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Restoring and replacing meter scales - brass vs. aluminium backer?

 

I need to restore my Tek 130LC meter scale - the red has unsurprisingly 95% disappeared.

I've crafted the artwork, and boy did that take some time as each of the five scales is cunningly non-linear and no two appear the same!

It's now about print and apply, but apply to what? I'd rather keep the original aluminium-backed scale safe as I may have a way to restore it without removing/affecting the existing visible print. What I do have to hand is plenty of suitably thin brass sheet. I'd need to buy aluminium in.

Am I correct that brass is equally suitable, will have an equal impact on meter calibration/accuracy, but might possibly confer slightly more damping?

However, having spent SO long producing the exact artwork, would be shame to undo that with the wrong material!

I just don't have the practical experience here, so would value your thoughts. Thanks.
 

Can't you apply the new scale to the back of the existing plate?
73,
Bill, WA2DVUCape May

On Friday, January 24, 2025 at 02:45:54 AM EST, Richard Kelly via groups.io <richardjkelly@...> wrote:

I need to restore my Tek 130LC meter scale - the red has unsurprisingly 95% disappeared.

I've crafted the artwork, and boy did that take some time as each of the five scales is cunningly non-linear and no two appear the same!

It's now about print and apply, but apply to what? I'd rather keep the original aluminium-backed scale safe as I may have a way to restore it without removing/affecting the existing visible print. What I do have to hand is plenty of suitably thin brass sheet. I'd need to buy aluminium in.

Am I correct that brass is equally suitable, will have an equal impact on meter calibration/accuracy, but might possibly confer slightly more damping?

However, having spent SO long producing the exact artwork, would be shame to undo that with the wrong material!

I just don't have the practical experience here, so would value your thoughts. Thanks.
 

Indeed, but I'd rather not risk damaging the original.

I've got some 0.5mm aluminium sheet after all, so I will use that.
 

On Thu, Jan 23, 2025 at 11:45 PM, Richard Kelly wrote:


Am I correct that brass is equally suitable, will have an equal impact on
meter calibration/accuracy, but might possibly confer slightly more damping?
Al is paramagnetic. Brass... depending on what's in it... is supposed to be diamagnetic.
Brass has about 1/2 the conductivity of Al.
I thought the meters in those 130 were of the D'Arsonval type... and as such.. the 'damping' is done the eddy currents generated in the Al bobbin the meter coil is wound on.
The magnetic fields are 'tightly' confined to vicinity of the coil; because there is an iron core, inside the bobbin.
AFAIK, what's moving is the bobbin, not the meter face plate.
Don't know if the meter face plate is used for shielding... if that's the concern... but either brass, or Al, won't shield against magnetic fields... and while Al is better at shielding strong electric fields... AFAIK... practically brass is as good.
--
Roy Thistle
 

Take care to avoid brass and aluminum from direct contact with each other. Dissimilar metals result in corrosion if moisture and a current path are present. It might not be a big deal for your meter face but be aware.
 

I don't know about your particular meter but most plates are symetrical and could be flipped over. If so you could apply the new artwork to the reverse side of the plate.

Bill Koski

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