Group buy: high grade PTFE-coated cylindrical magnets



  • Cool! When will you start send them?
  • I'll be shipping most of them off within the coming week.  Starting next weekend, I'll be going on a two-week vacation, so I will be unavailable during that time.

    I can't say much about sensitivity yet.  I've tried gluing one of them to my fingertip, but that doesn't work as well for these tiny cylindrical ones as it does for the bigger disk magnets, probably due to a variety of factors.  I guess there's no way to know for sure how sensitive they will be unless someone injects one.  For me, that'll have to wait until after my vacation.
  • I'm ordering my needles and will inject mine the moment they are in my hands and I've set up a works space. 
  • Jack,
    Where did you get your injecter from?
  • rdbrdb
    edited June 2012
    I've shipped off everyone's 5x2 magnets (except for a few people I have other arrangements with, and for the one person who hasn't paid yet).  Please let me know when they arrive (PM or otherwise), and make a post with details when you've implanted one.

    If too many were shipped, consider the extra ones a gift.  If too few were shipped, contact me, I must have made a mistake.

    I'll let you guys know when the 7x2 magnets are in.

    Happy implanting everyone!

    PS.  There are some links to sites that sell RFID applicators on this thread.
  • My magnets arrived today, I'm planning implanting one in my left ring finger after the summer :D
  • Mine just arrived ten minutes ago, all I need is the needles I ordered to arrive and they're going in.

    I didn't expect them to be this weak or small. Smaller being a plus, weaker a minus, oh well they're going in anyways. It's the only way to see how they act. Thanks rbd. 
  • Received mine today as well, though I might not be implanting for another month or two.  Can't wait to hear how yours turn out, Jack.  
  • I'm thinking of implanting one of mine this week. These do react quite a bit to my other implant. I can kind of make one hover slightly by getting close with my finger.

    They don't have much strength, which is to be expected. But they also aren't n-52s. The point of these is for the sense of touch... So I'm likely going to put one on my ring finger right hand. This way I can
    Compare my Haworth implant to this in terms of feel.
  • I put one of these in my right ring finger today.  Let me tell you, doing this yourself and with your left hand is not easy.  To make matters worse trying to insert the magnet in to the hole/tunnel I made was more challenging than threading a needle.  

    I did not have the injection needle of a size that would work.  14g is as big as I had and that just won't cut it.  I believe a 12g may just fit perfectly.  I used a 14g needle to make a hole and tunnel, bypassing the scapel.  I used a metal rod I had to dilate the hole I made.  Then the fun of trying to get that tiny magnet in that hole/tunnel.  

    I managed to finally get it in after taking my glove off and using my sense of touch to slide it in.  I pushed it down with a piece of plastic and thought I was good to go.  Nope.  I squeezed my finger a little and out popped the implant.  Like popping a zit.  I repeated what I did before I put two sutures over the hole to hopefully keep it from coming out.  I can't really tell exactly where the magnet ended up yet.  After it heals a little and the numbing is gone I should know.
  • @Shishou i am pretty excited to hear you already implanted one. 12g was indeed the recommended size as it is the same size used for most rfid tag applicators (which are supposed to make the whole implanting procedure easier to handle)

    i'm looking forward to your experience with the new magnets.
  • I highly recommend implanting with a 12g needle or RFID applicator. Implanting these like other magnetic implants is such a pain in the ass. The north and south of the magnet is on either end of the cylinder so using tweezers to try and put it in was a disaster. This also makes me worry about the design. I feel disc shaped may be best.

    I checked where my implant was today and I couldn't push it down the tunnel I made and it is instead closer to the opening. So the magnet is to the left and above the middle of my finger pad. Which should be fine for its purpose once it heals.
  • As of right now I just started being able to feel some stronger waves with this implant. It is a bit higher and off to the side more than I had intended, but it should do it's job.

    Although my Haworth implant is in softer tissue and a week further in recovery... I notice the waves farther and stronger with this implant. I am not sure if this is due to these not being n-52 like the Haworth implant or due to the size. I also theorize the disc-like shape is superior to the cylinder. Only because the north and south poles are on different ends of the cylinder while top and bottom on disc.

    Of course I still have a bit of healing to do before I can accurately judge. If anyone has some suggestions of what gives off good waves for me to feel, I'd love a list so I can better compare.
  • Keep us posted!
  • Shishou, am I reading your above post correctly if I come away from it thinking that the 2x5mm magnets from this buy are giving you a greater sense of ... magnet-touch? than the Haworth one?
  • You would not be reading it correctly.

