I don't care for using magnets in molds. For the most part its unnecessary.
Once you get a feel for the mold it gets to be pretty easy to slide a hook
or a keeper into its slot. Even if you have to wear glasses like I have had
to for the last decade.

Sometimes though the only way to get a piece of hardware to stay in place is
with a magnet. This leads me to why I felt the need to post this. I
learned recently that rare earth magnets have a failing. Above a certain
temperature they loose their magnetism and that temperature is much lower
than you might think. A little higher and they lose their magnetism
permanently. These temps are below the melting temperature of lead. Now a
mold rarely gets as hot as lead. Even if you set it on top of the lead pot
to preheat, but it does get pretty hot. Hot enough that you have to wear
gloves to handle it safely. Maybe closer than you might like to
degmagnetizing temperature of the magnet.

I didn't research other magnets as I like the strong holding force of even
tiny rare earth (neodymium) magnets for these problematic applications. I
discovered that for a little more money there were higher heat rated rare
earth magnets. I check a couple sources. MSC didn't have any in a size I
wanted. McMaster had one size that was useful. K&J had them much cheaper
than McMaster, but they were further away and only shipped UPS. I ordered
from both McMaster and K&J Magnetics.

I actually had two molds that I couldn't come up with any other solution
for. The first was done with the McMaster magnets and like other magnets I
have ordered they were a little under their specified dimensions. They also
did not seem to have a hard coating like most rare earth mags I have bought
in the past. I just glued them in place with JB weld. The K&J magnets
came in a few days later, and I miced them. I took measurements on 2 or 3
out of each pack. They were all within 0.0005" of target diameter, and
about the same for target length. They also had the nice shiny nickel
coating I am used to seeing. I machined tapered holes (.001 over at the
top to .001 under at the bottom) to press the magnets into and they fit
perfectly. I expect if you rapped the mold sharply on the bench you could
knock them free, but neodymium magnets are pretty fragile. I didn't want to
break them when pressing them in.

Another thing learned. I hope it helps somebody else.

On Tue, 31 Oct 2017 11:47:47 -0700, "Bob La Londe"
wrote:

I don't care for using magnets in molds. For the most part its unnecessary.
Once you get a feel for the mold it gets to be pretty easy to slide a hook
or a keeper into its slot. Even if you have to wear glasses like I have had
to for the last decade.

Sometimes though the only way to get a piece of hardware to stay in place is
with a magnet. This leads me to why I felt the need to post this. I
learned recently that rare earth magnets have a failing. Above a certain
temperature they loose their magnetism and that temperature is much lower
than you might think. A little higher and they lose their magnetism
permanently. These temps are below the melting temperature of lead. Now a
mold rarely gets as hot as lead. Even if you set it on top of the lead pot
to preheat, but it does get pretty hot. Hot enough that you have to wear
gloves to handle it safely. Maybe closer than you might like to
degmagnetizing temperature of the magnet.

I didn't research other magnets as I like the strong holding force of even
tiny rare earth (neodymium) magnets for these problematic applications. I
discovered that for a little more money there were higher heat rated rare
earth magnets. I check a couple sources. MSC didn't have any in a size I
wanted. McMaster had one size that was useful. K&J had them much cheaper
than McMaster, but they were further away and only shipped UPS. I ordered
from both McMaster and K&J Magnetics.

I actually had two molds that I couldn't come up with any other solution
for. The first was done with the McMaster magnets and like other magnets I
have ordered they were a little under their specified dimensions. They also
did not seem to have a hard coating like most rare earth mags I have bought
in the past. I just glued them in place with JB weld. The K&J magnets
came in a few days later, and I miced them. I took measurements on 2 or 3
out of each pack. They were all within 0.0005" of target diameter, and
about the same for target length. They also had the nice shiny nickel
coating I am used to seeing. I machined tapered holes (.001 over at the
top to .001 under at the bottom) to press the magnets into and they fit
perfectly. I expect if you rapped the mold sharply on the bench you could
knock them free, but neodymium magnets are pretty fragile. I didn't want to
break them when pressing them in.

Another thing learned. I hope it helps somebody else.

Neodymium rare-earth magnets, the common type, can't tolerate much
heat. Normally, their max working temperature is in the range of 80
deg C - 120 deg C, with the latter being types designed specifically
to take the heat (I think they have cobalt in them, or maybe something
else).

In military applications and all sorts of higher-temp applications,
you'll find that the samarium-cobalt rare-earth magnets are more
commonly used. They can handle up to 350 deg C.

And good ol' ferrite magnets are usually good for 250 deg C. They,
too, are used instead of Nd magnets where higher temperature tolerance
is called for. Their strength is a lot lower but they're also a lot
cheaper.

--
Ed Huntress

"Bob La Londe" wrote in message
news
I don't care for using magnets in molds. For the most part its
unnecessary. Once you get a feel for the mold it gets to be pretty
easy to slide a hook or a keeper into its slot. Even if you have to
wear glasses like I have had to for the last decade.

