I bought new bench scales (plus, discount code for Australian buyers) - Page 1
Forum section: electronics / general

author: Halcyon
author_rank: Unknown
timestamp: July 15, 2021, 07:10:12 am
content: Because I justknowsomeone is going to have a sook, I'd like to start off by saying that this post is completely my own opinion and I chose to write this voluntarily. It's not sponsored in any way and I didn't receive any additional discounts or benefits.I bought this item myself from Wedderburn's online store and wanted to share it with others.So, I've been hunting around for a decent set of accurate and reliable scales for use at home in the kitchen. Over the years I've used several "consumer grade" scales and my last one (which was just a cheapy from Ikea) ended up breaking after just 6 months. I was sick of wasting money on cheap crap.I'd heard ofWedderburnbefore as they've been around in Australia since the 1890's. They make all kinds of industrial and commercial scales (among other things) and you'll see them everywhere in the food retail and manufacturing industry.Anyway, I ended up settling on the WS2014K model, which measures up to 4 kilograms in 0.2 gram graduations. Since it's unlikely I'll be weighing anything in the kitchen exceeding 4kg, it was a good combination of weighing capacity and accuracy. I also wanted something that was accurate down in the single and double-digit grams. This one is just a basic scale with the expected functions, but also has a counting function which is quite nifty (not sure what I'd use it for while cooking, but it's there). The construction feels nice and sturdy and the platform is generously sized. This is powered by either the included AC adapter or C-size batteries (other models have a rechargeable battery, but that wasn't important to me).What I really like about it:The backlight is really nice and the glow is evenly spread across the entire display. The LCD itself is very crisp with excellent contrast.The ability to program various settings which are retained even after all power/batteries are removed. These settings are:Backlight:On / Off / Auto (Auto keeps the backlight off until you start weighing)Auto Power-off:Disabled / 5 min. / 10 min. / 15 minMy last set of scales had a ridiculously short auto power-off timeout (something like 60 or 90 seconds) which pissed me off so the ability to program these scales to a more respectable setting is brilliant.It also came calibrated from the date of my order.The tactile dome switches are firm with a decisive and satisfying snap.The stainless steel platform is removable for cleaning.The response and settling time is really quick on measurement. I'm not sure what the "refresh" rate is, but it's many times per second. These are some fast scales!Things I would change:The black rubber feet leave faint marks on my white stone kitchen bench top. Silicone pads would have been nicer.An option to disable the keypress beep would have also been nice. I can't see a way of disabling it without opening the unit.The ability to adjust the backlight brightness would have also been a nice touch, particularly if you're running on batteries. Wedderburn claim about 160 hours of runtime with the backlight on, which is still plenty for my application.Ordering:You can purchase this and other models from Wedderburn directly at:https://www.wedderburnonline.com.auAt the time of posting they are currently offering free shipping within Australia. In addition, the person I dealt with from Wedderburn was also kind enough to offer a discount code to share.You can get 10% off your order for the next 35 days by using the discount code39-0052-912571.

author: TerraHertz
author_rank: Super Contributor
timestamp: July 15, 2021, 08:26:15 am
content: Coincidence, I bought a bench scale recently too. Except I'm a cheap arse, and so bought one from Aliexpress.https://www.aliexpress.com/item/4000092922313.htmlThey have a range of models with various full scale vs precisions.I bought a 6KG0.1G Max 6Kg/0.1g resolution. I'd have bought a lower max limit, finer resolution model, except there are some 5Kg metal things I wanted to check for exact weight.Total was AU$ 156.81 (incl shipping & GST)This one does proper counting of quantities. For which you have to have a numeric entry pad, so for very small things you can put on some number of them (eg 10 or 23, whatever), tell the scales how many there are so it can calculate average unit weight, then dump a bunch more on the tray.It has a compartment and leads for a biggish lead acid battery (with internal charger) but doesn't come with the battery. Runs off mains.Amusingly it has no facility to measure in lb/oz. I rather approve!

