scale rant

[JustinP]

Rant ON

After years of struggling with electronic scales, I decided to go upmarket and splash out on an Acculab VIC-123 set. Fantastic, I hear people say...

Well, after setting it up dead level, adjusting it for 'very unstable' conditions, on a rock solid table in a room devoid of any electonic interference and running it through a voltage regulated/conditioned line, calibrating it on each setup and letting it warm up for an hour, the bloody thing still drifts, each time I use it. I still have to zero it frequently after putting the weighing pan back on the platen and for reasons unknown, on occasion it goes marching off in it's own direction. For example, I have just, in a fit of frustration, restarted the whole process to make sure I'd done everything exactly right. I then left the room for ten minutes and have just ducked back in to check it .... 0.4gr out of zero and climbing. WTF???????

I tell you, I'm about to bin the whole bloody electronic scale business and go back to a balance beam. It turns out they're probably faster and more accurate than what I'm currently going through...

Rant OFF

Justin

 

[BillK]

justin- I use a mettler scale and have no problems at all with its function. I do however let it warm up a couple of hours and I bounce the load center up and down a bit with my finger to help warm it up. Over several hours of weighing charges it generally stays within one hundredth of a grain. I also make standards of each charge that I want to shoot. This way I can tell if the load center is ending up where I want it. I don't really care for the zero as long as the standard gives me the same number every time!!!!!!!!!

 

[memilanuk]

Justin,

Join the club. I hate to say it, but I feel just a wee bit better knowing I'm not the only one waxing ecstatic about these things. When they work, they work great. It's just getting them to settle down and stop being such a PITA takes some doing. I'd suggest turning it on and *leaving* it on, as the drifting after power-up can take *hours* to settle out.

I was on the phone w/ Sinclair International ordering some stuff today and spoke w/ Phil,their 'go-to' guy on these scales) about the problems I've had. He was somewhat at a loss as I've done pretty much everything a person is supposed to do with the scale, as have you. He had two suggestions to try, and if those don't work, I'll be calling the engineer @ Sartorius again.

1) Sometimes the unit supposedly settles down better if you 'exercise' the load cells. Gently,***GENTLY***) push down on the platen until the screen reads something like 'OL' or 'UL',overload), then release. Do that a couple times. Something about we are running this thing right at the bottom end of its range, and it needs worked a little once in a while. Dunno how well it'll work, but we'll see.

2) Find a cardboard box or plastic tub that fits over the unit, and make appropriate cutouts for reaching in, trickling, etc. Should do a better job of shielding the unit from air currents, as you can't,at least I can't) close the lid that comes with them w/ the pan on the platen.

Hope this helps you out some. I'm going to give these last two a try, if no improvement I'll be calling Sartorius next week...

Monte

 

[JustinP]

Guys

Thanks to your reasoned replies to my venting of frustration.

I'll try the notion of 'exercising' the platen - but beyond that, I don't know if there's much else I can do. Monte, I hear what you're saying regarding shrouding the scale work area to keep out drafts but I'm thinking that there is a point of diminishing returns in terms of time and effort. At what point do you just decide enough is enough and move on. I find myself spending a disproportionate amount of time on trying to get this thing to work to spec.

As it stands, I had it on for over 12hrs yesterday, after letting it warm up for 2-3 hours. At no point would it hold a zero with the empty pan on the platen for more than a couple of throws - and at other times, it will just inexplicably drift. I watched incredulously as it proceeded to drift from 'just zero-ed' to 0.42gr. Did it return to zero? Nope.

I'll be interested to hear if anyone else has had similar problems. Monte, it'd be great to hear how you go with yours in the immediate future.

I'm off to put an icepack on my head. My reloading bench has a forehead shaped indentation in it...

 

[memilanuk]

Justin...

I feel for ya man

I'm off to work on 'finishing' my bench top... putting a 1/8" tempered hardboard skin on it over the triple thickness of 3/4" plywood, plus add some oak edging. My biggest concern? I have to unplug that <bleep>ing scale, which means it will have to go the power-up/warm-up cycle again. Ah, well, guess I'll just leave it on overnight.