Sometimes though the only way to get a piece of hardware to stay in
place is with a magnet. This leads me to why I felt the need to
post this. I learned recently that rare earth magnets have a
failing. Above a certain temperature they loose their magnetism and
that temperature is much lower than you might think. A little
higher and they lose their magnetism permanently. These temps are
below the melting temperature of lead. Now a mold rarely gets as
hot as lead. Even if you set it on top of the lead pot to preheat,
but it does get pretty hot. Hot enough that you have to wear gloves
to handle it safely. Maybe closer than you might like to
degmagnetizing temperature of the magnet.

I didn't research other magnets as I like the strong holding force
of even tiny rare earth (neodymium) magnets for these problematic
applications. I discovered that for a little more money there were
higher heat rated rare earth magnets. I check a couple sources.
MSC didn't have any in a size I wanted. McMaster had one size that
was useful. K&J had them much cheaper than McMaster, but they were
further away and only shipped UPS. I ordered from both McMaster and
K&J Magnetics.

I actually had two molds that I couldn't come up with any other
solution for. The first was done with the McMaster magnets and like
other magnets I have ordered they were a little under their
specified dimensions. They also did not seem to have a hard coating
like most rare earth mags I have bought in the past. I just glued
them in place with JB weld. The K&J magnets came in a few days
later, and I miced them. I took measurements on 2 or 3 out of each
pack. They were all within 0.0005" of target diameter, and about
the same for target length. They also had the nice shiny nickel
coating I am used to seeing. I machined tapered holes (.001 over
at the top to .001 under at the bottom) to press the magnets into
and they fit perfectly. I expect if you rapped the mold sharply on
the bench you could knock them free, but neodymium magnets are
pretty fragile. I didn't want to break them when pressing them in.

Another thing learned. I hope it helps somebody else.

If you were desperate enough you could run a piece of steel out the
side and slip a solenoid coil over it.
-jsw

"Jim Wilkins" wrote in message news
"Bob La Londe" wrote in message
news
I don't care for using magnets in molds. For the most part its
unnecessary. Once you get a feel for the mold it gets to be pretty easy to
slide a hook or a keeper into its slot. Even if you have to wear glasses
like I have had to for the last decade.

Sometimes though the only way to get a piece of hardware to stay in place
is with a magnet. This leads me to why I felt the need to post this. I
learned recently that rare earth magnets have a failing. Above a certain
temperature they loose their magnetism and that temperature is much lower
than you might think. A little higher and they lose their magnetism
permanently. These temps are below the melting temperature of lead. Now
a mold rarely gets as hot as lead. Even if you set it on top of the lead
pot to preheat, but it does get pretty hot. Hot enough that you have to
wear gloves to handle it safely. Maybe closer than you might like to
degmagnetizing temperature of the magnet.

I didn't research other magnets as I like the strong holding force of even
tiny rare earth (neodymium) magnets for these problematic applications. I
discovered that for a little more money there were higher heat rated rare
earth magnets. I check a couple sources. MSC didn't have any in a size I
wanted. McMaster had one size that was useful. K&J had them much cheaper
than McMaster, but they were further away and only shipped UPS. I ordered
from both McMaster and K&J Magnetics.

I actually had two molds that I couldn't come up with any other solution
for. The first was done with the McMaster magnets and like other magnets
I have ordered they were a little under their specified dimensions. They
also did not seem to have a hard coating like most rare earth mags I have
bought in the past. I just glued them in place with JB weld. The K&J
magnets came in a few days later, and I miced them. I took measurements
on 2 or 3 out of each pack. They were all within 0.0005" of target
diameter, and about the same for target length. They also had the nice
shiny nickel coating I am used to seeing. I machined tapered holes (.001
over at the top to .001 under at the bottom) to press the magnets into and
they fit perfectly. I expect if you rapped the mold sharply on the bench
you could knock them free, but neodymium magnets are pretty fragile. I
didn't want to break them when pressing them in.

Another thing learned. I hope it helps somebody else.

If you were desperate enough you could run a piece of steel out the
side and slip a solenoid coil over it.
-jsw

*** My first reaction was literally to laugh out loud, but of course you are
right. I had this visualization of some poor tackle maker wondering why his
jig mold looked like a miniature Russian EMP generator and why in the heck
he would have to plug it in to the wall. LOL.

On Tue, 31 Oct 2017 14:43:44 -0700, "Bob La Londe"
wrote:

"Jim Wilkins" wrote in message news
If you were desperate enough you could run a piece of steel out the
side and slip a solenoid coil over it.
-jsw

*** My first reaction was literally to laugh out loud, but of course you are
right. I had this visualization of some poor tackle maker wondering why his
jig mold looked like a miniature Russian EMP generator and why in the heck
he would have to plug it in to the wall. LOL.

That definitely hit me in the same way, Bob. Reading the pic you
painted right afterward sent me directly to the tissues.


