Author Topic: You want a digital scale for What?? (Read 8288 times)

GlennSprigg · « **on:** July 30, 2020, 12:27:33 pm »

Ha!! I found this accidentally, on eBay...
https://www.ebay.com.au/itm/1-x-Portable-100g-0-01g-Mini-Digital-Scale-Jewelry-Pocket-Balance-Weight-LCD-AU/333550988799?_trkparms=aid%3D333200%26algo%3DCOMP.MBE%26ao%3D1%26asc%3D20180801154222%26meid%3Df9e817e14bdc4af3a5f9688fa7b94b3b%26pid%3D100044%26rk%3D1%26rkt%3D5%26sd%3D161698485906%26itm%3D333550988799%26pmt%3D0%26noa%3D1%26pg%3D2508447%26algv%3DItemStripV5%26brand%3DUnbranded&_trksid=p2508447.c100044.m43681

Digital Electronic scales, for only $8.50 !! I can't IMAGINE what prospective purchasers would
want it for, (?). Would be neat for all the 'above-board' uses they recommend, I suppose.

The pictures confused me for a while, until I realized that the whole thing is the size of a typical
car Remote, and the outer cover makes it 'look' like that's what it is!! I guess there's a market...

P.S.
I do not condone drug usage. Never have, and never will, except from my Doctor!

mrflibble · « **Reply #1 on:** July 30, 2020, 12:51:34 pm »

Quote from: GlennSprigg on July 30, 2020, 12:27:33 pm

I do not condone drug usage. Never have, and never will, except from my Doctor!

What, you never put sugar in your coffee?

Berni · « **Reply #2 on:** July 30, 2020, 12:57:59 pm »

That is one very very tiny scale alright. But there are other uses than drugs for small scales.

Some people have chemistry as a hobby in the same was that a lot of people do electronics as a hobby and they do sometimes need to weigh out tiny amounts of stuff.

Very sensitive scales are scientific equipment in general, used for determining the amount of something. For example some of the hermetically sealed ceramic chips in the space program are tested by putting then under water under many bar of pressure for a while and then weighting them afterwards. If they gained a few milligrams of weight that means something got in. Sensitive scales can also be used to quantify tiny forces in experiments, like for example if you are building some sort of electrostatic actuator.

Some vinyl enthusiasts want to measure the tracking force of there record player to make sure its dialed in properly to not destroy records. This also needs a scale small enough to fit under the stylus and sensitive enough to measure down in fractions of a gram.

m98 · « **Reply #3 on:** July 30, 2020, 01:30:30 pm »

Ok, that car-key camoflage really is quite sketchy.
But those tiny scales are quite useful for making small batches of spice blends and weighing some food additives or food coloring. Fitness people who're into mixing their own supplements need fairly accurate scales. People who make their own soaps, cosmetics and perfumes.

A precise scale is a must-have for anyone whos into any form of applied chemistry, and then the choice is between the 10-20 € Ebay variant or the 500 - 2000 € name-brand lab scale.

TimFox · « **Reply #4 on:** July 30, 2020, 01:48:09 pm »

100 g is appropriate for weighing mail: US Mail prices go in 1 oz av = 28.4 g increments for first-class postage.
However the eBay vendor does not ship to US.

DrG · « **Reply #5 on:** July 30, 2020, 01:51:59 pm »

This one is obviously for weighing female to male stereo jack adapters.....I also found it "accidentally"

https://www.ebay.com/itm/0-01g-200g-Gram-Digital-LCD-Balance-Weight-Pocket-Scale-Weigh-Jewelry-and-Herb/323723622995?hash=item4b5f6e7a53:g:ac8AAOSwyHxcfwha

knotlogic · « **Reply #6 on:** July 30, 2020, 02:17:32 pm »

I was actually thinking about one of those a few days ago, figured it'd be useful for measuring out some epoxy. I only need a few grams mixed up, and the resolution on my kitchen scales only goes down to grams. The OP's one is really small though.

RoGeorge · « **Reply #7 on:** July 30, 2020, 02:32:02 pm »

I have in total 4 digital scales (and a few other scales with mechanical springs).

- One is a body weight scale, upto 200? kg, resolution 100 grams, good to see how fat I am
- One is a kitchen scale, upto 5 kg, resolution 1 gram, good for food recipes
- One is for upto 100 grams, resolution 0.1 gram - good for small items, medicine pills splitting, weed, gold jewelries
- One for upto 50 grams, resolution 1 milligram, good for chemistry, diamonds, precise medicine or chemicals mixing

Some dude needed a microgram balance to weight an eyelash, therefore he built one himself:

ledtester · « **Reply #8 on:** July 30, 2020, 02:44:21 pm »

Measuring out epoxy resin components:

https://youtu.be/e_ua18J8NOg?t=7m10s

rstofer · « **Reply #9 on:** July 30, 2020, 03:09:47 pm »

Scales like this are frequently used for measuring the powder charge when reloading ammunition. They are not preferred for a number of reasons (like reliability) and there are more appropriate scales for the task. But you can't beat the price!

This particular unit measures in 0.01 grams which is 0.15+ grains and we typically want to measure to the nearest 0.1 grain (and try to split that 0.1 gr when using a beam scale). This unit won't do that.

FWIW, there are 7,000 grains in a pound.

NivagSwerdna · « **Reply #10 on:** July 30, 2020, 03:28:24 pm »

I have one of these and use it for measuring panacur for tortoise de-worming... I'm surprised everyone doesn't have one.

themadhippy · « **Reply #11 on:** July 30, 2020, 03:55:34 pm »

Ive got a set similar to those for measuring white powder,and a freezer full of green leaf material.But having brewing salts and hops in the uk isn't illegal

BravoV · « **Reply #12 on:** July 30, 2020, 04:00:26 pm »

For what ?

