digital scales help!!!

[joshb]

Will the use of beam scales increase your powder throw time compared to the digital scale and if so, any idea how much longer it takes to load with the beam scales?

After I get my thrower, scale and trickler set up, I can load a shell in about 30 seconds.

 

[Outwest]

I have had really good luck with my RCBS Chargemaster link scale.
I warm it up for 30 minutes and calibrate it every time I use it.

 

[ronemus]

I worked daily with precision analytical balances (I was a research chemist and instrument designer before retiring) that offer the precision and resolution we're looking for here, but those instruments cost thousands to tens of thousands of dollars. To reach a price we're willing to pay, some corners must be cut (vendors won't line up to sell to us below cost). Unfortunately, the instruction manuals accompanying our scales generally aren't very good at spelling out the steps necessary to have them operate to our satisfaction.

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 such as these are commonly bothered by power line noise and transients, but those can be eliminated by using a filtered power strip; I use and recommend a Tripp-Lite Isobar.

Static electricity can easily shift readings by a few grains, so it pays to wipe down all plastic surfaces with an antistatic such as a drier sheet. Don't wear nylon or other static-prone fabrics when working with the scale. A humidifier set to maintain 35% RH will help a lot.

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. An air current that's not even perceptible can easily shift readings at the level of precision we're looking for, but opening and closing a door is a nuisance when you're trying to up the pace. I use a cardboard file box (intended for archival document storage) with one end cut out placed over the scale. The side goes down so the box can be removed for filling with powder, etc. without disturbing the scale. I leave off the top (now facing forward) so I can work my Pact scale/dispenser and A&D fX-120i scale. With the bench closing the bottom and the box closing three sides and the top, air currents have a hard time getting to the scale.

Vibrations are another problem - you don't want to have heavy equipment operating nearby, or foot traffic on a residential floor. You can make a vibration isolator by putting a heavy plate (Steel, stone, concrete, etc. - I use a granite surface plate bought on sale from Enco) on a slab of soft foam, but it may not be effective; really good vibration isolators are expensive.

Strain gage scales (all of them under $600) will drift - it's inherent in the technology, so frequent taring is necessary. Magnetic force restoration is used in electronic lab scales, but typically costs thousands to tens of thousands of dollars. The A&D FX-120i/FX-123 is the entry-level force restoration scale, and a real bargain at ~$600; drift is greatly reduced vs. strain gage scales (not entirely eliminated). If you can afford it I highly recommend buying an FX-123 or a used (now discontinued) F-120i.

 

[Tangent]

Agree with the above. I'd add use check weight each time around the weight range you intend to use. I spent a lot of time in labs and calibration was a big deal, records kept and audited. The caveat is that it's all relative to the accuracy that you require.

 

[64Rambler]

I worked daily with precision analytical balances (I was a research chemist and instrument designer before retiring) that offer the precision and resolution we're looking for here, but those instruments cost thousands to tens of thousands of dollars. To reach a price we're willing to pay, some corners must be cut (vendors won't line up to sell to us below cost). Unfortunately, the instruction manuals accompanying our scales generally aren't very good at spelling out the steps necessary to have them operate to our satisfaction.

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 such as these are commonly bothered by power line noise and transients, but those can be eliminated by using a filtered power strip; I use and recommend a Tripp-Lite Isobar.

Static electricity can easily shift readings by a few grains, so it pays to wipe down all plastic surfaces with an antistatic such as a drier sheet. Don't wear nylon or other static-prone fabrics when working with the scale. A humidifier set to maintain 35% RH will help a lot.

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. An air current that's not even perceptible can easily shift readings at the level of precision we're looking for, but opening and closing a door is a nuisance when you're trying to up the pace. I use a cardboard file box (intended for archival document storage) with one end cut out placed over the scale. The side goes down so the box can be removed for filling with powder, etc. without disturbing the scale. I leave off the top (now facing forward) so I can work my Pact scale/dispenser and A&D fX-120i scale. With the bench closing the bottom and the box closing three sides and the top, air currents have a hard time getting to the scale.

Vibrations are another problem - you don't want to have heavy equipment operating nearby, or foot traffic on a residential floor. You can make a vibration isolator by putting a heavy plate (Steel, stone, concrete, etc. - I use a granite surface plate bought on sale from Enco) on a slab of soft foam, but it may not be effective; really good vibration isolators are expensive.

Strain gage scales (all of them under $600) will drift - it's inherent in the technology, so frequent taring is necessary. Magnetic force restoration is used in electronic lab scales, but typically costs thousands to tens of thousands of dollars. The A&D FX-120i/FX-123 is the entry-level force restoration scale, and a real bargain at ~$600; drift is greatly reduced vs. strain gage scales (not entirely eliminated). If you can afford it I highly recommend buying an FX-123 or a used (now discontinued) F-120i.

^^^^^^^ THIS!!

