Group buy: high grade PTFE-coated cylindrical magnets
edited February 2015 in Everything else
Hi all! I'm new here. A friend of mine asked me to host a group buy for teflon coated Alnico 5 magnets from BOLA, as they don't sell to individuals (I have a registered company).
Several people on the IRC have already said they want some, so I was wondering if anyone else here was interested. The price is about 1.53 euro each for 5x2 magnets (length x dia, in mm), or 1.23 euros per 7x2 magnet, excluding the shipping to you (which will probably be less than 3 euros per person). The magnets are FDA conform and have excellent universal chemical resistance. They are sold as stirring bars, which means they are made to endure a lot of mechanical stress.
We picked these because they would be easy to implant by injecting them using a hypodermic needle, removing the need for scalpels or suturing. The cylindrical shape should also significantly reduce the chance of the magnet flipping around inside the finger.
There are also other sizes available. 8x2 costs 1.44, 6x3 costs 1.20. There's a minimum order amount of 10 for sizes other than 5x2, unless others are interested in the same size too.
Let me know if anyone is interested in a bunch of these. I accept wire transfer, PayPal and Bitcoin.
as rdb pointed out. it is very hard to predict the final preceived sensivity.
the field strength itself is by far the least concern. it falls off extremly rapid if you move away from the magnets surface. if anything about fields would be of importance, then it is the strength and size of the field you want to feel.
this will also determin the overall magnetic flux that'll be flowing. and that in turn will give you the forces that occur at the magnet. and those , depending on the magnet's shape and size, will press/vibrate/rotate against the surrounding tissue. which would be the end of the mechanical sensory chain.
piking a stronger magnet will do very little, compared to moving your magnet a bit closer into the field.
having a bigger magnet will give you a bigger force, but that distributes over a bigger area so there is less pressure to be sensed. while having a long thin magnet will give you a higher angular force ,but at thesame time the shape is a longer lever so the tissue can counteract with less force to be sensed.
one thing about smaller magnets is their smaller mass, which means less inertia, which does allow them to move faster given weak fields.
long story short: impossible to squeeze into a spreadsheet with just a few squareroots. if you want to calculate, you wont get around a lot of really nasty math. not counting mathematical models that could give you a number on preceived magnet motion.
to sum up a few points from above.
compared to most of the magnetic disks people implanted in the past, these magnets are quite a bit smaller already.
compared to N50, these magnets arent quite as strong, but they are still pretty strong and on top of it, alcino is very very long-term stable when it comes to its magnetic properties.
compared to some magnets from some factory somewhere in china with unknown quality standards, these magnets are lab-grade FDA approved quality.
compared to the smaller parylencoated neodymmagnets, these have a pretty thick coating which makes them more robust(biologically and mechanically). (besides PTFE wont connect to the tissue so it'll be easier in case you want them removed)
last but not least they cost only a fraction of the smaller neodym-parylene ones (and can be ordered in lower quantities).
there is no garuentee for excellent performance. so the biggest risk is that they wont work, but chances of breaking, poisoning etc are very low with these.
so they are well worth to be tried out. we are still experimenting after all, otherwise we wouldn't be searching for the "perfect" magnet to implant.