Clearly ... obviously .. for you to spam general chat area.

SiliconWizard · « **Reply #13 on:** July 30, 2020, 04:17:02 pm »

Well, I don't know, this one seems very small indeed. But I do have a small (but still larger than this) precision scale that can take up to 2 kg, and it's handy in your lab - when you need to accurately weigh components/boards with better than 1 g accuracy.

100 g max seems pretty low, but it could still find uses in your lab, for weighing electronic components, (small) boards, chemicals when you need to make accurate mixes, etc.

Siwastaja · « **Reply #14 on:** July 30, 2020, 04:43:13 pm »

Oh boy was I delighted when I could buy Chinese precision scales in, uhm, 2008 I think? Dealextreme was a fairly new thing, then I found out about Ebay selling this Chinese crap. (Crap being used in positive meaning, this is.)

I got a 0.01g resolution, max 300g scale first, then a 0.1g resolution, 2000g one, and finally, a 0.001g 20g thing. All below $10 IIRC, and they all came with calibration weighs. None of them are as good as $1000 scales with similar specifications, but no ones expecting that. The bang-for-buck is great.

Even the first one still works, after over 10 years of almost daily use. I check the calibration every few years. These seem to be repeatable, I would even dare to suggest accurate, to about +/- 3 least significant digits and have a minimum measurable offset of about 7-10 least significant digits.

What for?

Yes, I did some chemistry as a hobby and later professionally as well. Was developing films and built a motion picture film processing lab. Of course, for the short while as a professional motion lab, I mostly used prepackaged Kodak kit chemistry but I still mixed some solutions like black & white developers or experimental processing solutions from scratch. I also experimented doing the film itself, this is, black&white emulsions from scratch, using food grade gelatine, silver nitrate made from dissolving silver into nitric acid (beware: deadly gasses emerge!), bromide and iodine salts and some other special sensitizing agents I already forgot about. The combo of science + art of growing the microscopic silver halide crystals through careful process control (temperatures, stirring, chemical injection rates), affecting the film's sensitivity, graininess and resolution, was indeed interesting. A strange mix of very low and high tech, when you can produce a 100-megapixel equivalent image by a process consisting of only mixing basic chemicals. This is how it worked for well over 100 years - and of course, it still works.

Now I mostly use the scales for weighing coffee. 24 grams per 0.5 liter of water, oh yes.

madires · « **Reply #15 on:** July 30, 2020, 04:54:27 pm »

... for counting electronic components the easy way.

rdl · « **Reply #16 on:** July 30, 2020, 05:47:01 pm »

I have a scale similar to that for weighing chemicals. The amounts needed to mix small batches of hydroponic nutrient solutions can be pretty small.

dnwheeler · « **Reply #17 on:** July 30, 2020, 05:49:32 pm »

Coin collectors have small scales to help detect counterfeit coins.

RoGeorge · « **Reply #18 on:** July 30, 2020, 06:22:45 pm »

Again, my 0.1g resolution was bought for weed checking, very, very long time ago. It was nothing wrong about it.

David Hess · « **Reply #19 on:** July 30, 2020, 06:33:41 pm »

I use mine mostly for grading cases and bullets and for weighing power charges when reloading.

james_s · « **Reply #20 on:** July 30, 2020, 06:41:47 pm »

That looks a lot like the scale I use to measure the tracking force on turntable needles.

SilverSolder · « **Reply #21 on:** July 30, 2020, 09:10:34 pm »

Some more use cases here:

1) Weighing ink cartridges (for inkjet printers) so I know when they are running low and ready to refill...

2) Weighing yogurt culture powder

3) Weighing yeast powder

Alex Eisenhut · « **Reply #22 on:** July 30, 2020, 09:32:19 pm »

I was weighing quadcopter blades for reasons. Turns out it makes no difference as far as I could tell...
Then I got a blade balancer and the motor was shaking more with a balanced blade.
Now I don't weigh anything anymore.

Macbeth · « **Reply #23 on:** July 30, 2020, 10:32:58 pm »

No drug dealer would ever bother with 0.01g resolution. Before these cheap electronic scales a low end dealer would just use a traditional small beam balance scale and the "calibrated" 1 gram weight would be a single cigarette out of a 20 pack (which would be 1g +/- 0.2g). They would put their finger on the scale anyway.

It's absurd to think these electronic devices are for common drug dealers.

Having said that, they may be useful to a Carfentinal dealer (usually the CCP) who decides on providing samples to a top level Mexican cartel gang? The kind of people who will do an LD50 test on the local populace before diluting it 10,000 times to sell as street heroin? I'm sure these billionaires are very happy that they can save a few hundred bucks on AliExpress.

themadhippy · « **Reply #24 on:** July 30, 2020, 10:48:14 pm »

no need for fancy weights to check your weed deals,1 uk penny=1/8 and 2p =1/4

coppice · « **Reply #25 on:** July 30, 2020, 10:56:41 pm »

Weighing 99.99% pure gold jewelery creates a substantial market for these small scales in East Asia, but there are many other uses. There are some kitchen scales with a small secondary scale like this integrated next to the main pad, to allow precise measurement of things like a few grams of yeast or herbs.

wraper · « **Reply #26 on:** July 30, 2020, 11:00:20 pm »

Counting parts. Instead of counting hundreds of parts as an idiot, weight one (or a few for better precision), then weight all of the parts, calculate total number number.

joeqsmith · « **Reply #27 on:** July 30, 2020, 11:52:44 pm »

I have a few smaller ones that I use to measure how full my small nitrous bottles are. I have an old balance in the lab that I use to measure clutch parts.

