Bonvoisin Balance Analytique de Laboratoire Haute Précision 300g/0.001g

Commenté aux États-Unis le 5 juillet 2022

The performance is superbly good. Scale is more stable than even its own manual implies. I'm a scientist and regularly use for work 0.001- 0.0001- and even 0.00001- gram reading scales and analytical balances . I've written (non-published) tutorials and essays. Even concrete explanations of buoyancy correction and so on. This scale is a great 0.001-gram-resolution performer. The draft shielding however can very easily torque the surround plate and thereby effect a perturbation to the pan support and thereby obviously perturbing the force that is sensed (and thus the reading displayed). Just use the balance in a place without any draft and you'll be best off. If you DO use the draft shield be very sure that it mechanically is fully secured into ONE way it wants to go. This is not so easily done though. Battery operation works just fine. The accuracy is superb. (TECHNICAL: It seems that the 200-gram weight they perhaps purposely chose to be under 200 grams. Mine was 199.99546 grams. Never mind how I know. The point is that the scale will force this mass to be called 200.000. But this is good. A tidbit extra gain so that if you, like most folks, ignore buoyancy correction for weighing in air, then you'll be a little bit less wrong from the teensy bit higher gain: calling 199.995, 200.000 by the balance. Of course I have no idea what true mass your weight will be. And the value I gave was indeed true mass, not conventional mass value. And that term of art would need a couple of pages of explanation, as does buoyancy correction etc. ALL of which I am skipping.) So then: EXCELLENT performer. Quite accurate. Good resolution of 0.001 grams for its range (500 grams). EASY to use. The manual is well written too. AND the manual has excellent warnings -- even better than other "more serious" laboratory analytical balances give! That was a surprise. Value : Money ratio is outstandingly good.An example application. Frosted Mini Wheats is the ONLY cereal without tons of salt dumped in. (Skipping that topic, but it does amaze me.) So I like it. Then there was Mini Bites version: "half the size". Now is that half by mass (or volume) or in each dimension (which would give one-eight the mass). The scale used on 30 pieces apiece of regular Mini Wheats and Mini Bits Mini Wheats gave virtually exactly a 2.000:1 mass ratio. Half is indeed by mass. (If I measured with a caliper etc... could confirm cube-root-of-two or if not, then the mini bites pack the wheat threads... you get the idea. I'm a precise guy and a metrologist and so on. If I like this balance you definitely will. And there's nothing wrong with it being simple and easy. I would not use the draft shield if at all possible. And I would get the 200-gram weight provided analyzed for true mass. Best is indeed if it is a bit under 200 grams for TRUE mass. That way the teensy extra gain will give the displayed values being even closer to true mass even if you don't do buoyancy correction for weighing in air.For things like my cereal mini bites vs. full-size, this scale is a real pleasure. And perfect range and display resolution. Great for pills counting too. Many other uses. And very little money.

Commenté aux États-Unis le 4 avril 2022

Comes well packed in a foam lined box inside another foam lined box. 9V battery is required and a little hard to get fitted in the battery compartment. The balance measurement is steady once air currents and hands are removed from influencing the pan. The tare button once pressed stops the balance drift upwards after turning it on. It takes 5 min to stabilize. Excellent weighing technique is required to not cause the tare “zero” to change requiring a re-taring. I find weighing a three times reveals the balance will give the same number and return to zero if the pan is not bumped hard or the pan enclosure is not touched. I’ve left the right side panel of the enclosure off and the roof on with the roof’s hole closed. I can add and remove items without touching anything except the item to the pan using tweezers. This technique yields accurate repeatable results. I do have to use the tare more frequently than I’d like. The pan enclosure can too easily move which will always affect the tared zero point. I think that is a design flaw. I’ve put around 1 kg of weight evenly distributed on the roof of the pan to stabilize and secure it to the balance. That works well for me. Currently I am weighing air rifle pellets which average 15.89 grains. Weights vary only 0.01 - 0.02 grains if I follow careful weighing technique. Similarly, milligrams vary by 1 - 2 mg. For the price the balance is effective for my use. I highly recommend getting one or two weights from Troemner at the certification level required for your needs. A truly accurate weight set for this balance will cost several thousand dollars. A single weight will cost hundreds. I needed accurate relative weights, not absolute weights, so I elected for a cheap sub hundred dollar weight set with no certification.Update April 29, 2022: have found balance really needs about 5 min to warm up before the tare is truly stable. Recalibrating occasionally has been helpful too. Balance is still excellent for my purposes.Update July 9, 2022: The power adapter is the best way to power the balance. A 9V battery works for just a few hours. I found putting stick on rubber feet on the four corners of the floor of plastic enclosure fixed the problem either the enclosure affecting the tare. I no longer need to load the roof of the enclosure with weight. I turn on the balance, let warm up for 5 min, use the 100g calibration weight to settle the mechanism, remove and tare the pan. Then I’m ready to go. Awesome balance for the price.

Commenté aux États-Unis le 7 août 2023

I'm a reloader.I acquired the Bonvoisin Lab Analytical Balance to be able to check and control my loads. At the same time, I acquired a Calibration Weight Set Calibration Weight Class F1, and have checked the precision, which is good.The Bonvoisin Lab Analytical Balance is equipped with a 200-gram calibration weight and has good precision when the same weight is repeated several times.A nice feature is the settings for calibration, which can be set as a single-point calibration to be used with the provided 200g calibration weight or as a multi-point calibration, which require a 500g, 400g, 300g, 200g and 100g calibration weight.I find the single-point calibration provides sufficient precision.The Bonvoisin Lab Analytical Balance is also equipped with a shield for the balance pan itself, but in my case, I don't need the shield as my balance is not subject to drag.The scale has more settings for sensitivity and the factory settings responds to a change of 2mg, which is sufficient for my use, but a higher sensitivity setting is possible which may require use of a shield.Another reason I chose the Bonvoisin Lab Analytical Balance is that it has many different conversion functions and a handy counting function.The scale has a good finish and offers good value for money - can be recommended.

Commenté au Canada le 16 octobre 2023

Received defective product and company promptly shipped replacement unit.

Commenté aux États-Unis le 14 septembre 2022

I have this scale which should be +/- ~0.02grn, a ~$30 pocket scale that is +/- 0.02grn, and my RCBS scale that is +/- 0.1grn. The RCBS scale (designed specifically for my use with powder charge measurement) and the $30 scale are both accurate and repeatable. I frequently check with a nice set of calibrated weights. I have found this Bonvoisin scale to be extremely accurate for measuring single or multiple solid objects like boolits and brass cases. It did have a little drift weighing out these items but only 0.08grn (0.05%) at most and was less after 30min warmup, calibration, zero, then start. It reads my calibrated weights perfectly every time... However, it does not work for trickling up powder (each powder granual is ~0.02grn to ~0.03grn). This was the main reason I purchased this scale, but it does not do well with very small incremental changes... After communicating with the seller/manufacturer, this does seem to be an issue with this model. They stated that they plan to make clarifications about this in their item description/information. They were very open, honest, respectful, and understanding. As powder trickling was the main reason I purchased this item, they were kind enough to offer me a full refund... Conclusions: The scale is really great for solid objects of more than a about 1grn each. It is not suitable for trickling up with individual granuals of powder. The company stated that liquid trickling can be an issue as well though that is not something I have needed to test. In short, just be mindful of your needs and this products limitations.