author: Halcyon
author_rank: Unknown
timestamp: July 15, 2021, 09:22:21 am
content: Quote from: TerraHertz on July 15, 2021, 08:26:15 amI'm with you on this! This seems to be a legacy unit just kept in for good measure (pardon the pun) that no one that I've known in my lifetime has ever used.The count feature on mine works the same way however it's limited to initial sample sizes of 10, 20, 50 or 100. Still, not bad for a basic scale.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: July 15, 2021, 09:37:06 am
content: Quote from: Halcyon on July 15, 2021, 09:22:21 amNo good for measuring 12 ounces of beer either. Just runs all over the bench.

author: jfiresto
author_rank: Frequent Contributor
timestamp: July 15, 2021, 09:50:09 am
content: Tare the glass and then fill it works for me.I was curious if either scale can be user calibrated. The product info would usually mention that, or better still, specify the suggested calibration weight(s) – which set a limit to the scale's accuracy.I ask because I had to replace a Swiss-made kitchen scale after its strain gauge sensor had drifted about +0.6% over 20 years.

author: TerraHertz
author_rank: Super Contributor
timestamp: July 15, 2021, 10:50:49 am
content: The Chinese one (but wait, they are probably BOTH made in China) likely does have some adjustement internally, since the case has a couple of 'wire and pressed lead' seals to prevent it being opened. Which I don't want to disturb. Making it kind of unique in my toolset, as the only thing I can't open for curiosity.

author: peteru
author_rank: Regular Contributor
timestamp: July 15, 2021, 11:04:27 am
content: I was contemplating scales for brewing beer. These need to be able to weigh out 4-7kg of grain (where the resolution is not all that important) and also hops in the 10-200g range to the nearest gram. For salt additions, I have scales that are good for 200g, +/- 0.1gBoth of the above look like contenders, although I might have to split the grain quantities for larger batches.

author: Ian.M
author_rank: Super Contributor
timestamp: July 15, 2021, 11:32:17 am
content: Quote from: Halcyon on July 15, 2021, 09:22:21 amThat depends on how often you cook from recipes in old cookbooks. Its easier to make a serious mistake if you have to do units conversion 'on the fly'!Quote from: peteru on July 15, 2021, 11:04:27 amRequiring one set of scales to have resolution five orders of magnitude finer than their FSD is going to limit you to rather expensive laboratory grade scales.Your application cries out for two sets of scales, one heavy duty and waterproof (so you can also use it for measuring water volumes) with 5g resolution with a corded or wireless remote display, and the other small and sensitive for precision weighing under 200g.IMHO use your existing salt scales for weighing your hops, even if you have to weigh them in two batches when brewing large batches of heavily hopped beers, which will make it much easier to find suitable heavy duty scales

author: peteru
author_rank: Regular Contributor
timestamp: July 15, 2021, 12:12:52 pm
content: I'm not looking for one set of scales to do everything. I am happy to continue using the precision scales with 0.1g resolution for the salt additions.What I would like is a second set of scales that has 1g resolution somewhere up to about 500g or 1kg and a maximum range to about 5-10kg with coarser resolution. That ought to be doable.

author: HighVoltage
author_rank: Super Contributor
timestamp: July 15, 2021, 12:20:45 pm
content: I found a really nice Mettler Toledo scale on ebay a few months ago. They are usually very expensive but I got a really good price.It has so much resolution, it can detect the weight of a pencil line on a paper. Really impressive to see this for the first time.