You can also use them to measure torque.

Halcyon · « **Reply #28 on:** July 31, 2020, 12:35:49 am »

Quote from: GlennSprigg on July 30, 2020, 12:27:33 pm

I do not condone drug usage. Never have, and never will, except from my Doctor!

You hit the nail on the head. Street-level dealers often carry these.

Alex Eisenhut · « **Reply #29 on:** July 31, 2020, 01:19:41 am »

Quote from: wraper on July 30, 2020, 11:00:20 pm

Counting parts. Instead of counting hundreds of parts as an idiot, weight one (or a few for better precision), then weight all of the parts, calculate total number number.

That's legit, but the problem for me was that I forgot how to tell my scale to enter counting mode. Something about putting 25 parts down first but if you don't know what to press it's quite cryptic and I lost the little 2cm x 2cm "manual".

lesson: always scan whatever papers you get asap!

Brumby · « **Reply #30 on:** July 31, 2020, 03:03:15 am »

Aside from the body scale in the bathroom, I have a range of digital scales from 5kg/1g down to 20g/1mg. The only time I've used any for drugs is when I needed to prepare 1/4 of a tablet of some medication for our dog, when the tablet didn't break cleanly in the pill cutter.

Two units have been modified to become computer connected - a 3kg/0.1g scale using an Arduino compatible MEGA board with a barcode reader for recording weights of barcoded products. The other was a 20g/1mg scale with an Arduino compatible Nano doing timed sampling for an evaporation study.

I do have one very small one which is a bit bigger than the tiny one shown above, but it played up, so it got put aside. Then one day a year or so later, I came across it and tried it again ... and it worked. This saved it from the bin - but I don't have any confidence in the stupid thing, so it will probably rot away.

dkim5nu · « **Reply #31 on:** July 31, 2020, 09:25:05 am »

Reloading (manufacturing ammunition for guns) requires precise measurement of explosive powders. For example, 9mm round requires a range of 3 to 5 grains of explosive powder inside its shell casing behind a projectile. There are 7000 grains in one pound and 454 grams in a pound, so that's about 0.195 grams to 0.324 grams per round of 9mm. Anything more than that, the ammunition is going to blow up your hands.

Strand17 · « **Reply #32 on:** July 31, 2020, 09:01:45 pm »

Hello,

People who fly rubber powered model airplanes indoors use this kind of scales. We are no big market, but still...

One example of the model airplanes we fly is the F1D competition class. The minimum weight of the structure (airframe) for a 55 cm wing span aircraft is 1.4 grams and the rubber motor (rubber band loop) must weigh no more than 0.4 grams. Flight times range from 15 to 40 minutes depending on the height of the ceiling and the flying conditions. Since we travel to competitions, portable scales are really helpful.

In fact 0.01 gram resolution is a bit coarse when keeping track of the weight of structural parts when building to a target weight or when preparing rubber motors.

Here is a link to a video a which conveys a bit of the feeling of indoor freeflight.

Best regards,

Jonas

KL27x · « **Reply #33 on:** July 31, 2020, 11:44:44 pm »

Quote from: wraper on July 30, 2020, 11:00:20 pm

Counting parts. Instead of counting hundreds of parts as an idiot, weight one (or a few for better precision), then weight all of the parts, calculate total number number.

This is my most common use for my scale. But the first pic of the thread? It's a little confusing, but doesn't it look like a mini pocket scale disguised as a key fob?

The obvious purpose is to disguise it from the popo, no?

KL27x · « **Reply #34 on:** July 31, 2020, 11:59:19 pm »

Or boss, or coworkers, or family.

ebastler · « **Reply #35 on:** August 03, 2020, 05:27:09 am »

Quote from: Strand17 on July 31, 2020, 09:01:45 pm

Here is a link to a video a which conveys a bit of the feeling of indoor freeflight.

Nice! At the risk of taking this thread off-topic a bit, I'm wondering about two things:

Why would there be a minimum weight for the planes? If you can manage to make it even lighter while keeping enough structural stability, isn't that a worthy achievement?

Why don't all flights end by the plane crashing into a wall after a relatively short time? I assume that you set the tail unit such that the plane goes round in circles. But I would have thought that you can't control the trajectory well enough to keep a plane away from the walls for tens of minutes?

GlennSprigg · « **Reply #36 on:** August 04, 2020, 01:20:09 pm »

Quote from: BravoV on July 30, 2020, 04:00:26 pm

For what ?

Clearly ... obviously .. for you to spam general chat area.

O.P. here. ?? Huh!!?? 'Spam'??... I'm obviously old & senile, but I do not understand your 'comment', mate?

Why are 'some' people like you so angry?? Don't know you from a bar of soap?... Maybe you, (but
luckily not ANYONE else here?) miss-understood the inflection of tone in my Title, and my tongue-
in-cheek text that followed. Of COURSE I know there are numerous uses for such scales, for which
I'm thankful for the numerous other informative replies.

(Other than the 'obvious').
My 'For what?', was meant as a rising inflection jokingly meaning 'what else!', and was posted in fun,
although surprised at the miniature car-remote 'look', where it's use was obvious??...

OH!! I get it!! Over 10,000 posts... Demi-God... Ivory Towers... Belittling-101... Are you proud?
Thanks to everyone else !!

Mr. Scram · « **Reply #37 on:** August 04, 2020, 01:35:45 pm »

I weigh components I modelled to see whether I'm close enough. If the weight is close the model is more likely to be too. Weighing things like plugs or pins isn't really an option when your scale only does grams.

