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URGENT! Digital Scales, 0.5g Accuracy, CHEAP! Who Wants?

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deandome

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I know this isn't the yard sale forum, but a) this isn't rocket-specific and b) I need to know by tomorrow who might want this, so I need a 'big' forum.

I came across about 6 digital, flatbed scales at a discount store (they may have more) that are PERFECT for epoxy mixing and lots of other things. They're perfect because they're accurate to 0.5 grams AND can handle all the way up to 2 kilos (4.4 lbs). Believe me...it's hard to find that combination of accuracy & capacity at a good price. I'm a rather obsessive comparison shopper, and I got mine w/the same exact specs for a few years ago for $50.

I'm pretty sure this is the exact model...it's the same brand & specs, but they were in sealed boxes w/a B&W photo on it: http://www.shopping.com/xPO-Learning-Resources-Electronic-Scale

I thought of scooping them up, but I don't want to get stuck w/them, so I thought I'd gauge demand first. They're $15 each, so I figure shipping/packing (I don't want to just stick a label on the factory box, I'll do it right) @ $4-7 each and a monster profit for me :p would make for $25 total, delivered to your door.

That's it! Respond here or PM me, and if there's some interest, I'll pick them up tomorrow. I'm set up for Paypal (only), but we'll discuss that once I hear from you.
 
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Queeg500

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nice! the $15 model I got off ebay last year had a rusty internal battery bay...:rolleyes: I kept it tho because I didn't want to go through the return hassles. You found these at a retail store?
 

deandome

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It's a once-a-year sale of educational toys & games at a warehouse in an industrial park (I think by Learning Resources..the mfg of the scale..but it could be a distributor).

All stuff is 100% sealed/new...the sale's advertised in the newspapers. No dudes in white panel vans!! :roll: I'll open it up and inspect/test before shipping, too.

I mentioned to Pippen that among all the stuff I can't rattle off here, they have our favorite family game, Blokus, for only $10!!! If you search WalMart/Target, I think it's $20-22..it's $25 @ Amazon & $30 at most toy stores. If you don't have it...GET IT...read the reviews here: http://www.amazon.com/dp/B001P06GX4/?tag=skimlinks_replacement-20 . If you're interested in this, I'll add it to a scale order for the $11 extra (the box will be more $$)..no increase in shipping/packing. We bought 4 of 'em for our 'future present' closet!
 
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powderburner

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If it is not too late, I would like one.

Will send a PM in a few minutes--
 

JonathanDunbar

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I know this isn't the yard sale forum, but a) this isn't rocket-specific and b) I need to know by tomorrow who might want this, so I need a 'big' forum.

I came across about 6 digital, flatbed scales at a discount store (they may have more) that are PERFECT for epoxy mixing and lots of other things. They're perfect because they're accurate to 0.5 grams AND can handle all the way up to 2 kilos (4.4 lbs). Believe me...it's hard to find that combination of accuracy & capacity at a good price. I'm a rather obsessive comparison shopper, and I got mine w/the same exact specs for a few years ago for $50.

I'm pretty sure this is the exact model...it's the same brand & specs, but they were in sealed boxes w/a B&W photo on it: http://www.shopping.com/xPO-Learning-Resources-Electronic-Scale

I thought of scooping them up, but I don't want to get stuck w/them, so I thought I'd gauge demand first. They're $15 each, so I figure shipping/packing (I don't want to just stick a label on the factory box, I'll do it right) @ $4-7 each and a monster profit for me :p would make for $25 total, delivered to your door.

That's it! Respond here or PM me, and if there's some interest, I'll pick them up tomorrow. I'm set up for Paypal (only), but we'll discuss that once I hear from you.

Dean,

You do know that Harbor Freight sells a digital pocket scale accurate to .1 gm and converts grams-oz-dwt-ozt, and has a capacity up to 500 grams for $7.99; every day price. The scale fits in my back pocket, and is large enough so I can easily take balsa sheets and weigh them as I am sorting through balsa looking for the lightest sheets.

I use it when I go to hobby shops and Michaels to buy balsa wood.