author: Ian.M
author_rank: Super Contributor
timestamp: July 15, 2021, 12:28:54 pm
content: Quote from: peteru on July 15, 2021, 12:12:52 pmNope, not economically. The max FSD range and accuracy is constrained by the load cells used. There is therefore little point in switching ranges as displays and 16 bit ADCs suitable for 4 1/2 digit resolution are now dirt cheap, and to switch ranges meaningfully either requires two sets of load cells in cascade with precision mechanical stops to transfer the load to the heavy duty ones when the low range ones are slightly over their nominal FSD, or moveable pivot points for the lever(s) supporting the platform.Quote from: HighVoltage on July 15, 2021, 12:20:45 pmUnless you get very lucky on Ebay, it will almost certainly be cheaper to get two new scales, one for mid-range and the other for heavy weighing than one that can do both jobs. This also has the advantage that you can leave the heavy scales under your mash tun (and possibly under its heater if its a gas or electric ring with a highly flexible cord or hose supported at a fixed point near the scales) for the duration, so you don't break your back humping the tun onto and off of the scales, while still having the mid-range and precision scales conveniently placed on your counter for weighing the other ingredients.

author: jfiresto
author_rank: Frequent Contributor
timestamp: July 15, 2021, 12:43:31 pm
content: Quote from: HighVoltage on July 15, 2021, 12:20:45 pmI have been meaning to get an analytical balance to better measure small objects. That one looks nice and is old enough that it does not auto-recalibrate when you open a window.To reduce temperature changes and air currents, our friendly, local office of weights and measures (Eichamt) has their balances in a small, closed, lowered-ceiling room inside a bigger room.

author: austfox
author_rank: Regular Contributor
timestamp: July 15, 2021, 02:05:05 pm
content: On a side note, Wedderburn were in a lovely grand old building on Paramatta Rd at Summer Hill (in Sydney) for many decades. Unfortunately that building has long gone. The new building on that site now houses Wagner Electronic Services (WES), suppliers of electronic components with a particular emphasis on the service technician and installers (alarm, audio/visual etc).I haven’t used a Wedderburn for years, but I remember the one we had at the shop back in the 80’s, complete with nixie tube displays. It was huge by today’s standards, but just kept working!

author: peteru
author_rank: Regular Contributor
timestamp: July 15, 2021, 02:10:51 pm
content: Wedderburn scales and slicers seem to be in every Woolworths store I've been to. At least the deli, butcher and seafood departments. Local butcher and fruit-n-veg shop also have them. One would assume that it's gear that just works and when it doesn't, it's backed by solid service.

author: HighVoltage
author_rank: Super Contributor
timestamp: July 15, 2021, 02:25:58 pm
content: Quote from: Ian.M on July 15, 2021, 12:28:54 pmActually, you can get very lucky on ebay from time to time. I bought a few other Mettler Toledo scales for the different ranges and they are just working perfectly.However, I must admit that I bought one Mettler scale that was only good as a parts supplier.After spending quiet some time with scales in the last weeks, I am more and more intrigued by high quality scales.

author: HighVoltage
author_rank: Super Contributor
timestamp: July 15, 2021, 02:30:09 pm
content: Quote from: jfiresto on July 15, 2021, 12:43:31 pmInterestingly, temperature does not have such large influence as air current.But, what surprised me is the large influence by static electricity.But be careful, once you open the door to precision scaling, you need very accurate calibration weights and they can cost more than the scale.

author: deadlylover
author_rank: Frequent Contributor
timestamp: July 15, 2021, 04:40:37 pm
content: Where was that Wedderburn scale made if you don't mind me asking?Bestie is an analytical chemist and he recommends A&D or Sartorius....not that the advice would be of much use for the home hobbyist. Maybe if we get lucky on eBay?In the kitchen I have an A&D SK-2000 (made in Korea), it's a basic model only capable of 2000g x 1g but that's enough for general cooking. I got it for AUD 88 which is a bloody steal from their surplus store on theAussie website, but it looks like they don't have any scales on clearance anymore. (but maybe someone in the future will get lucky!)