Mr. Scram · « **Reply #38 on:** August 04, 2020, 01:37:41 pm »

Quote from: GlennSprigg on August 04, 2020, 01:20:09 pm

O.P. here. ?? Huh!!?? 'Spam'??... I'm obviously old & senile, but I do not understand your 'comment', mate?
Why are 'some' people like you so angry?? Don't know you from a bar of soap?... Maybe you, (but
luckily not ANYONE else here?) miss-understood the inflection of tone in my Title, and my tongue-
in-cheek text that followed. Of COURSE I know there are numerous uses for such scales, for which
I'm thankful for the numerous other informative replies. (Other than the 'obvious').
My 'For what?', was meant as a rising inflection jokingly meaning 'what else!', and was posted in fun,
although surprised at the miniature car-remote 'look', where it's use was obvious??...

OH!! I get it!! Over 10,000 posts... Demi-God... Ivory Towers... Belittling-101... Are you proud?
Thanks to everyone else !!

What are you on about?

GlennSprigg · « **Reply #39 on:** August 04, 2020, 02:17:23 pm »

Quote from: Mr. Scram on August 04, 2020, 01:37:41 pm

Quote from: GlennSprigg on August 04, 2020, 01:20:09 pm
O.P. here. ?? Huh!!?? 'Spam'??... I'm obviously old & senile, but I do not understand your 'comment', mate?
Why are 'some' people like you so angry?? Don't know you from a bar of soap?... Maybe you, (but
luckily not ANYONE else here?) miss-understood the inflection of tone in my Title, and my tongue-
in-cheek text that followed. Of COURSE I know there are numerous uses for such scales, for which
I'm thankful for the numerous other informative replies. (Other than the 'obvious').
My 'For what?', was meant as a rising inflection jokingly meaning 'what else!', and was posted in fun,
although surprised at the miniature car-remote 'look', where it's use was obvious??...

OH!! I get it!! Over 10,000 posts... Demi-God... Ivory Towers... Belittling-101... Are you proud?
Thanks to everyone else !!
What are you on about?

Not aimed at you mate.... Have a good day!!

Mr. Scram · « **Reply #40 on:** August 04, 2020, 02:29:07 pm »

Quote from: GlennSprigg on August 04, 2020, 02:17:23 pm

Not aimed at you mate.... Have a good day!!

It doesn't make sense either way.

Simon_RL · « **Reply #41 on:** August 04, 2020, 03:02:51 pm »

I used to use a similar scale when I was into target archery for arrow building. I was important to get each arrow weight as close to each other as possible to ensure consistent fight across a set of six + 2 spare arrows. That scale measured in both grams and grains, can't remember the resolution now.

TimFox · « **Reply #42 on:** August 04, 2020, 03:17:34 pm »

I read an interesting use for weighing scales in a biography of Henry Ford and his motor company. At the beginning of WW II, the company management was somewhat chaotic and the Army sent Henry Ford II back to civilian life to fix things, since Ford Motor Co was important to the war effort. He found that accounting was keeping track of accounts payable by weighing the paper invoices (as some here weigh bags of components to count them). The author noted that that this was not as dumb as it sounds, since accounting had previously calibrated this process to get an acceptable estimate of the cash flow.
Robert Lacey: Ford, the men and the machine Boston: Little, Brown & Co 1986. pp 429-430.

El Rubio · « **Reply #43 on:** August 08, 2020, 06:18:33 pm »

Quote from: dkim5nu on July 31, 2020, 09:25:05 am

Reloading (manufacturing ammunition for guns) requires precise measurement of explosive powders. For example, 9mm round requires a range of 3 to 5 grains of explosive powder inside its shell casing behind a projectile. There are 7000 grains in one pound and 454 grams in a pound, so that's about 0.195 grams to 0.324 grams per round of 9mm. Anything more than that, the ammunition is going to blow up your hands.

Not necessarily. I have been reloading since about 1985. I currently use a cheap digital scale supposedly accurate to 1grain The problem is if you are trying to measure 4.2 grains for one of those 9mm rounds. 3-5grains is unacceptable. I am not worried about 5 grains damaging the gun as much as the desire for accurate and consistent loads. I use this method to increase the accuracy of my powder charges. For those of you not familiar, measuring gunpowder is done with a simple device that usually has an adjustable cavity that is filled with powder. You measure the powder by volume and adjust until it is what you want- say 4.2 grains. You may use different powders for different loads and they weigh differently. Back to my method. I Adjust the powder measure to throw 4.2 grains according the cheap scale. Then, I throw ten charges and measure them all together. It should weigh 42grains. I fine tune the powder measure until 10 throws are as close to 42grains as possible. Now if my scale is off by a grain, it is only 1/10th of a grain per charge. 4.1-4.3 is fine.
Getting back to overcharging rounds. 9mm is not a great example because the case is so small. You can definitely overcharge a 9mm, but I have not used a powder that would even fit a double charge into a 9mm case. I had concerns using “Unique” powder for 9mm once because the 5-6 grains called for nearly filled the case. I was concerned that seating the bullet would compress the powder which is something you don’t want to do. There’s a lot of space in a 357mag and that could get dangerous. Especially since most 357 owners will also run 38special. The cases are the same except the 357 is a little longer. It is quite possible to load a 38 with a 357 charge if you aren’t paying attention, but I don’t know anyone that doesn’t double or triple check things like that when reloading. I read about the 10x measurement back in 80’s when I used an analog RCBS scale and have used it since.

jimdeane · « **Reply #44 on:** August 08, 2020, 06:56:07 pm »