If one needs anything larger, there are digital scales up to 50 lbs on ebay for under $20! Here are a few:

http://cgi.ebay.com/35-LB-DIGITAL-S...emQQptZLH_DefaultDomain_0?hash=item518ee272b0

http://cgi.ebay.com/50-LB-DIGITAL-S...emQQptZLH_DefaultDomain_0?hash=item35a56dd600

No I am NOT the seller. Just passing on useful information to the community so that they can spend less on scales and more on rockets! :D

Jonathan
 
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deandome

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I explain that the main use for this scale...at least for me...is to weigh the components used in batches of epoxy (and expanding foam)...from little, one-fin batches of 4-8 grams (2-4 grams of A and B) to bigger 1-2 lb containers of West...where you also need accuracy to nail the hardener's tricky "1" in the 5-1 ratio accurately. A stainless table is pretty important..at least to me...so you can clean it w/solvents when you sometimes get lazy & forget to put the container on wax paper.

Neither of the ones you show are good for that; the pocket one is too small for the mid/large containers and has a plastic table...and the postal scale isn't accurate enough for, well...much at all besides maybe finished rockets at a RSO table...as it's stated accuracy of +/- 0.2 oz = 5.6 grams ...and it too has a plastic table.

For me, finding accuracy of .5 or .1 grams AND a capacity well above 500-1000 grams (and a decent-size steel table) was a bit tricky Here's an ebay source for one..it's 0.1 vs. 0.5, but it's also $50: http://cgi.ebay.com/Digital-Jewelry...emQQptZLH_DefaultDomain_0?hash=item5ad3d2cc48

BTW...when weighing components other than west that clearly state "by weight" is fine...other things like Bob Smith, expanding foams and especially JB Weld, (where one component has steel in it) usually assume you're going to measure by volume, or equivalent sized "wads" of goo. I don't like that..it's not accurate & cure times can get screwed up in small batches. So it's important to weigh the unopened containers to determine if their individual weights/densities of each component are close enough for a straight 50-50 ratio of weights, or if you need fo calculate something special, like 1.3 -1 to be accurate.


Dean,

You do know that Harbor Freight sells a digital pocket scale accurate to .1 gm and converts grams-oz-dwt-ozt, and has a capacity up to 500 grams for $7.99; every day price. The scale fits in my back pocket, and is large enough so I can easily take balsa sheets and weigh them as I am sorting through balsa looking for the lightest sheets.

I use it when I go to hobby shops and Michaels to buy balsa wood.

If one needs anything larger, there are digital scales up to 50 lbs on ebay for under $20! Here are a few:

http://cgi.ebay.com/35-LB-DIGITAL-S...emQQptZLH_DefaultDomain_0?hash=item518ee272b0

http://cgi.ebay.com/50-LB-DIGITAL-S...emQQptZLH_DefaultDomain_0?hash=item35a56dd600

No I am NOT the seller. Just passing on useful information to the community so that they can spend less on scales and more on rockets! :D

Jonathan
 
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JonathanDunbar

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Dean,

I don't know how you are doing your searches, but I am finding scales for under $20 with shipping, that do 1000 grams and greater:

http://cgi.ebay.com/0-1-1000-Gram-D...emQQptZLH_DefaultDomain_0?hash=item4a9cdbb150

http://cgi.ebay.com/1000-x-0-1-Gram...emQQptZLH_DefaultDomain_0?hash=item5637be319e

2000 gram:

http://cgi.ebay.com/0-1-X-2000-GRAM...emQQptZLH_DefaultDomain_0?hash=item3efa226ac1

http://cgi.ebay.com/0-1-X-2000-GRAM...ptZAU_Packing_Accessories?hash=item45ef403a55


I made sure to use different sellers because I want to make it clear that I am not PUSHING any one product or anyone price. I don't sell on ebay, I only buy.

The above listings are all under $20.00 with shipping. I am in NO WAY affiliated with the sellers... although I think I am going to pick up one maybe two for my own use in the not so near future :)

Oh, I mix epoxy and expanding foams by volume as molecular weights between the two components are different, so you have to use volume... well at least I do... don't know about the rest of the world :)

Jonathan
 

Verna

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Hey, that's a nice one and would be great for low-mid power. We got a free one years back when our office got new postal equipment. It was only about 6 months old at the time and we still use it.

If you don't have one, I'd recommend getting in on this one.

