Why is my RCBS scale tipping in the presence of this plastic? Head scratcher!


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GJgo
January 28, 2012, 12:37 AM
This is a weird one, need some help 'splainin. I use a RCBS 5-0-5 scale. The zero tends to float 0.1 grain from day to day, so I always re-zero, no big deal.

Recently I picked up one of those media tumblers from Cabela's that seperates the brass from the cleaning media. I had run a load through, and sat the plastic tumbler thing on my loading bench (full of clean brass) next to the scale. What the heck, the scale just tipped?!?! Pull it away, scale zeroes. Put it back, scale tips. This is weird. I'm not touching the scale, and I'm not touching the bench. It's like the magnetic field is being disturbed, but it's not a magnetic scale- and the tub is plastic!

What the heck is going on? Subsequently I tried getting just the brass close & it didn't affect it. I tried just the plastic bucket & there it is. I tried some other plastic things I had around and nothing. I'm stupefied.

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Fishslayer
January 28, 2012, 12:39 AM
Static attraction.

Try rubbing the plastic with a drier sheet & see what happens.

GJgo
January 28, 2012, 12:41 AM
That certainly seems plausible, however I didn't "feel" any static on / near the plastic. Doesn't mean it wasn't there I suppose.

chhodge69
January 28, 2012, 12:42 AM
Your flux capacitor is creating an inverted warp field and knocking the power coupling out of phase.

788Ham
January 28, 2012, 01:02 AM
STATIC ! Rub a blown up balloon on your head, then put it next to a cat, notice how the hair stands up? STATIC my man! Science 101.

GJgo
January 28, 2012, 01:13 AM
I think I'm gonna go with the flux capacitor suggestion. :P

Certaindeaf
January 28, 2012, 01:51 AM
Burn some sage. Not me though.

blarby
January 28, 2012, 03:09 AM
Magnetic dampener.

Static electrical field.

There ya go :)

twofifty
January 28, 2012, 03:31 AM
Whatever you do, DO NOT p on that plastic tub !




;)

redneck2
January 28, 2012, 08:17 AM
STATIC ! Rub a blown up balloon on your head, then put it next to a cat, notice how the hair stands upYeah, but then do you put your head, the cat, or the balloon next to the scale??

:D

GJgo
January 28, 2012, 10:18 AM
No way is my cat getting near my bench! :D

steve4102
January 28, 2012, 10:45 AM
Magnetic dampener.

FROGO207
January 28, 2012, 10:54 AM
I have been trying to teach my cat how to reload for years.:cool: All he will do so far is push the buckets of brass off the shelf and bat the individual casings around on the floor. This usually happens between 1AM and 4 AM.:banghead:

Yeah all that media running around in the tub is creating a static charge that is attracting the scale beam. If your scale is drifting any try cleaning the knife blades and the ceramic holder with a Q-tip dipped in rubbing alcohol. This usually will stop most problems.

JohnM
January 28, 2012, 11:05 AM
It's a charge being built up in that plastic separator. Plastics are among the most complex compounds around.
Whichever ones used in yours evidently is good for holding a charge.
Just keep it off the bench and away from your scale.
Helps to have a pack of those anti static computer wipes around for wiping down some of the plastic items we always end up having on our reloading benches.
Don't talk to me about CATS! :D
I got one that always wants to come into the reloading room to see what I'm doing.

The Bushmaster
January 28, 2012, 11:24 AM
Steve4102 has it. The 5-0-5 is magnetically dampened and the static buildup in the plastic seperater is the cause.

The change you are seeing in the first thing you noticed in that the scale changes from day to day is +/- .1 is caused by atmospheric pressure.

OR you might check for space alians outside your window.

The Grand Baboon
January 28, 2012, 11:54 AM
Your flux capacitor is creating an inverted warp field and knocking the power coupling out of phase.

^^^^

Certaindeaf
January 28, 2012, 12:27 PM
It might just be a static buildup. Never know, man!