Monte

 

[mikecr]

My Acculab does the same..
No solution

Wasted money till I find an answer. Then it'll rock

 

[JustinP]

Mike

Until I find/hear of a solution - mine may as well BE a rock

 

[ronemus]

It is necessary to isolate the scale from drafts and vibrations. Laboratory scales with this sort of resolution generally have a housing around the pan with sliding doors for access and vibration isolators in the feet. Those scales cost thousands of dollars, and some features must be cut to reach a price we're willing to pay. Unfortunately, the instruction manuals accompanying our scales generally aren't very good at spelling out the steps necessary to have then operate to our satisfaction.

A small draft,one you can barely feel) can easily shift the reading a few tenths of a grain, so some sort of enclosure is needed. I use a cardboard file box with one end cut out, so 3 sides and the top remain, and that's good enough for 0.1 gr,6 mg) stability; however, that may not be sufficient for 0.01 gr.

For stable zeros it's necessary to warm up for at least a few hours,they're generally left on continuously to avoid drift) and keep the room temperature fairly constant,within a few degrees).

Inexpensive scales are also susceptible to electrical noise, either riding the power line or through the air. Power line noise can be eliminated with a good filtered power strip,I recommend a Tripp-Lite Iso-Bar), not just a surge suppressor. Cordless and cell phones, fluorescent lights, wireless computer networks, baby monitors, etc. can cause problems at short range, so they should be kept away from the scale as much as possible.

 

[JustinP]

I'm going to try:

1. Leaving the scale on for a few days
2. Shrouding it with a cover
3. Minimising,further) any potential electrical interference
4. Exercising the platen by gently pushing it down, then releasing during the 'warm-up'

...and checking all the loads thrown against my beam balance scale

If it keeps drifting after all that, it's getting the heave-ho and I'll rely on the balance scale

An engineer friend of mine has never used electronic scales or chronographs of the non-laboratory grade type, as he reasons that the electronics are simply not up to scratch. He only weighs charges with a beam balance...lesson to be learned there, I think. My effort to cut down time at the bench through use of these scales, which are supposed to be of relatively good quality has backfired pretty badly. I spend more time trying to ensure accuracy negating variables are removed and that the scales are accurate, than I do pouring powder into cases. It's not only an incorrect expenditure of time but is also stressful and bites into confidence in the outcome...

 

[Kevin_Duckworth]

I think sometimes we don't realise the environment that scales require.

I worked as an analytical chemist for 20 years. Our scales lived in a temperature controlled room, were never turned off for months on end, sat on concrete benches with massive concrete bases set into the ground and with anti-vibration mounts, had screening from any drafts, were regularly checked against traceable masses, and had a regular service schedule.

I suspect relative to this some loading rooms leave a little to be desired. So I understand why people go back to beam balances.

Having said this my Acculab works well. I turn it on at least the night before I want to use it,often leave it running for days), and mount it on a concrete slab sitting on concrete blocks on a concrete floor,all sourced from local garden center) away from drafts.

 

[Bob3700]

Justin,

Had the same scale as you. I had the exact same experience with it. Drifting zero's after I left it on for a week!

Reset all the settings per the engineers and still no good.

Finally sent it back and they replaced it with another unit. The second unit is definately much better. Once it is warmed up,I turn it on several hours before I begin to reload) it is very stable and repeatable.

I would tell the manufacturer that I wanted a replacement, no use in messing around with a unit that is not working correctly.

RGDS

Bob

 

[memilanuk]

Well, I've been using the heck out of my AccuLab the last 4-5 days... loaded about 500rds of match ammo... for the *most* part it's been behaving itself. Every once in a while it'd hiccup and be ~0.14-0.16gr off just out of the middle of no where, from one charge to the next. Usually a simple rezero, and excercise the platen just to be sure, took care of things. Frequent checks w/ a set of RCBS Deluxe Check Weights helped maintain confidence in the results, up til now.