I felt a little odd buying a cheap milligram-precision digital scale in my last Amazon order. But my use IS drugs -- measuring the weight of my asthma inhaler after doses to determine if the dosage is consistent throught the range from new to last dose. (I suspect it is not -- I have much worse symptoms in the last week or so of use.) If my data supports my hypothesis I can then submit a stronger argument to the FDA and the manufacturer that there is a problem.

coppercone2 · « **Reply #45 on:** August 13, 2020, 07:28:19 am »

there is another awesome use for digital scales

its called measuring chemicals for reactions

SilverSolder · « **Reply #46 on:** August 13, 2020, 01:18:35 pm »

Quote from: coppercone2 on August 13, 2020, 07:28:19 am

there is another awesome use for digital scales

its called measuring chemicals for reactions

That's what we do in the kitchen every day?

wraper · « **Reply #47 on:** August 13, 2020, 02:19:26 pm »

How about simply measuring components of 2 part adhesives.

asmi · « **Reply #48 on:** August 13, 2020, 02:22:00 pm »

I wonder if you can use it to determine if magic smoke escaped the ICs you are about to solder. It's got to weigh something, right?

madires · « **Reply #49 on:** August 13, 2020, 02:32:04 pm »

... or you need one for your top-secret flux recipe which is passed down in your family for generations.

edy · « **Reply #50 on:** August 13, 2020, 03:30:50 pm »

I read through the entire thread but didn't seem to find anyone questioning the accuracy of these scales.

1. What method do they use to measure weight?
2. How well are they calibrated?
3. Has anyone independently checked how accurate they are?
4. Does weight differ depending on where on the scale it is placed?
5. How will repeated use/battery levels, etc... change the sensitivity/accuracy over time?

It is interesting to have a tiny scale (maybe more useful to have the 500g version although not as portable, https://www.ebay.com.au/itm/Portable-500g-x-0-01g-Mini-Digital-Scale-Jewelry-Pocket-Balance-Weight-Gram/223652841494)...

....but in as much as these ARE MEASUREMENT DEVICES, the only thing that matters to me is that they actually do the job accurately, consistently and do not drift over time. Has anyone bothered to check or test this out yet?

Besides drug use, they can be used to measure out quantities of gunpowder and other materials for use in reloading ammunitions:

HighVoltage · « **Reply #51 on:** August 13, 2020, 03:49:51 pm »

A few years ago, I bought a used precision KERN scale, Made in Germany, that was offered as broken.
And I thought I could easily repair it.
But it was a one-chip system with epoxy (Like in cheap calculators) and the wires were so stiff that they all broke during the disassembly process.

After that I bought a real precision scale from Mettler Toledo, Made in Switzerland.
This one can measure down to 0.1 mg and is made rock solid.

I use these scales for mixing of chemicals and measuring the loss of metal on electrodes during electrolysis.

edy · « **Reply #52 on:** August 13, 2020, 04:55:35 pm »

Quote from: HighVoltage on August 13, 2020, 03:49:51 pm

After that I bought a real precision scale from Mettler Toledo, Made in Switzerland.
This one can measure down to 0.1 mg and is made rock solid.
I use these scales for mixing of chemicals and measuring the loss of metal on electrodes during electrolysis.

Exactly my point... yes sure for measuring street drugs I don't think people care about the accuracy. Maybe even gunpowder grains, if you are off a bit you might not have a huge difference. So these cheap-o scales may be good enough. But how good/bad? I'd like a thorough side-by-side to a quality instrument.

Like when Dave does a side-by-side with a cheap-o $100 pocket oscilloscope's claims against one of his $2000 oscilloscopes, or the cheap-o multimeters. Sure it may be worth the price... nothing wrong there. But I'd still like to know what kind of error I'm dealing with.

jfiresto · « **Reply #53 on:** August 13, 2020, 05:42:33 pm »

Quote from: edy on August 13, 2020, 03:30:50 pm

I read through the entire thread but didn't seem to find anyone questioning the accuracy of these scales....

I bought a Soehnle, 1000 count, 0-2000 gram kitchen scale, back when they were still made in Switzerland. It uses a simple strain gauge sensor which over the last 27 years has drifted about 1%, so that a 1000 gram calibration weight now reads 1011 gram. Unfortunately, like most consumer scales, the end user has no way to recalibrate it.

After the drift had become noticeable, I picked up a lightly used, 21000 count, 2100 gram, Mettler Toledo industrial balance, along with a class F1, 2 kg calibration weight.

The balance has a bubble level to help you get the pan horizontal and calibration modes to adjust for long term drift and the local gravitation acceleration. You can run the balance off battery, but it is really prefers to run off AC and left on standby and stabilized. The balance is sensitive to temperature rather than supply voltage changes.

The balance has an internal calibration weight, which matched and still matches the 2 kg weight. A couple years ago, our friendly local Eichamt (office of weights and measures) compared the 2 kg weight to their standard and found them in agreement to within F2, the next looser accuracy class. So, I am reasonably confident that the balance is within somewhat more than 100 mg of true. For fun, I have made up packages so that they weigh 999.7 g, taken them to our local postal agent and watched as they eventually round up to 1000 g on their scales.

I use the balance for cooking, weighing adhesive and such, but also to weigh out my Muesli each morning. I started doing that after the Muesli makers reduced the amount they put in a box. Now when they do that, I reduce the amount I eat (and buy) proportionally. Tit for tat.

Perhaps that answer your questions.

edy · « **Reply #54 on:** August 13, 2020, 07:25:14 pm »

Quote from: jfiresto on August 13, 2020, 05:42:33 pm

Perhaps that answer your questions.