    As of right now I get 4x the distance of feel with my Haworth implant. But there are some factors to consider too.

    -Haworth implant is in softer, more fleshy part of my finger. As well as close to the surface under the skin.
    -n52 strength on Haworth versus n32(?) on this implant.
    -This implant I could not ideally position due to the shape and size. Not to mention I did it left handed alone.
    -This implant is very close to the insertion spot. The skin there healing is very rough still with lots of scar tissue. This means it may take much longer healing for this implant to get a fair judgement.
    -Haworth implant was put in a week before this one and has longer healing time.

    Honestly I am being a bit doubtful on this comparing positively versus the Haworth implant. Mainly because of the different magnet strength.

  • hm. the difference in magnetic strength is one thing. the magnet itself won't do anythin unless it enters a magnetic field and that's where the math get's nasty. but the distance between the magnets make a very big difference in the forces resulting on the magnets. given the math, doubling the distance should drop the resulting forces by a factor of 8 to 16, depending on what sort of motion/force from the magnet actually gives the sensation.

    given the cylindrical implants have an alnico-core, which has a surface-field strength of about 0.15 T and the Haworth implant are N52 which are about 1.43T that would a factor of 10 difference. so a reduction to half the range would be an expected result. the other 2x distance (which is another 8 to 16x in actual sensivity) should fall in one of the cathegories you mentioned. healing in progress, implant position, scar tissue, maybe even the shape.

    on the other hand. it is good news that you are able to feel anything with them already. i am looking forward to more news from you. keep up the spirit.
  • Do the waves only affect one pole on a magnet? I know half of this implant is under tough scar tissue which may be causing this feeling... When I feel waves it seems like only one end of the implant reacts.
  • They should make the magnet tilt around its axis (remember, these are designed as stirring bars), so if that's not happening, then it must be that half of the implant is in tougher tissue.
  • So, Shishou, how's the lil implant going?
  • Worthless.  I am probably going to remove it and implant one of the n52s I have in the near future.  I can only really feel that I even have this implant if I am around a very strong force or use a powerful magnet to move it.

    The placement of it and possibly even the shape causes it to sting if I grip something tightly with that finger.
  • That's a real shame.  Do you think it's the PTFE coating that's to blame or the relatively weak Alnico core?  I've been having a lot of difficulty sourcing stronger PTFE-coated magnets, which is a shame, because of the advantages of PTFE.
  • If you find a good source, let me know.  I'm still looking for a replacement to mine.  I'm in the same boat as Shishou at the moment.
  • I have ordered some 1/16 x 1/4 inch NIB cylinder magnets, but they do not have a protective coating.  I am looking at the possibility of encasing them in bioglass, but if that does not work out I will probably be investigating some other type of coating.  Does anyone have advice on how to coat these to make them safe for injection?  The last thing I want is to have to pull a disintegrated magnet out of my body and I have done enough research to know that some type of coating would be required.

    If I am unable to coat/encapsulate these properly at home, I am open to suggestions regarding having this done by someone.  Since 1/16 inch is smaller than 2mm, I should be able to use a pet injector to implant this.

  • There is PTFE shrink tubing.  I believe that ThomasEgi had some ideas on using that to encapsulate an implant.
  • PTFE is not the issue at all you. You can coat items in teflon at home. For example, ( here is a spray form to repair pans.

    The issue is TEMPERATURE. This is why V&P makes such a big deal about mag stirrers made of Neodymium.... it hadn't been done before. Neo loses its strength if heated above 350 F or so, and coating in Teflon requires about 500 F.
  • So, in terms of using Teflon, it might be good for other more temperature stable projects, but if you use Neodymium, then it's not going to happen.
  • I don't know what a "350 F" is (please use standard units) but I think that the temperature you need depends on the method that you use (compression molding, heatshrink tubing, sintering, etc.)  Also, perhaps you can insulate the magnet from any high temperature long enough using another material.

    Keep in mind that you should never heat PTFE beyond 250 degrees celsius (which is, by the way, lower than its melting point) because pyrolysis happens at this point.

    I believe that PTFE heatshrink tubing shrinks at much lower temperatures though, but I don't have the datasheet to back that up.
  • (350 degrees F - 32) * 5 / 9 =  160 degrees Celsius.
  • Uh, standard units? How about 449.8 kelvin?
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