good enough for amateur chemistry.
You DO need a calibration weight as factory shipped calibration is unreliable.

careysub - 23-7-2015 at 05:22

This one:
http://www.sciencemadness.org/talk/viewthread.php?tid=38823

The Gemini 20 balance is a 20x0.001 g balance available for $25 on Amazon. I have one and it is accurate too about 1 mg using some small test weights I have (the balance ships with a test weight as well).

[Edited on 23-7-2015 by careysub]