I'm sure the Soehnle and Mettler Toledo are much higher quality, accuracy and with a commensurately higher cost than the $8 hand-held "car remote" scales being sold on eBay. So my question is partly answered... that is, if these much better scales still drift and have inaccuracies and need some calibration and lots of adjustments for different environmental/geographic conditions, what chance does a cheap-o eBay pocket scale have?

We need a head-to-head "weigh off" with a bunch of known standards across the entire range of such a scale, and compare it to a professional quality or even medium-range cost scale. The fact that the cheap-o scale gives me readings down to the 0.01g means nothing. Here is an example:

Here is the listing, all yours for $6.99:

https://www.ebay.com/itm/Portable-LCD-Mini-Digital-Scale-Jewelry-Pocket-Balance-Weight-Gram-0-01g-500g/283934412103

Read in the description:

Quote

Capacity: 0.1g~500g; 0.01~500g;0.01-200g
Division value: 0.01g/(Note: if The precision is 0.1g, but the minimum measuring weight is 0.5g
If The precision is 0.01g, but the minimum measuring weight is 0.05g and it is true of all the digital scales, pls kindly note it, tks!)

What does that even mean? I think they are saying for scales that say 0.01g you can measure down to 0.05g (so you don't expect to be measuring 0.04g and below). And for scales that say 0.1g, you can't actually measure anything less than 0.5g.

So let's take our $6.99 500g/0.01g scale and put it head-to-head with an actual quality scientific instrument and see how it does measuring everything from 0.05g up to 500g in various increments. It's easy to make a set of weights... just divide and conquer... get these standard weights and then put one or several on the scale and you can get to any possible weight range within 500g:

250g
125g
60g
30g
15g
10g
5g
2g
1g
0.5g
0.1g
0.05g

I'd like to know how accurate the $6.99 scale is. Hey, it may be worth $6.99 even if it comes with a HUGE ERROR... just depends what you want to use it for. But it seems nobody seems to know. After some testing we may find the error even varies along the range of weights. We may find the last few "precision digits" are complete garbage. If the scale is GREAT at say between 100-200g, and I have trivial tasks I need that are not high precision, then wonderful. But who actually has tested anything out?

I'll give you another example... say you buy a cheap-o eBay mechanical watch that has pretty bad time keeping. If you are someone who just wants to know the "approximate" time at a glance and the watch was cheap and looked nice, you wouldn't care. But what if accurate time was more critical? What if a watch that cost 2x more but would be 10x more accurate made the difference between you miss a train or not? Before you bought the watch that was $5, $10, $20 or $100, wouldn't you want to really KNOW?

I feel like these cheaper scales are not possible to trust the specs on. They may be fine, or they may be lying. They may actually be quite good for the price.... but who has bothered to test any of them?

And here is an excellent article about someone who loads up gunpowder in his ammunition which I assume has to be a very accurate procedure as they say explicitly on the page that THEY DON'T USE ELECTRONIC SCALES due to their inaccuracy/inconsistency:

https://www.celnav.de/muzzleloaders/powder_measurement.htm

On the topic of rifles... another example could be 2 air-rifles, one that lets you shoot a dime consistently at 20 yards, versus another cheap-o air-rifle which no matter how hard you try aiming, has an error that will not tighten your shot grouping to less than a beer bottle. How far off from the center-target would be your accuracy (which you should be able to correct with a well-calibrated scope), and the tightness of your shot groupings would be your precision.... That may be a function of the quality of your air-rifle, due to the machining of the barrel, the shape and consistency along the length, how reproducible the air pressures are for each shot, and so on.

Bud · « **Reply #55 on:** August 13, 2020, 08:10:26 pm »

Learn what this youtuber used his precision scale for. Though the scale is optomechanical, not digital, but it is a quite elaborate device The way he sourced the test materials for the experiment may make you throw up though

https://youtu.be/eKsEmukmByI

SilverSolder · « **Reply #56 on:** August 13, 2020, 08:32:16 pm »

Quote from: jfiresto on August 13, 2020, 05:42:33 pm

[...]
I use the balance for cooking, weighing adhesive and such, but also to weigh out my Muesli each morning. I started doing that after the Muesli makers reduced the amount they put in a box. Now when they do that, I reduce the amount I eat (and buy) proportionally. Tit for tat.
[...]

The Muesli that I buy, is sold by weight, not volume - so weighing it wouldn't help me!

HighVoltage · « **Reply #57 on:** August 14, 2020, 08:17:02 am »

One other applications for precision scales I had over the years was to certify magnets
I had a magnetic disc above the magnet on the scale and measured the difference in weight.
The disk height can be adjusted by a micrometer.

For this I used a precision scale from Bosch

Circlotron · « **Reply #58 on:** August 14, 2020, 08:30:42 am »

Useful for weighing several tens of grams of mass to add to a loudspeaker to measure Thiele and Small parameters.

My spreadsheet for calculating such:
https://www.diyaudio.com/forums/multi-way/24864-parameter-spreadsheet.html#post353269

GlennSprigg · « **Reply #59 on:** August 16, 2020, 12:49:04 pm »

O.P. here...
To various posters/replies, yea I doubt the ones I first mentioned would really be that accurate, but who knows!

My main point was that being the size/look of a Car Remote on a keyring, indicated the 'intended' market, haha...

Mind you, I'm glad to hear from others that there are so many other real & practical uses for a need for small measurements!!
Actually, I just had flash-backs to High-School Chemistry, (nearly 50 years ago!), when we had to weigh the resultant components after
certain reactions/combustions, as a 'proof' of the calculated atomic results. No such accurate digital 'scales' back then!!