CHALK22
January 28, 2012, 01:09 PM
Get your reloading room wired for 220v 3-phase, and then install a voltage inverter, drop it down to 12 volt, and install one of those auto air purifiers. That oughta do it. :-)

Lost Sheep
January 28, 2012, 03:15 PM
The change you are seeing in the first thing you noticed in that the scale changes from day to day is +/- .1 is caused by atmospheric pressure.

Can anyone explain how this works?

I can understand static attraction. I can understand magnetic influence. I can understand air movement. I can even understand capacitance. But air pressure?

Anyone?

Lost Sheep

rcmodel
January 28, 2012, 03:21 PM
Air pressure or air density would not change a scale zero because it would be applying pressure equally all over the scale.

Air temperature could change it 0.1+/- due to expansion or contraction of the scale beam.

rc

kennedy
January 28, 2012, 09:16 PM
wipe the plastic with a dryer sheet

FROGO207
January 28, 2012, 09:45 PM
With a oil dampened scale I could see your actual dampening time changing due to the oil density changing with the atmospheric pressure----IF you could measure that small a difference with your scale. I would be more inclined to think that the moisture in the air (humidity) was allowing the wood of the floor joists, floor, and/or table to expand and contract at different rates and causing the table to tip slightly while gravity acting on the balance arm was remaining the same hence your small movement.;)

788Ham
January 29, 2012, 12:12 AM
redneck2,

YES!

exbrit49
January 29, 2012, 12:41 AM
The Plastic container is carrying a static charge and hence creating a magnetic field that is screwing up the magentic damping on the scale.
As suggested you can use a dryer sheet to try to help dissipate the Static and EMI fields.
Increasing the humidity might help but I doubt it will help that much. Get the plastic container well away from the scales. the field EMI field can extend several feet.
Static is generated by friction , you have seen people rub balloons and have then stick to everything, think of the media in a tumbler constanlty moving against the container surface, I bet its getting up there close to 20KV!
I bet if you ran a static Voltage meter on that Tumbler container its probably carrying well over 20 to 30 KV.
Roger

ScottRiqui
January 30, 2012, 10:01 PM
Static electrical fields don't generate magnetic fields.

You may still be seeing an attraction from the static field alone, just like a plastic or glass rod with a static charge on it will attract small scraps of paper.

1SOW
January 30, 2012, 10:43 PM
A negative potential is "attracted" to a positive potential. Thats why you get static shock "just before" you touch the door knob. It "jumps" the gap. Larger the charge, the bigger the "jump" can be. If you could touch it before it arcs, you wouldn't get "zapped".

A charge moving through a conductor does create a circular field around the conductor.
Can't remember if it's the right hand and thumb direction or left hand, but it's there. :uhoh: :eek:

Elkins45
January 31, 2012, 12:00 AM
It's called the right hand rule, but it really should be the left hand rule because physics uses conventional current.

The magnetic damping of the scale isn't involved here. Its purely an induced static reaction. This phenomenon has been reported on in reloading articles before.

1SOW
January 31, 2012, 12:08 AM
Thanks Elkins45. Motors, fields, induction---46 years ago is long time for me to remember 'anything'.;)

Striker Fired
January 31, 2012, 12:46 AM
If your running the tumbler on the same table/bench as your scale,the fine vibrations could be turning the zero knob on your scale and causing it to be off every day. I made a seperate ledge that only my scale goes on,nothing else amd it is isolated from the benck.
Either that or you have some elves coming into your room everynight and turning the knob,while gigling like school girls.

Lost Sheep
January 31, 2012, 01:57 AM
It's called the right hand rule, but it really should be the left hand rule because physics uses conventional current.

The magnetic damping of the scale isn't involved here. Its purely an induced static reaction. This phenomenon has been reported on in reloading articles before.
Following electrical current, it is the right-hand rule. Following the actual movement of the electrons, it is the left-hand rule. As my high-school physics instructor pointed out, "Electrons are left-handed".

Electrons were named by the ancient Greeks. They had no idea if they were positively charged or negatively charged. Or even that they were distinct phenomona with a discrete electrical charge. Centuries later, the rules of magnetism and electricity were being formulated and some physicist had to pick positive or negative...and chose wrong. So if the current is flowing one way, the electrons are actually moving the other direction.