author: Halcyon
author_rank: Unknown
timestamp: July 15, 2021, 10:54:59 pm
content: Quote from: jfiresto on July 15, 2021, 09:50:09 amThere is an "offset" setting on my scale which seems to have been pre-programmed. I'm guessing this is the calibration? I'm not going to mess with it. There is also an error code in the manual that refers to "incorrect calibration weights" but then just refers the user back to the manufacturer. So whilst the manual doesn't tell you how to do it, it appears you can do it.I might reach out and see if they are willing to share the calibration procedure with me.Quote from: peteru on July 15, 2021, 11:04:27 amWedderburn have other scales in the same WS201 model range. There is also a WS20110K (10kg/0.5g) and WS20120K (20kg/1g). There also other models that are IP68 rated such as the WS20215K (15kg/1g).Quote from: HighVoltage on July 15, 2021, 12:20:45 pmI did look at MT as well. They make some really nice gear. But yes, quite expensive. Even the Wedderburn ones started to approach the limit of what I wanted to spend on a set of kitchen scales that I might use a few times a week, but they should last many years.Quote from: peteru on July 15, 2021, 02:10:51 pmI have to say, the service from them during the sales process was absolutely top notch. The person I dealt with got back to me via email within 30 minutes or less and was even responding after hours. I'd like to think that their after-sales service is just as good. To be honest, I was half-expecting them not to even bother with me as an end-user wanting a low-end set of scales, but that turned out not to be the case at all.Quote from: deadlylover on July 15, 2021, 04:40:37 pmChina, like everything else. I don't know if they still manufacture any of their products in Australia (maybe some of the higher-end units?). All the service, calibration, repairs etc... are done here in Sydney. They have a huge warehouse and office complex in Ingleburn. They have labs in Sydney. Brisbane, Melbourne and Perth which are all NATA accredited. This is the link to the Sydney (Ingleburn) site accreditation:https://www.nata.com.au/entity_scope/?AccNo=5486&q1=487&str=&&AccNo=5486

author: deadlylover
author_rank: Frequent Contributor
timestamp: July 16, 2021, 02:45:02 am
content: Quote from: Halcyon on July 15, 2021, 10:54:59 pmIs the offset value similar to the value of gravity? It could be the adjustment for gravity compensation for when you move location but don't have access to calibration weights.The manual for my A&D SK-2000has a world map and a graph for gravity compensation, which is hilarious for an entry-level scale.Thanks for checking where it's made, it doesn't matter much in the grand scheme of things but it would have been icing on the cake.

author: Halcyon
author_rank: Unknown
timestamp: July 16, 2021, 03:43:19 am
content: Quote from: deadlylover on July 16, 2021, 02:45:02 amI'm not too sure. The manual is very basic (more like a quick start guide) and it doesn't mention what "offset" does. If I go into it, it shows 130350 on the display but the last two digits bounce around a little bit, so not quite sure what that's about. It's obviously measuring or getting live data from something. I'm just assuming it's something the average end-user shouldn't be playing around with. No doubt there is a separate technical guide.

author: HighVoltage
author_rank: Super Contributor
timestamp: July 16, 2021, 09:13:46 am
content: Quote from: Halcyon on July 15, 2021, 10:54:59 pmMT also has some not so expensive scales.I bought a few of theARIVA-MINi-Smodels.They go up to 6 kg at 1 g resolution.But with a "secret" menu found in the service book, one can turn on the 0.1g resolution and can weight up to 10 kg.

author: Halcyon
author_rank: Unknown
timestamp: July 16, 2021, 09:55:57 am
content: Quote from: HighVoltage on July 16, 2021, 09:13:46 amMy understanding is that it's a limitation with the load cells and the graduations are just one aspect of the "accuracy". The way it has been explained to me is that a worst-case, accuracy is about 20 times the graduation. So if you have a scale capable of 0.1g graduations, the maximum error you can expect (on a calibrated scale) is +/- 2 grams. I'm sure some other people here can explain the science/technology behind it.If you're able to "tweak" the settings, it might just be that the chassis/firmware is designed for a number of different models (as is the scales I bought) however the load cells are physically different. You might actually be throwing your scales more out of spec by overloading them and potentially damaging the load cells.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 16, 2021, 10:17:19 am
content: I have two types of scale: 1) Ohaus Scout (20 years old, 10 mg resolution) ; and 2) Various scales to 2 kg with 1-g resolution.The latter are for cooking postage calculation and so forth. I use the former for any other purpose, such a mixing adhesives. If I could only have one, it would be the Ohaus. A good wooden spoon can be used for estimating weights when cooking.Just FYI, buying the latter was never a problem. They are even available at Harbor Freight. The former involved dealing with the DEA to insure I was not using it for an illegal purpose. I was buying from a well known scientific distributor. That may not be a problem with local/individual sales. Or maybe, resolutions of <=10 mg have become so common that the DEA (USA) has just given up.

