Standard block care

[Dan R]

Hello all,
I'm wondering what other labs do to keep their standard blocks clean and in tip-top shape over time. I've noticed that some of my pure metal standards are developing an oxide layer that is interfering with my standardization (especially when analyzing fresh new alloy surfaces).

We have sent one standard block back to the manufacturer to be resurfaced and cleaned, but we were not very satisfied with the results... Is re-polishing the surface typically the only way to refresh the surface? I was thinking about trying our plasma cleaner, but I wanted to see if anyone else has had experience going that route.

Also, if anyone has any good best practices for how they keep their standards when not in use, I'd like to hear about them. We keep our standards either in a dessicator or the instrument and always handle them using gloves.
Thanks for any input!
-Dan

[Probeman]

Hello all,
I'm wondering what other labs do to keep their standard blocks clean and in tip-top shape over time. I've noticed that some of my pure metal standards are developing an oxide layer that is interfering with my standardization (especially when analyzing fresh new alloy surfaces).

We have sent one standard block back to the manufacturer to be resurfaced and cleaned, but we were not very satisfied with the results... Is re-polishing the surface typically the only way to refresh the surface? I was thinking about trying our plasma cleaner, but I wanted to see if anyone else has had experience going that route.

Also, if anyone has any good best practices for how they keep their standards when not in use, I'd like to hear about them. We keep our standards either in a dessicator or the instrument and always handle them using gloves.
Thanks for any input!
-Dan

Hi Dan,
The method I've seen used to mount standards (metal mounts with set screw fixed sleeves) makes it very difficult to clean these types of mounts. If possible you should mount your own standards in an acrylic block as described here:

http://smf.probesoftware.com/index.php?topic=172.msg1436#msg1436

Then cleaning is just a few seconds of colloidial polish followed by a wipe of ethanol and oven dry, then carbon coat.  Once every 5 years or so we go back to a diamond hard lap to remove relief from repeated coloidial polishing on the soft lap.

Because this cleaning is so easy we often polish our standard mounts several times a year or more at UofO to keep them pristine.

But to answer your question, we keep them in a dessicator with fresh dessicant.
john

[jtmitchell]

Hi everyone,

I'm doing some window-shopping for my lab now that I've been in post for a while and would like to make some upgrades, and I was curious as to how everyone is storing their standards? I'm keen to see if there's anything I could be doing differently, or if anyone has any creative ideas on keeping them safe and fresh. I suppose I'm most interested in how everyone is wrangling their metal standards, especially as I've got a growing user base who need them on a regular basis.

Thanks

- Jen

[Probeman]

I'm doing some window-shopping for my lab now that I've been in post for a while and would like to make some upgrades, and I was curious as to how everyone is storing their standards? I'm keen to see if there's anything I could be doing differently, or if anyone has any creative ideas on keeping them safe and fresh. I suppose I'm most interested in how everyone is wrangling their metal standards, especially as I've got a growing user base who need them on a regular basis.

Here's what we use in our facility. It's a Secador brand dessicator:





To keep things dry in there we have a bunch of dessicator gel packs in the bottom of the dessicator.

[crystalgrower]

If your mount has oxide then you need to repolish,  Preferably using an oil based media.  Degrease with a 5 minute dip into clean isohexane, dry quickly, coat promptly.

Store mount with carbon coating in place and in a dessicator.  Preferably a manager-only dessicator.

It helps to keep standard blocks with a few of those small dessicant bullets in a plastic box in the larger dessicator. 

FYI a plasma etcher WILL get rid of any epoxy.  Probably not what you want.