Lost Sheep

gamestalker
January 31, 2012, 02:58 AM
Yep, the 5-0-5 is magnetic dampened. Mine will go bannas if I have my tumbler any where near it. Satic is also a problem, but primarily watch out for any electric motor within 5' or so of the scale. I've also heard that some types of lighting will also mess with them.

1SOW
January 31, 2012, 10:50 PM
Following electrical current, it is the right-hand rule. Following the actual movement of the electrons, it is the left-hand rule. As my high-school physics instructor pointed out, "Electrons are left-handed".

The triangle with a verticle line at the point symbol for a diode, shows negative to positive current flow.
At one time, the AF and Navy schematics were drawn "opposite" to each other for this symbol. :uhoh::D

twofifty
February 1, 2012, 12:58 AM
^ no surprise there, ya gotta protect your own turf.
A great way to make the other side's techs look like dummies when in fact they aren't.

The Bushmaster
February 1, 2012, 11:02 AM
GJgo...

Conferring with RC and running a test with my RCBS 5-0-5 this is my findings.

I set up my 5-0-5 on my loading bench and checked for level with a small (bullet) level and set my beam scale to "0" three days ago. Noting that the level had a rather strong magnet in it's base I ran the level over the scale with absolutely no effect to the scale's setting. I then let it set (under a fluorescent light (four tube) and ocassionally bumped it and opened the window in my man cave once in a while.

My RCBS 5-0-5 beam scale never moved from "0" at any time and when bumped or jiggled while I was working on the bench it always returned to "0".

Conclusion: In my opinion nothing much effects the 5-0-5. At least not mine. I didn't try the static electricity part of this because I figured that the strong magnet test was enough. Besides the only thing around my house with static electricity is me and my dog tends to stay away from me.:D

One thing I might suggest is that you have a look at the beam fulcrum knife edges and the rest they set in with a magnifying glass. Look for dirt, nicks on the knife edges and deformities in the fulcrum rests.

RC...I take back what I said about atmopheric pressure having an effect on the scale. You are right. Because of equal pressure there is no effect at all. In my area we have gone from a high pressure to a low pressure and back again and the scale remained at "0"...

brickeyee
February 1, 2012, 04:00 PM
"I didn't try the static electricity part of this because I figured that the strong magnet test was enough."

Wrong on so many fronts.

Non-magnetic materials that are not moving relative to a magnetic field will not be influenced by the field.

ANY conductor moving in a magnetic field IS influenced.

THAT is how a 'magnetic damper' works.
As long as the damper is moving it is affected by the fixed magnetic field by eddy currents.
One it stops moving no force is exerted is the metal is not ferromagnetic (the small paramagnetic affect is not enough to cause issues with a powder scale).

Static electricity creates an electric field that can exert forces on conductors or other charged objects.
Static electricity on a non-conductor (like most plastics) is on the surface typically and generates an electric field, and with a scale as sensitive as a powder scale made from metal it can affect readings.

To remove static electricity from a non-conductor you need to wipe the entire surface with a grounded object, or put something on the surface that can allow the static charges to bleed off or recombine (and cancel).

Even a very high resistance path is more than enough to bleed of static electricity.

GJgo
February 1, 2012, 10:56 PM
I think I might need one more guy to say it's static before I'll beleive it. :P Just kidding, "cleaned" the charge off the plastic tub and no more interference so problem solved.

I did a close inspection today in the fulcrum edge & seat, they're both perfect. I always thought maybe the +/- 0.1g day to day could be from the position of the Earth in its rotation, maybe magnetic north floating. haha

rcmodel
February 1, 2012, 11:07 PM
O.K.
It's Static Electricity in your Shorts.

Stop rubbing cat fur on them, and shuffling your bunny slippers on the shag rug, and your scales will work right again!

There, I said it.
But, The Dabble made me say it! :D

rc

The Bushmaster
February 2, 2012, 10:59 AM
Why thank you...No wonder they call you brickeyee.....:p

TonyT
February 2, 2012, 12:32 PM
Perhaps the magnet in the motor of the tumbler?

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