HighVoltage · « **Reply #60 on:** August 16, 2020, 01:47:04 pm »

One thing that usually is overlooked when using a precision scale is air weight displacement by the part that is being measured.

jfiresto · « **Reply #61 on:** August 16, 2020, 02:11:15 pm »

From Robert W. Shaw (1980) Balance Corrections for Buoyancy, Journal of the Air Pollution Control Association, 30:8, 908-909, DOI: 10.1080/00022470.1980.10465130:

Quote

In conclusion, conditions may occur when buoyancy corrections to weight changes become significant. An object with a specific gravity of 1 or 2 and a volume of several cubic centimeters may appear to change its weight by amounts on the order of 0.2 mg merely because of changes in the weather and consequent changes in air density. Anyone involved in high accuracy weight determinations should calculate the appropriate buoyancy corrections and keep track of local air density during gravimetric determinations.

David Hess · « **Reply #62 on:** August 17, 2020, 01:58:04 am »

Quote from: HighVoltage on August 16, 2020, 01:47:04 pm

One thing that usually is overlooked when using a precision scale is air weight displacement by the part that is being measured.

"Ha, look! After pressing down on the scale, it did not return to zero!"

"That is the weight of your fingerprint."

bson · « **Reply #63 on:** August 17, 2020, 03:20:40 am »

I have several gram scales and use them for all kinds of things... Most recently I was curious exactly how much 2 g of salt (NaCl) is.

coppercone2 · « **Reply #64 on:** August 17, 2020, 05:28:06 am »

Quote from: bson on August 17, 2020, 03:20:40 am

I have several gram scales and use them for all kinds of things... Most recently I was curious exactly how much 2 g of salt (NaCl) is.

you know, if you have health problems, its a good way to measure how much salt you are adding to your food in a restaurant. Or sugar, for diabetics.

There is too many options, sea salt, granuated sugar, powdered sugar, crystal sugar (brown), syrup packets, honey packets, kosher salt (served in a bowl often), different grinds of salt. You can't measure it with a spoon to medical requirements. I.e. salad bar food prep (temporarily out of style due to disease). Nothing there should be seasoned, theoretically you can get a vegetable salad, add only oil, then salt it to the correct amount for taste and diet. Some doctors argue you should meter the amount of salt you eat very well, even if you have no medical problems. So many people have high blood pressure.

jh15 · « **Reply #65 on:** August 21, 2020, 12:01:28 pm »

I would like a discrete scale you could use at a restaurant.
Is it cheaper by the cup or bowl for example.
A flat load cell/platform that wouldn't be noticeable.
Somehow a readout with tare after food is consumed. These days to your phone, but any readout is good for me.
Been thinking decades ago of using a strain gauge, but recently adapting these mini scales.
There. Now someone start a kickstarter.
Also to be fancy, could automatically go to a spreadsheet to figure cost per weight of steak at restaurant A compared to B, etc.

ace1903 · « **Reply #66 on:** September 17, 2020, 11:46:59 am »

I looked for long time for precise measurement of NaOH that I am using as a developer for Positiv20 spray.
Found device that audiophiles use for turntable evaluation.

Does anyone know if this device can be reused for measuring small quantities in chemistry?
https://www.amazon.com/Cuiedailqhb-Portable-Digital-Turntable-Tracking/dp/B0832ZV5KR?th=1

Anyone that made tear-down or knows measurement principle used in that device? S shaped aluminium with resistive sensors is very unlikely to be used.

jfiresto · « **Reply #67 on:** September 17, 2020, 01:51:12 pm »

That is only a 500 count scale which probably keeps the cost down. You might ponder a scale's uses and aim for one that is a little more ambitious if you think it might have other uses.

Commercial and even consumer scales typically do better, offering 3000 and 1000 counts, respectively. Good industrial and laboratory scales can routinely manage two to three orders of magnitude better, with a lab scale offering half a million useful counts of resolution being nothing extraordinary.

jogri · « **Reply #68 on:** September 17, 2020, 09:21:37 pm »

Quote from: ace1903 on September 17, 2020, 11:46:59 am

I looked for long time for precise measurement of NaOH that I am using as a developer for Positiv20 spray.
Found device that audiophiles use for turntable evaluation.

Does anyone know if this device can be reused for measuring small quantities in chemistry?
https://www.amazon.com/Cuiedailqhb-Portable-Digital-Turntable-Tracking/dp/B0832ZV5KR?th=1

Anyone that made tear-down or knows measurement principle used in that device? S shaped aluminium with resistive sensors is very unlikely to be used.

Protip from a guy that has done that: Never try to weigh your NaOH if you want accurate measurements, that stuff is highly hygroscopic and trying to measure it accurately is a royal PITA as you have to remove the crust of every single pellet you are going to use as the crust mostly consists of water, screwing over your calculations... Oh, and it also collects the CO2 in the air to form sodium carbonate, and you won't get that stuff off by simply heating it.

If you want to make a solution with a known concentration you have two options:
-Make the solution and measure the concentration by a titration (can be done at home, but takes a bit of experience). Keep in mind that you will have a bit of sodium carbonate in it, so not a good idea if something is sensitive against that stuff
-Wash your NaOH before you use it: Take a bit of water, rinse the pellets/nuggets and dump that water, then heat it in a drying oven (but not for too long as it will start to collect CO2 from the air), then weigh your dry NaOH and add the required amount of DI water. Not as precise as doing a titration, but more than good enough for most applications

ace1903 · « **Reply #69 on:** September 18, 2020, 06:50:13 am »

Usually I buy ecofriendly developer for photoresist that only needs to be diluted with 1l distilled water.
But due to problems with shipping I switched back to local supplier for chemicals.
Fortunately I don't need extremely precise measurement since process is tolerant to range of concentrations.
7g is at low side on those 200g range 0.01g resolution scales and I don't want to keep several liters of NaOH.

