Hi Chris and all,

Excellent work Chris!!!  Just finding good diamagnetic material is
rather very rare, and to have it commercially available and also
strongly diamagnetic (a form of pure graphite) is very significant
indeed!

In another relation to James website; the specific magnet/s
used are currently being re-ordered by Forcefield/Wondermagnet,
so the availability of such "could be" in the neighborhood of a
number of weeks (5-7 weeks?).  One precaution; the magnets
need to be handled with alot of care, they do break easily....
one needs to firmly but gently, slide, the magnets onto iron/steel.

I think myself, that after viewing James seismograms, the instrumental
response was rather good for nearby and/or the stronger distant quakes.
For the very small size of the diamagnetic sensor itself, I think its
most
significant!  Along with the graphite and magnets, it would seem like
this
approach in the sense of cost is really going cheap....and now (soon)
quite available.


ChrisAtUpw@....... wrote:

> Hi All,
>
>       In response to James Spottiswoode's graphite seis rig at
> http://www.jsasoc.com/diamagnetic_suspension_seismomet.htm I took a
> magnet setup into my local arts materials / stationery suppliers and
> went through their stock of pencil leads. I can confirm that Faber
> Castell O.7 mm x 60 mm 2B leads are strongly diamagnetic. 12 off cost
> $1. None of the larger ~1/16" leads that I tried were diamagnetic.
>
>       Cyanoacrylate glues seem to stick graphite more or less OK.
> Epoxy will stick Graphite very well, but it doesn't like water at all.
> Cold Graphite is covered with several layers of water and you have to
> drive this off first, by heating it to more than 150 C before you can
> glue it with Epoxy. Possible heating sources are hotplates on electric
> stoves and soldering irons. Epoxy is mildly diamagnetic.

Good glueing notes Chris.  I've used Permabond 268 once recently on
graphite, and it seems to hold very well once cured (no prior heating).
Its also easy to sand/file off any excess.  Permabond F246 (that you've
recommended also), is also excellent but expensive and difficult to
obtain in America.  I think instant glues eventually separate as they
are not too water/moisture resistant.  Its a big unknown world with
various glues around to try.

Take care, Meredith






Hi Chris and all,
Excellent work Chris!!!  Just finding good diamagnetic material
is

rather very rare, and to have it commercially available and also

strongly diamagnetic (a form of pure graphite) is very significant

indeed!
In another relation to James website; the specific magnet/s

used are currently being re-ordered by Forcefield/Wondermagnet,

so the availability of such "could be" in the neighborhood of a

number of weeks (5-7 weeks?).  One precaution; the magnets

need to be handled with alot of care, they do break easily....

one needs to firmly but gently, slide, the magnets onto iron/steel.
I think myself, that after viewing James seismograms, the instrumental

response was rather good for nearby and/or the stronger distant quakes.

For the very small size of the diamagnetic sensor itself, I think its
most

significant!  Along with the graphite and magnets, it would seem
like this

approach in the sense of cost is really going cheap....and now (soon)

quite available.

 
ChrisAtUpw@....... wrote:
Hi All,
     
In response to James Spottiswoode's graphite seis rig at h
ttp://www.jsasoc.com/diamagnetic_suspension_seismomet.htm
I took a magnet setup into my local arts materials / stationery suppliers
and went through their stock of pencil leads. I can confirm that Faber
Castell O.7 mm x 60 mm 2B leads are strongly diamagnetic. 12 off cost $1.
None of the larger ~1/16" leads that I tried were diamagnetic.
     
Cyanoacrylate glues seem to stick graphite more or less OK. Epoxy will
stick Graphite very well, but it doesn't like water at all. Cold Graphite
is covered with several layers of water and you have to drive this off
first, by heating it to more than 150 C before you can glue it with Epoxy.
Possible heating sources are hotplates on electric stoves and soldering
irons. Epoxy is mildly diamagnetic.


Good glueing notes Chris.  I've used Permabond 268 once recently
on

graphite, and it seems to hold very well once cured (no prior heating).

Its also easy to sand/file off any excess.  Permabond F246 (that
you've

recommended also), is also excellent but expensive and difficult to

obtain in America.  I think instant glues eventually separate
as they

are not too water/moisture resistant.  Its a big unknown world
with

various glues around to try.
Take care, Meredith