DIY Stirplate questions

Hi all. I'm working on a stirplate & I had a couple questions. I've pulled some rare earth magnets out of an HDD, but I'm having trouble separating them from the metal pieces their bonded to. Recommendations on how to remove them? Also - I'll be using a 1L flask for my starters. Would you recommend a 1" or 2" stirbar?

Thanks!
Michael

I used 2 pairs of large vise grips and bent the mettle until the magnet separated. I think you could also try to hit the magnet with a hammer / wood block to knock it lose. 1" stirbar should be fine in a 1L flask I would think.

I put the metal brackets in a bench vise, and begin to lightly tap the area where the magnet is attached to the brackets with a flat head screwdriver. If you are very careful and take your time, you will not break the magnet. I've tried the vise grips method, but ended up putting too much stress on the magnet and broke it.

I put the metal plate in a bench vice and used a set of pliers to bend the plate and the magnet released rather easily... after i tried to knock the other magnet off the plate and ended up shattering the magnet ( oops!)

i agree a 1" bar will be fine for a 1L starter

A little off topic but has anyone tried the starburst stir bars? I just bought one like this on ebay. Should be here next week so I'll update then.

The starburst one is what I use. It works great.

kebrown said:

The starburst one is what I use. It works great.

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That starburst stir bar is 1-1/2" wide. How do you get that down the throat of a flask? I don't think my 2 liter flask has an opening that large. Otherwise, I think I might like to try one of these.

I just posted the same statement on another thread yesterday. Yes the 1 1/2" stirplate will fit in a 2L flask. The throat of mine is about 1 3/4".

Damonic said:

I just posted the same statement on another thread yesterday. Yes the 1 1/2" stirplate will fit in a 2L flask. The throat of mine is about 1 3/4".

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Sorry about that! I thought that somehow the first time didn't get posted. Might have been due to too many beers yesterday.

Stand the magnet with its metal backing on a piece of wood in the vertical position, use a single edge safety razor and tap the edge down between the magnet and the metal frame. The magnet will seperate with a little work just takes a few taps with a small hammer. Once broken loose a scewdriver to apply a side pressure on a shear with the magnet. Some of the chrome plating will stick to the metal frame. I still have 24 of these thick magnets in a tall stack stuck together, they have one heck of a pull and will cause a blood blister. I went thru a rack of hard drives from Sun Micro Systems, spent over 6 hours on a mission taking them apart to get the magnets out. These are thick magnets at 0.142" thick not the thin ones at 0.070" thick. I have them in a safe place away from everything as they are so strong and dangerous.
I am willing to sell these as a unit of 24 magnets as I have two for my own yeast stir use. Any "fair" offer and all 24will go as a single unit plus shipping will be added that will be minimal. They must be placed in a box 10" x 10" x 10" for safety reasons for shipping, that would be UPS ground for a cheap rate. This should of been placed on the for sale section but i'll sneak it in like I have seen other memebers have done in the past with their off topic items but these are related to stir plate magnets.
PM is OK with me. Carl......

OGreuelRules said:

Hi all. I'm working on a stirplate & I had a couple questions. I've pulled some rare earth magnets out of an HDD, but I'm having trouble separating them from the metal pieces their bonded to. Recommendations on how to remove them? Also - I'll be using a 1L flask for my starters. Would you recommend a 1" or 2" stirbar?

Thanks!
Michael

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I have not come across a magnet that was actually "bonded" to the bracket (not to say they aren't, I just haven't seen one) , save for a tiny tack weld at one end. I was surprised how strongly these magnets actually are, and it takes quite a bit of force to remove them.

Look for the weld, and chip it away as carefully as you can. If there is nothing obvious holding it down, take a small flat blade screwdriver and gently working it around the edge until it lifts off. You'll need to be careful though, as for as strong (holding power) as the magnets are, they chip remarkable easy.