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Specialty Chemistry Forums => Other Sciences Question Forum => Topic started by: CheapBastid on November 29, 2012, 01:02:18 AM

Title: Old Magnestir vibrates - suggestions?
Post by: CheapBastid on November 29, 2012, 01:02:18 AM
Hello!

I picked up a cheap old Magnestir s8290 and it works fine until I get the dial about 1/2 way turned up, then a buzz starts that increases to the point where the container starts moving.  If I keep going the whole unit starts to crawl across the desk.

I opened it up (four screws) and nothing seems to be loose, it appears that the motor vibrations are the culprit.  I was thinking of picking up some rubber washers to reduce the transfer of vibration from the motor to the case, but I wondered if anyone's experienced this issue and had a tested solution.

Thanks!
Title: Re: Old Magnestir vibrates - suggestions?
Post by: curiouscat on November 29, 2012, 01:58:28 AM
I've seen that in units I used too during my long past undergrad days. My solution was to clamp my flask separately to a stand and then jam the unit against a heavier cabinet so that it wouldn't start crawling around.
Title: Re: Old Magnestir vibrates - suggestions?
Post by: Arkcon on November 29, 2012, 08:05:56 AM
Another trick is to replace its feet with sawed off rubber stoppers.  They're much denser than the standard rubber feet.  They aren't as good at dampening slight vibrations, but heavy vibrations, like you're experiencing, can't "walk" the stir plate across the bench.
Title: Re: Old Magnestir vibrates - suggestions?
Post by: curiouscat on November 29, 2012, 09:01:37 AM
Another trick is to replace its feet with sawed off rubber stoppers.  They're much denser than the standard rubber feet.  They aren't as good at dampening slight vibrations, but heavy vibrations, like you're experiencing, can't "walk" the stir plate across the bench.

That gives me an idea. Have you seen the anti-skid mounts for keeping cell phones on car dashboards etc.? That polymer mat has an incredibly high friction coefficient. Try cutting pieces off something like that or just place your stirrer on one.

It's next to impossible to make those things slide!