Could you please provide info what is used to titrate NaOH? I already have set of lab glassware and maybe 30 chemicals.

I hoped that this 5g scale will have better resolution since I am close to max range. But I didn't notice this 500 counts limit.
Is this resolution limit of the measurement principle or I can override it with some 16bit ADC and nucleo board that I have on disposal?

jmh · « **Reply #70 on:** September 18, 2020, 08:49:07 am »

I got one from eBay of the type you see on 'police camera action' type programmes to weigh gemstones, but the only use it sees these days is to weigh the occasional letter and to weigh our hamsters!

jogri · « **Reply #71 on:** September 18, 2020, 10:57:25 am »

Quote from: ace1903 on September 18, 2020, 06:50:13 am

Could you please provide info what is used to titrate NaOH? I already have set of lab glassware and maybe 30 chemicals.

The standard approach would be to use muriatic acid with a known concentration, but since you probably don't have that you have to make a primary standard: That's a solution with a known concentration, made by dissolving a substance that isn't hygroscopic (and therefore has a known density and molecular weight)->if you weigh the amount of substance that you dissolved in x litres of water you can calculate the precise concentration of your solution. You then use this primary standard to titrate your NaOH solution.

You could use almost every pure chemical that is stable in air, doesn't have an unknown amount of crystal water and that forms an acid when you toss it in water, but the two substances that get used in chemistry labs for this job are potassium hydrogen phthalate (KHP) and oxalic acid dihydrate. Use phenolphthalein as the indicator, and make sure that you will use between 10-30ml of acid for your titration if you want precise results (you can always dilute your NaOH but the primary standards don't have a great solubility in water so you can't make a really concentrated solution).

Here is a paper that describes the process, just PM me if you have further questions: https://silo.tips/download/chemistry-111-laboratory-experiment-8-stoichiometry-in-solution-standardization

I personally wouldn't go this far just for a film developer as it will probably work just as good even with a +/- 10% deviation in the NaOH concentration, but a titration is a great exercise in precise lab work.

tom66 · « **Reply #72 on:** May 25, 2022, 10:58:24 pm »

My father had one of these to weigh jewelry. He was a gemologist though.

magic · « **Reply #73 on:** May 26, 2022, 01:06:22 pm »

Quote from: edy on August 13, 2020, 03:30:50 pm

I read through the entire thread but didn't seem to find anyone questioning the accuracy of these scales.

1. What method do they use to measure weight?
2. How well are they calibrated?
3. Has anyone independently checked how accurate they are?
4. Does weight differ depending on where on the scale it is placed?
5. How will repeated use/battery levels, etc... change the sensitivity/accuracy over time?

It is interesting to have a tiny scale (maybe more useful to have the 500g version although not as portable, https://www.ebay.com.au/itm/Portable-500g-x-0-01g-Mini-Digital-Scale-Jewelry-Pocket-Balance-Weight-Gram/223652841494)...

....but in as much as these ARE MEASUREMENT DEVICES, the only thing that matters to me is that they actually do the job accurately, consistently and do not drift over time. Has anyone bothered to check or test this out yet?

Besides drug use, they can be used to measure out quantities of gunpowder and other materials for use in reloading ammunitions:

You are going to love this thread:
https://www.eevblog.com/forum/dodgy-technology/i-cracked-the-mystery-of-chinese-precision-jewelry-scales/

I don't recommend using Chinese junk for dosing drugs

coppice · « **Reply #74 on:** June 14, 2022, 08:46:48 pm »

Quote from: pairfkup on June 14, 2022, 08:39:04 pm

Why are electronic scales considered the most convenient ?

They are clearly the most convenient, giving a quick numerical readout. However, I think they are mostly attractive because they just work so well. Try putting a kilo of something on several models of electronic scale that cost just a few dollars each and the spread of measurements is usually just 3 or 4 grams, and stays like that for a few years.

magic · « **Reply #75 on:** June 14, 2022, 08:54:34 pm »

Quote from: coppice on June 14, 2022, 08:46:48 pm

They are clearly the most convenient, giving a quick numerical readout. However, I think they are mostly attractive because they just work so well. Try putting a kilo of something on several models of electronic scale that cost just a few dollars each and the spread of measurements is usually just 3 or 4 grams, and stays like that for a few years.

If you are lucky, even your kilo being 3 or 4 grams off may still be within the scale's tolerance to display 1.000kg

ebastler · « **Reply #76 on:** June 14, 2022, 09:25:54 pm »

I am pretty sure that both "pairfkup" and "fidelitykurz" are spammers, who intend to add a spam link to their posts soon. New user, old thread, marginally relevant posts -- all the indicators are there. And I believe we have had more or less the same spam posts in this thread a few weeks ago, cleaned up by the mods in the meantime.

Both posts have been reported. I don't think there is much to be gained by replying to these.

SmallCog · « **Reply #77 on:** June 15, 2022, 12:04:27 pm »

I bought one of these pocket sized scales a few weeks back in order to check a pluviometer (rain gauge) test jig.

This is basically a jig that dribbles a measured quantity of water through the rain gauge.

I’ve always been slightly curious about the repeatability of this jig so I decided to weigh the water used to fill it over the last few weeks and to my shock when I followed the instruction to fill the chamber to overflowing it was exactly the amount the jig was supposed to hold.

Obviously not a laboratory grade instrument but it was a happy coincidence that it measured exactly what it was expected to (which isn’t a round number in grams, ends in a fraction) and that it’s been very repeatable


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