I'm still a research chemist and the A&D scales are truly a bargain for the performance they give - CE has the best prices I've seen. Most of the balances I work with are easily 10X the cost of the FX120i, but also are 4 and 5 decimal place readouts.
As said by several, make sure it's well warmed up, that the bubble in the level indicator is as centered as you can get it. If it has a grounding lug, use it. Static is probably the #1 enemy of balances - it even effects beam balances! I also run a separate ground wire from the next outlet to the front of the scale by the opening and make sure I touch it every time I pull the cup in and out - this drains the built up static on me and brings me to the same potential as the balance. Don't wear long sleeve shirts while reloading, the friction of the fabric rubbing on itself will generate static. Be careful about leaning on the bench while weighing. If you have a check weight, preferrably at the weight to calibrate the scale, use it! I calibrate every time I start weighing powder if the display is not 100.000g with the calibration weight. I was able to check my weight at work on 2 different 5 place balances and it came in at 100.00012g on both, so I'm pretty confident in the calibration on a 3 place balance.
If you can't get the balance to maintain zero with the pan on and off and back on, there's something wrong in the system somewhere, you just need to find the gremlin that's effecting yours.

 

[Steve Donlon]

I use check weights that I made that match the powder charge I plan to throw for different loads.

 

[Coyotefurharvester]

I've had a RCBS electronic scale running on my bench for 10+ years, given to me by a friend who had it in a box from an estate auction. I use 4 adhesive rubber pads under it and it's level location is marked on the bench. My beam scale location is also marked and it is not moved. These are both 0.1 gr +,- scales, and check weights at and near charge weights (25 ish grs to about 65 grs) can be confirmed with either scale. I load develop for minimal vertical in a 0.4 to hopefully 0.5 gr charge weight range. This results in prairie dog and hunting loads with multiple rifles(mostly factory barrels). I'm not a competitive centerfire shooter, so just don't see the need to upgrade, at a high cost. I rather shoot up more components. My scale power supply runs thru the over head LED shop lights and humidity is kept 45-50%. Wife supplies me with used dryer sheets. I empty powder throwers and keep anti static sheets in the hoppers. My funnels are stacked with sheets in between. The scales usually calibrated with same pan, so I can quickly confirm a charge weight on either scale. Pan is wiped down with a dryer sheet before use. And I keep my scales clean.

 

[Doom]

Like @ronemus I have worked with precision electronic/digital balances and scales, in my case since 1970. Much has changed with the technology but all of the scales regardless of the technology have the same potential problems only to lessor degrees.The advice he gives is priceless. We were taught years ago two methods of weighing. The first is to weigh by difference, you would put the pan on the scale and weigh/record the weight, add whatever you are wanting to weigh and record that weight and use the difference. The other involved taring the scale to make it read zero with something on it. Taring involves either digitally or electronically modifying the the reading and introduces an additional potential error in the process called zero drift and it is independent of calibration drift. Standard practice was to tare the scale before each weighing. As scale electronics improved and digital scales became more prevalent, zero drift became less of a problem but it still exists. The problem with scale zero drift is that is undetectable when less than the scale display resolution. I'm retired and I don't know know what lab procedures are currently saying but performa a zero/tare prior to each weighing is still good practice and minimizes one possible source of error. And tor those who swear by the Fx120i the following is directly from the instruction manual:

"Press the RE-ZERO key before each weighing to eliminate possible errors."

The Fx-120i also has an automatic re-zero capability.

 

[Coyotefurharvester]

Know your pan weight(tare weighing)if you see a zero/pan weight shift. Rezero when stable. I calibrate with the pan, scale at zero with pan on before calibration. As I mentioned I typically cal both scale,beam and electronic, with same pan. Then no dumping, just a pan transfer to confirm target weight. Really very easy to stay in the +,- error range of a scale that is not experiencing environmental influences.

 

[Doom]

^^^^^^^ THIS!!

I'm still a research chemist and the A&D scales are truly a bargain for the performance they give - CE has the best prices I've seen. Most of the balances I work with are easily 10X the cost of the FX120i, but also are 4 and 5 decimal place readouts.
As said by several, make sure it's well warmed up, that the bubble in the level indicator is as centered as you can get it. If it has a grounding lug, use it. Static is probably the #1 enemy of balances - it even effects beam balances! I also run a separate ground wire from the next outlet to the front of the scale by the opening and make sure I touch it every time I pull the cup in and out - this drains the built up static on me and brings me to the same potential as the balance. Don't wear long sleeve shirts while reloading, the friction of the fabric rubbing on itself will generate static. Be careful about leaning on the bench while weighing. If you have a check weight, preferrably at the weight to calibrate the scale, use it! I calibrate every time I start weighing powder if the display is not 100.000g with the calibration weight. I was able to check my weight at work on 2 different 5 place balances and it came in at 100.00012g on both, so I'm pretty confident in the calibration on a 3 place balance.
If you can't get the balance to maintain zero with the pan on and off and back on, there's something wrong in the system somewhere, you just need to find the gremlin that's effecting yours.

A comment on check weights. Weights are available in different accuracy classes and Amazon is not the best place to purchase weights, at least not without an understanding of the different classes and how to use them. Check weights should be of a class that will display to the resolution of the scale. If the scale weighs to 0.01gram then the weight at its tolerance limits should display 0.01 gram. Calibration weights are a different animal. Their tolerances determine the potential bias errors of the scale. But in the case of reloading a bias error is seldom an issue unless multiple scales are used in which case bias error must be considered.

 

[Janeau]

If youre having that much trouble with all 3 scales, it makes me wonder if you're having interference with static, florescent bulbs, or maybe something in the electric cord???

I will believe this is the trouble too..

 

[Liven The Dream]

FX 120 I and make your loading room scale safe .
No Cell Phone, No Fan , LED Light , voltage line regulator and Solid Table and Level .
Good Luck