:)

Verna
www.vernarockets.com
 

powderburner

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Harbor Freight sells a digital pocket scale accurate to .1 gm and converts grams-oz-dwt-ozt, and has a capacity up to 500 grams for $7.99; every day price.
I have several of these from Harbor Freight, and they are great little electronic scales. I also like that this bigger one that Dean found has a bigger capacity, 4+ pounds. I think Dean found these at a decent price. Last but not least, I am basically not using ebay anymore.

But I do appreciate your work to check out the alternatives and bring them to our attention!
 

greenrocketfish

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Hey guys,
I am new to the forum but you guys just got me to thinking. The scales are are great and I know scales are important and necessary for many things but bear with me. I am 51 years old. I have been building custom fishing rods now since I was in high school. I am new to rockets but not to epoxy. I have noticed that you mentioned weighing hardener and resin. I have built rods for bass tournament fisherman, weekend warriors and old salts. My son lives in far S. Texas and fishes redfish tournaments numerous times a year and does not take great care of his stuff. I have used and hardener - resin mixed epoxy for years without one fault of the product. It is water proof, salt water proof, UV proof, tough as nails, will not fade paint or dyes in thread and can be sanded and painted and is as clear as glass. The best thing about it is that it is not expensive and has a long shelf life and is flexible.

I am not a salesman for this product but after looking at this form think it would be great! Let me know if anyone is interested. It is a great product and might be great for rocket building.
thanks, Lee :rolleyes:
 

deandome

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Again...those are a completely different 'class' of scale.

The table is 2.5" x 2.7"...hardly adequate for a one-quart size plastic mixing container (barely big enough for the Wendys "ketchup cups" I grab for small batches).

A pocket scale is a pocket scale. Show me something with a 6" x 6" or so table...where you can see the display when you have a big container on it, that has 2 kilo capacity and .1 or .5 g accuracy like the kind I'm talking about!! for $20 or less, delivered, then you might have a point.

Flatbed scales like this are also great for the weighing food/ingredients in the kitchen if you don't have a dedicated kitchen scale.


Dean,

I don't know how you are doing your searches, but I am finding scales for under $20 with shipping, that do 1000 grams and greater:

http://cgi.ebay.com/0-1-1000-Gram-D...emQQptZLH_DefaultDomain_0?hash=item4a9cdbb150

http://cgi.ebay.com/1000-x-0-1-Gram...emQQptZLH_DefaultDomain_0?hash=item5637be319e

2000 gram:

http://cgi.ebay.com/0-1-X-2000-GRAM...emQQptZLH_DefaultDomain_0?hash=item3efa226ac1

http://cgi.ebay.com/0-1-X-2000-GRAM...ptZAU_Packing_Accessories?hash=item45ef403a55


I made sure to use different sellers because I want to make it clear that I am not PUSHING any one product or anyone price. I don't sell on ebay, I only buy.

The above listings are all under $20.00 with shipping. I am in NO WAY affiliated with the sellers... although I think I am going to pick up one maybe two for my own use in the not so near future :)

Oh, I mix epoxy and expanding foams by volume as molecular weights between the two components are different, so you have to use volume... well at least I do... don't know about the rest of the world :)

Jonathan
 

deandome

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UPDATE:

I'm done for the week, but the sale is open next Sat/Sun, too, so if anyone's still interested, let me know. There were 3 left after the 3 I bought today, but they might have a lot more when they restock for next weeks sale.

It is indeed a Learning Resources 'warehouse sale' at their HQ in Vernon Hills, IL. Every Dec, for 3 consecutive weekends, they do this.

BTW, they were OUT of those Blokus games @ about 1:00 today. That's freaky, they had about 30 or so when we left on Sat at 4:00. Again...let me know if you want that, too, as they might restock them (we'd buy another 3-4!).

Thanks, all!
 

JonathanDunbar

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UPDATE:

I'm done for the week, but the sale is open next Sat/Sun, too, so if anyone's still interested, let me know. There were 3 left after the 3 I bought today, but they might have a lot more when they restock for next weeks sale.

It is indeed a Learning Resources 'warehouse sale' at their HQ in Vernon Hills, IL. Every Dec, for 3 consecutive weekends, they do this.

BTW, they were OUT of those Blokus games @ about 1:00 today. That's freaky, they had about 30 or so when we left on Sat at 4:00. Again...let me know if you want that, too, as they might restock them (we'd buy another 3-4!).