author: jfiresto
author_rank: Frequent Contributor
timestamp: July 16, 2021, 06:10:14 pm
content: Quote from: Halcyon on July 16, 2021, 09:55:57 amIf I received a scale with up to a 20 count error, I would return it. I would want the reproducibility and linearity to be an order of magnitude better, or why distract me with the last digit?

author: Halcyon
author_rank: Unknown
timestamp: July 17, 2021, 02:45:50 am
content: Quote from: jfiresto on July 16, 2021, 06:10:14 pmApparently that's the way it is with these types of scales. Accuracy isn't necessarily linear. It's not a fault, it's a characteristic of how the weight is measured with load cells.And I did say "worst case". With a decent set of scales, the error is likely to be far less. Cheap scales, well, who bloody knows.

author: jfiresto
author_rank: Frequent Contributor
timestamp: July 17, 2021, 06:28:35 am
content: Here are someschoolandentry-level labbalances that suggest the accuracy you can expect from a strain gauge load cell, with careful design and Chinese manufacture. Both do significantly better than 20 counts, worst case!EDIT: I have an EMB 200-2, which is not bad, but I find a little too frugal with its just two buttons. I wish it had one more to skip the button dance you must do to start a calibration.

author: Halcyon
author_rank: Unknown
timestamp: July 17, 2021, 09:13:06 am
content: Well as I said, this is why I bought a decent set of scales this time. My previous ones have been crap and probably terribly inaccurate.

author: HighVoltage
author_rank: Super Contributor
timestamp: July 17, 2021, 09:53:06 am
content: Quote from: Halcyon on July 16, 2021, 09:55:57 amBased on my limited experience with Mettler Toledo scales, the error is much smaller.The linearity is just amazing and with the calibration weights I have and the resolution the scales offer, I can not detect a deviation from perfect mx+b function.The calibration for these MT scales is done at 0 weight and full scale weight.But one needs to be careful, not to move the scale after calibration.You can easily detect a difference in gravitational pull, if you move a calibrated scale one floor up in the house.Also, it is important to think about air weight displacement by the part that is being measured.Look for "Balance Corrections for Buoyancy" see attached pdf

author: Halcyon
author_rank: Unknown
timestamp: July 18, 2021, 12:43:36 am
content: Quote from: HighVoltage on July 17, 2021, 09:53:06 amAs they should be. Like anything, you get what you pay for. I don't need lab-quality accuracy in the kitchen, but if I'm measuring a few grams, I want to be confident that the reading is accurate.That being said, I wonder how much my calibration is off (if at all). They were calibrated at about 30 metres ASL, I'm at 800+ metres ASL.

author: HighVoltage
author_rank: Super Contributor
timestamp: July 18, 2021, 10:17:35 am
content: Quote from: Halcyon on July 18, 2021, 12:43:36 amFor a "normal" scale, the error of +800m will not be detected.At +800m you get around 0.01% deviation from your calibrated value.A 1.0 gram weight would theoretically show 0.999748 gram at +800mBut theBuoyancyeffect is much larger than I had thought.For instance:Steel has a density of 7850 kg/m3A 2 kg weight 2*1000/7850 = 0.254777 liter of volume1 m3 air is about 1.3 kg1 liter of air is therefore 0.0013 kg0.25 liter of air is 0.254*1.3/1000 = 0.0003302 kg = 0.3302 gramTherefore a 2 kg weight is about 0.3302 gram heavier in vacuumThis is a difference of 0.0001651 or 0.01651 % or 165 ppmAnd it surprised me that it is so much.