Right now, though, I'm *still* waiting for the damn thing to settle down. Sat down to weigh some more charges, same as yesterday, same as the day before, and the day before that... the scale has been on for about a month now, no mysterious breezes developed in my basement shop in the last 24 hours, etc. Got about 24 charges in, and it went snakey on me again. Took off 'running'. Not 'drifting','running'. Threw a charge into the pan, it was a bit high. Went to take a few kernels out and re-weighed... it weighed more than before. Sat and watched it start marching up... 46.56... 46.58... 46.60... kept on going. Threw the charge back, zeroed the pan and put the check weights in it,these weigh 46.52 +/-0.02 on this scale)... 46.72... 46.76... 46.80. Went to lunch, came back. Appeared to have settled down a full 1.5 grains off. So... tried re-zeroing, exercising the platen, etc. etc. yada yada. Started weighing charges... and it started 'running' again. It's now 0.52gr off again within 15 minutes.

Sorry, this isn't some 'stray breeze' as others have attempted to suggest. Time to call the factory.

Monte

Edited to add... in the time it took me to type this,and I'm not a terribly slow typist either)... it's now up to 4.38 grains off. Nice. Surprisingly enough, it seems to pass the Calibration check just fine... even though it's 0.08 to 0.10gr off of zero by the end of the cal check. Three times in a row.

 

[Asa_Yam]

Monte,

The most drift in 24 hours on my balance was 0.12 grains, and the most during one loading session was 0.04-0.06 grains. Then again, there are big differences between a sub-$300 balance and an A&D GF-200.

 

[memilanuk]

Asa,

I've got a call in to the engineer... we'll see if he has any revelations as to WTF is going on here.

I'm about ready to say heck w/ it and call it a good idea gone bad,in my case) and fork over the $$$ for a *good* scale.

Should have drawn the line in the sand with this thing long ago.

Monte

 

[JustinP]

Bob

I'm in Australia and bought my Acculab scale through Sinclair's. I'm thinking that getting a replacement may end up being all too hard. I might try contacting Sinclair to see if they'll act for me, since they were the selling agent.

Monte

Hear what you're saying about the 'run' versus the 'drift'. Mine does the same thing - just goes off with an steadily increasing charge reading, although mine doesn't do it as badly as yours, from the sound of it.

In the meantime, back to the balance scale...

Justin

 

[shcal]

I had all the same problems as all of you hear. My soluiton was to bring back the goo old balance beam scale, lot quicker and I check it with a weight every so often. Low tech still works great.

 

[jtm]

JustinP Im not having your probs.yet AC2 unit is not giving any power long to short go to
kim.irving@sartorius.com
he seem intrested any way other wise sartorius usa told me id have to go thru sinclairs it may be worth atry
good luck jim

 

[JustinP]

Jim

I'll send the guy an e-mail and see what comes of it. Thanks very much for the steer.

Justin

 

[jtm]

sorry justin i forgot the au on the end

 

[BillK]

You guys are too worried about the zero of the scale you should try to make a standard of your charge weight and measure it. I do this and measure it in between charges to make sure the scale hits the number I want. The standard is made off of my beam scale. It is used as a reference to make sure the scale hits the same number where it really counts with the charge on the scale!!!!! If I am shooting 53.4 grains of powder my standard weighs 53.4grains. I usually use a washer or a screw that will slightly overweight and file a little off at a time to get it to where it needs to be!!!! The best I can measure on my scale is .02grains resolution and that is because re22 is .02grains per kernel. So with that said I will start by putting my standard on the scale in the pan. I will write down the number I get. Now every roughed out charge that is put in that pan needs to be brought to the same number I got with the standard. As long as that scale reads the same number with that standard in the pan you are ok. You can follow every charge with the standard to make sure that the scale is tracking ok!!!!
You all don't need to duplicate the zero of the scale to tight tolerances. You need to duplicate the charge weight to tight tolerances. Think about it and try it. If the scale won't repeat your standards weight then it is time to worry!!!!!