Thanks, all!
Dean,

Here is a scale, with a LARGE surface (8" x 8") for quart size glasses of liquids, does up to 35 lbs, thats a lot of epoxy, and does +- .1 oz (2.8 grams) sensitivity, black (shows wear and stains less than white/lighter colors), Large LCD Display, delivered for under $20.00.

http://cgi.ebay.com/35-LB-DIGITAL-S...emQQptZLH_DefaultDomain_0?hash=item35a578ac5e

There are more, but I will leave that up to the shopper to find :)

Hope this helps you and others, and I too will stop looking as I have found something to my liking and purchaed it. Won't say, but it is scale on par with the learning things model... just not as big a flat surface, but thats ok because I have a postal shipping scale for those really big items that obscure the LCD; its has a serparate LCD unit on a wire that you can set aside a couple feet away to view the weight.

This is similar to what I have but it is only scalable to 50 lbs:

http://cgi.ebay.com/150-LB-DIGITAL-...emQQptZLH_DefaultDomain_0?hash=item35a5789ace


Sometimes on my small scale with large items, I will place the item on the scale, turn on the unit, wait until it boots up, then lift the item off the scale. The reading will now show but with a '-' in front of the value. Best bet is for anyone who is doing LARGE jobs, is to have a scale where the LCD is on a seperate unit apart from the scale itself.

Point is that with a little patience and work, you can buy just about anything for next to nothing; estate sales, garage sales, buy direct from the OEM, get a resellers license or LLC business name and this will save you paying taxes (local/city/state and don't ask me to educate you on how this process works, you do have to do leg work and research on your own, Dean not you personally just to anyone in general) ... and if you think prices are low now ... 2010 will see even more lay-offs, higher unemployment, and even better deals for those who are patient.

I am just trying to get people to see that they can save a lot of $$$ and get more for their money if they just take the time to look around. Trust me, the scale sold by the learning things can be found elsewhere for the same if not less if you just look. Lerning Things isn't the only place on planet Earth that has these scales for sale at that or lower price. And there are scales, with more features, and greater flexibility for equal or slightly more money.

BTW, our markets are being FLOODED by goods from China, and they don't care about making profits off of one unit at a time, instead they are all about volume. Smart move on their part, dumb on ours as we want more more more for less less less :( How many UPS jobs are there for Americans? How many sandwich making jobs are there? We don't make things here anymore, and any innovations discovered/pioneered here immeadiately go off-shore for manufactuing and refinement; cost of labor and little to no environmental laws in Asian countries :( Parts of S. Korea, China, and Taiwan have become toxic wastelands ... better there than here I guess.

Its to the point that the only thing well made in America, are weapons systems ... and its just a matter of time till our tanks, jets, and ships are made in China!

Good luck,

Jonathan
 
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deandome

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Sorry.... 2.8 grams is not good enough for small epoxy batches, by a long shot. The 50 lb version, like I said before, is =/- 5.7 grams.

I've done several dozen tiny 'doses' (mostly for the zillions of fins on my PML matrix), about 3 grams each of A and B. Then I use the same scale for a decent batch of foam for fincans...and a while back, for buckets of West for laminating tubes.



Dean,

Here is a scale, with a LARGE surface (8" x 8") for quart size glasses of liquids, does up to 35 lbs, thats a lot of epoxy, and does +- .1 oz (2.8 grams) sensitivity, black (shows wear and stains less than white/lighter colors), Large LCD Display, delivered for under $20.00.

http://cgi.ebay.com/35-LB-DIGITAL-S...emQQptZLH_DefaultDomain_0?hash=item35a578ac5e

There are more, but I will leave that up to the shopper to find :)

Hope this helps you and others, and I too will stop looking as I have found something to my liking and purchaed it. Won't say, but it is scale on par with the learning things model... just not as big a flat surface, but thats ok because I have a postal shipping scale for those really big items that obscure the LCD; its has a serparate LCD unit on a wire that you can set aside a couple feet away to view the weight.

