Sciencemadness Discussion Board

Scales

einstein(not) - 30-6-2009 at 14:14

I'm thru with cheap ass scales! I need opinions for the best scale for use in a hobbiest lab that has at least 1000 gram capacity and a large platform. Preferably digital.

Here are some I'm looking at.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName...

As you can see I'm also looking at beam scales. Which ones are more accurate? Which aare more durable?

[Edited on 30-6-2009 by einstein(not)]

crazyboy - 30-6-2009 at 14:26

What kind of work are you doing? Unless you are doing industrial size reactions all of those scales are useless they are all incredibly inaccurate for lab use. I have two scales one with max of 500g accurate to .1g the other 150g max accurate to .01g.


They are both digital, accurate and cost less than $10.

einstein(not) - 30-6-2009 at 14:47

I have a small 500 gram digital pocket scale. My problem is the size of the platform makes it very difficult to use. For instance I was making nitric acid a few weeks ago and measuring out 1500 grams of calcium nitrate was a pain in the ass. It spilled and got under the platform and was hell to get out.

Rich_Insane - 30-6-2009 at 18:34
Quote:

What kind of work are you doing? Unless you are doing industrial size reactions all of those scales are useless they are all incredibly inaccurate for lab use. I have two scales one with max of 500g accurate to .1g the other 150g max accurate to .01g. They are both digital, accurate and cost less than $10.


Where did you obtain the scale? It has been hell for me looking for a good scale 150 g to 0.01 g under $50.

crazyboy - 30-6-2009 at 19:23

Quote: Originally posted by Rich_Insane  


Where did you obtain the scale? It has been hell for me looking for a good scale 150 g to 0.01 g under $50.


It isn't exactly top of the line but it gets the job done:

http://cgi.ebay.com/NEW-0-01-200g-GRAM-MINI-POCKET-DIGITAL-B...

woelen - 30-6-2009 at 22:49

For more serious work I would recommend a scale which has a resolution of 0.001 gram or better. Such a scale allows one to do microchemistry experiments while still maintaining good accuracy (provided you take good care to avoid mechanical losses).

I have one scale with a range of 100 grams and a resolution of 0.0001 gram and another scale with a range of 300 grams and a resolution of 5 grams. The latter is good for bulk work, but for fine work it is totally useless.

1281371269 - 1-7-2009 at 02:27

I just bought this rather wonderful item:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageNa...
after my cheap as hell digital scales suffered an acid attack (although actually what killed them was using water to try to get it off).
It says it will weigh .1g to 25g, which will mean I might need another scale for larger amounts, but they should last a lot longer than cheap digital ones and be more accurate.

Proper laboratory balances start at around £200 and go into the thousands but I'm sure it's a 'you get what you pay for' situation.

Edit: Just got a refund for those scales - Weights weren't included and would have to have be shipped from America.

[Edited on 1-7-2009 by Mossydie]

ammonium isocyanate - 18-7-2009 at 14:34

Home Science Tools sells 200g pocket scales w/ .01g resolution for $39.95. I have one and it works well as long as you're out of the wind, but it needs to be calibrated fairly often. Luckily, a 200g calibration weight comes with it.

ScienceSquirrel - 19-7-2009 at 16:54

I use a set of scales that do 0 - 100g in 0.1g increments that cost about £25 for my preparative experiments.
I have tested their linearity using piles of 2p pieces and they are OK.
The error is tiny compared with say the variations due to slightly changed experimental conditions.
For the small scale preparation of alums, Rochelle salt, metal complexes etc they are OK.
Most home chemists are at best using technical reagents so the accuracy of the scales is one of the lesser factors in the equation.