This is similar to what I have but it is only scalable to 50 lbs:

http://cgi.ebay.com/150-LB-DIGITAL-...emQQptZLH_DefaultDomain_0?hash=item35a5789ace


Sometimes on my small scale with large items, I will place the item on the scale, turn on the unit, wait until it boots up, then lift the item off the scale. The reading will now show but with a '-' in front of the value. Best bet is for anyone who is doing LARGE jobs, is to have a scale where the LCD is on a seperate unit apart from the scale itself.

Point is that with a little patience and work, you can buy just about anything for next to nothing; estate sales, garage sales, buy direct from the OEM, get a resellers license or LLC business name and this will save you paying taxes (local/city/state and don't ask me to educate you on how this process works, you do have to do leg work and research on your own, Dean not you personally just to anyone in general) ... and if you think prices are low now ... 2010 will see even more lay-offs, higher unemployment, and even better deals for those who are patient.

I am just trying to get people to see that they can save a lot of $$$ and get more for their money if they just take the time to look around. Trust me, the scale sold by the learning things can be found elsewhere for the same if not less if you just look. Lerning Things is the only place on planet Earth that has these scales for sale at that or lower price. And there are scales, with more features, and greater flexibility for equal or slightly more money.

BTW, our markets are being FLOODED by goods from China, and they don't care about making profits off of one unit at a time, instead they are all about volume. Smart move on their part, dumb on ours as we want more more more for less less less :( How many UPS jobs are there for Americans? How many sandwich making jobs are there? We don't make things here anymore, and any innovations discovered/pioneered here immeadiately go off-shore for manufactuing and refinement; cost of labor and little to no environmental laws in Asian countries :( Parts of S. Korea, China, and Taiwan have become toxic wastelands ... better there than here I guess.

Its to the point that the only thing well made in America, are weapons systems ... and its just a matter of time till our tanks, jets, and ships are made in China!

Good luck,

Jonathan
 
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JonathanDunbar

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Sorry.... 2.8 grams is not good enough for small epoxy batches, by a long shot. The 50 lb version, like I said before, is =/- 5.7 grams.

I've done several dozen tiny 'doses' (mostly for the zillions of fins on my PML matrix), about 3 grams each of A and B. Then I use the same scale for a decent batch of foam for fincans...and a while back, for buckets of West for laminating tubes.
Sorry ... but then you use the $7.99 scale for small batches. Better weight resolution for small .1 gram and up, and it is VERY portable. Guess it just depends on what your intended use is?

Are you attaching a launch lug or glassing a full sized boat?

What about the other points of the scale I mentioned?

Jonathan
 

Micromeister

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Sorry ... but then you use the $7.99 scale for small batches. Better weight resolution for small .1 gram and up, and it is VERY portable. Guess it just depends on what your intended use is?

Are you attaching a launch lug or glassing a full sized boat?

What about the other points of the scale I mentioned?

Jonathan
I can Ditto Jonathan's post:
I've been using the Scale he mentioned for a couple years now, They are so cheap and accurate i've purchased 3 more for other areas, range boxes and the like. Run on standard AAA batteries rather than 9v or 3v lithiums.
I've been pleased as punch with them, even more then my much higher priced Palm Scale. with a max of 500g that's more then enough for most LPR jobs.
If thats not quit enough they also have table scale for under 20 bucks, but I haven't actually used one of those.

Cen-Tech Pocket 500g Scale-c-sm_2 pic_01-07-07.JPG
 

GregGleason

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Jonathan/John,

Does that Harbor Freight scale have a button to "zero out" the scale once you put a cup on it (for epoxy wt)?

Greg
 

Winston

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RimfireJim

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Again...those are a completely different 'class' of scale.

The table is 2.5" x 2.7"...hardly adequate for a one-quart size plastic mixing container (barely big enough for the Wendys "ketchup cups" I grab for small batches).

A pocket scale is a pocket scale. Show me something with a 6" x 6" or so table...where you can see the display when you have a big container on it, that has 2 kilo capacity and .1 or .5 g accuracy like the kind I'm talking about!! for $20 or less, delivered, then you might have a point.

Flatbed scales like this are also great for the weighing food/ingredients in the kitchen if you don't have a dedicated kitchen scale.
I'm confused, deandome - the specs for the scale you referenced in the link in your original post say "Accuracy is +/- 3.0g.", not .1 or .5g. Where are you getting the .5g figure from?
 

deandome

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It's weird...it's the same #...LER 2428 as the one in the original post... http://www.shopping.com/xPO-Learning...ectronic-Scale AND this one: http://www.potomacproducts.com/Gift...ale-Model-LER2428/765023015706-WD0609050.html

But it doesn't look like EITHER one!! I've scanned/attached the actual box for your perusal.

I'm guessing this is just an educational company (it is) who needs a digital scale in it's lineup, but the actual scale they label 'LER2428' has clearly changed several times.


I'm confused, deandome - the specs for the scale you referenced in the link in your original post say "Accuracy is +/- 3.0g.", not .1 or .5g. Where are you getting the .5g figure from?
Scale Scan.jpg
 

RimfireJim

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I'm guessing this is just an educational company (it is) who needs a digital scale in it's lineup, but the actual scale they label 'LER2428' has clearly changed several times.
I'd agree - their current offering, http://tinyurl.com/yzltdgw, is different yet: 5 kg/11 lb capacity with 1 g resolution, the same as my Taylor kitchen scale.

I'd also be careful to not confuse resolution (increment of the display) with true accuracy. Accuracy is how close it comes to a traceable standard. Technical products should not have a resolution better than their accuracy, as it leads to a false sense of accuracy, but consumer goods often do and will say "accurate" when it really means resolution. That said, for our purposes true accuracy is not all that important - if you're using it to measure equal weights of two part epoxy, you'll probably get the correct proportion even if the actual weight of both is a little off by the same amount.

For comparison, the compact balances we use here at work that are truly accurate to +/-0.1 g for a 2000 g range cost about $300-400. Granted, they have some software features you won't find on low cost scales, but the main cost driver is the guaranteed accuracy.
 

bobkrech

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There are 4 specifications you need to pay attention to when you buy a digital scale.
  1. Capacity: The maximum weight that a scale will measure.
    • Caution: This is a real number. Put 50% higher weight on the pan and you may permanently damage the load cells.
  2. Resolution: The number of digits that a scale will display.
    • Caution: This can be a meaningless number as it has nothing to do with precision or accuracy.
  3. Precision: The variability of the scale readout in reading the same weight over and over again.
    • Caution: This has nothing to do with resolution or accuracy.
  4. Accuracy: The difference between the actual weight and the displayed weight.
    • Caution: This has nothing to do with precision or resolution.
Background: The common digital scales use a load cell for determining weight.

A quality load cell with have a linearity of 0.01% or better. That's a resolution of 1 part in 10,000 or more. That's the minimum linearity you need to measure 1000 grams to an accuracy of +/-0.1 grams. You will only obtain weights to this accuracy if the electronics also have this linearity, and the display has a true resolution of 0.01% or better(accuracy, precision and linearity).

A balance with a capacity of 2000 grams with an accuracy of +/- 0.1 grams costs more than $50, a lot more. The accuracy specs for the for the first balance mentioned in this thread was listed as +/- 3 grams which is 1 part in 667, not +/- 0.1 grams which requires an accuracy of 1 part in 20,000.

A cheap balance, which any $20 balance is, will typically have a load cell/electronics linearity between 0.5% to ~0.05%. (1 part in 200 to 1 part in 2000) What this means is that if it has a capacity of 2000 grams, the best accuracy you can get is +/- 10 gram to +/- 1.0 gram regardless of the number of digits displayed, or the precision (reproducibility) of the displayed reading. The original one quoted as on sale may have the display resolution to read to +/- 0.1 grams and may actually have the precision to repeat the reading to +/- 0.1 grams, but the weight can be off by as much as +/-3 grams according to the published specs.

Fortunately the auto calibration and taring functions help out within a few percent of maximum and minimum weights, so their measurements are probably much better than the rated accuracy limit, but unless you have a good set of calibration weights you can't determine the errors over the entire scale range.

Hobby epoxies are mixed by volume ratios, but commercial epoxies are specified by weight per cents of the epoxy resin (monomer) and hardener (linker), not volume. To obtain maximum performance, you need to get the weight ratios accurate to +/- 1% or 2%.

Bob
 

Scott Evil

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Dean,

This scale sounds perfect for my uses, any left? How do I get a hold of you?

I've sent a couple PM's your way but my "Sent" folder remains at "0". I'm not sure why or if you got them or not. My Inbox works (???)

Scott Broderick
 

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