Happy Halloween, you culturally appropriating racists.
https://www.washingtontimes.com/news...ct-halloween-/

--
The Road to Success...is always under construction.
--anon

"Larry Jaques" wrote in message
...
On Tue, 31 Oct 2017 14:43:44 -0700, "Bob La Londe"
wrote:

"Jim Wilkins" wrote in message news
If you were desperate enough you could run a piece of steel out the
side and slip a solenoid coil over it.
-jsw

*** My first reaction was literally to laugh out loud, but of course
you are
right. I had this visualization of some poor tackle maker wondering
why his
jig mold looked like a miniature Russian EMP generator and why in
the heck
he would have to plug it in to the wall. LOL.

That definitely hit me in the same way, Bob. Reading the pic you
painted right afterward sent me directly to the tissues.


Happy Halloween, you culturally appropriating racists.
https://www.washingtontimes.com/news...ct-halloween-/

Stop disrespecting undead-Americans and traditional Celtic religion
(witches) too.

On Tue, 31 Oct 2017 11:47:47 -0700, "Bob La Londe"
wrote:

I don't care for using magnets in molds. For the most part its unnecessary.
Once you get a feel for the mold it gets to be pretty easy to slide a hook
or a keeper into its slot. Even if you have to wear glasses like I have had
to for the last decade.

Sometimes though the only way to get a piece of hardware to stay in place is
with a magnet. This leads me to why I felt the need to post this. I
learned recently that rare earth magnets have a failing. Above a certain
temperature they loose their magnetism and that temperature is much lower
than you might think. A little higher and they lose their magnetism
permanently. These temps are below the melting temperature of lead. Now a
mold rarely gets as hot as lead. Even if you set it on top of the lead pot
to preheat, but it does get pretty hot. Hot enough that you have to wear
gloves to handle it safely. Maybe closer than you might like to
degmagnetizing temperature of the magnet.

I didn't research other magnets as I like the strong holding force of even
tiny rare earth (neodymium) magnets for these problematic applications. I
discovered that for a little more money there were higher heat rated rare
earth magnets. I check a couple sources. MSC didn't have any in a size I
wanted. McMaster had one size that was useful. K&J had them much cheaper
than McMaster, but they were further away and only shipped UPS. I ordered
from both McMaster and K&J Magnetics.

I actually had two molds that I couldn't come up with any other solution
for. The first was done with the McMaster magnets and like other magnets I
have ordered they were a little under their specified dimensions. They also
did not seem to have a hard coating like most rare earth mags I have bought
in the past. I just glued them in place with JB weld. The K&J magnets
came in a few days later, and I miced them. I took measurements on 2 or 3
out of each pack. They were all within 0.0005" of target diameter, and
about the same for target length. They also had the nice shiny nickel
coating I am used to seeing. I machined tapered holes (.001 over at the
top to .001 under at the bottom) to press the magnets into and they fit
perfectly. I expect if you rapped the mold sharply on the bench you could
knock them free, but neodymium magnets are pretty fragile. I didn't want to
break them when pressing them in.

Another thing learned. I hope it helps somebody else.

I once designed and built a custom four place magnetic lab stirrer
with electrically heated aluminum jackets for a sample workup. I
needed the samples at 200 C with uniform temperature.

Due to the temperature, I went with samarium cobalt magnets for the
drivers. I recall them being relatively inexpensive. They were
fragile. I mounted them almost entirely enclosed within aluminum
mounts.

Worked great through the thin ss baseplate and ss sample vessels.

Pete Keillor

On Wed, 1 Nov 2017 08:03:27 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Tue, 31 Oct 2017 14:43:44 -0700, "Bob La Londe"
wrote:

"Jim Wilkins" wrote in message news If you were desperate enough you could run a piece of steel out the
side and slip a solenoid coil over it.
-jsw

*** My first reaction was literally to laugh out loud, but of course
you are
right. I had this visualization of some poor tackle maker wondering
why his
jig mold looked like a miniature Russian EMP generator and why in
the heck
he would have to plug it in to the wall. LOL.

That definitely hit me in the same way, Bob. Reading the pic you
painted right afterward sent me directly to the tissues.


Happy Halloween, you culturally appropriating racists.
https://www.washingtontimes.com/news...ct-halloween-/

Stop disrespecting undead-Americans and traditional Celtic religion
(witches) too.

Speaking of the undead, I rented The Mummy and was aghast to find that
it was somewhat of a zombie movie, with not a single bare anything on
the gorgeous mummy queen goddess. Output from Hollywood has gotten
more and more dull as they go PC.

--
The Road to Success...is always under construction.
--anon

On Wed, 01 Nov 2017 06:17:37 -0700
Larry Jaques wrote:

Speaking of the undead, I rented The Mummy and was aghast to find that
it was somewhat of a zombie movie, with not a single bare anything on
the gorgeous mummy queen goddess. Output from Hollywood has gotten
more and more dull as they go PC.

Ya gotta check those ratings first. It was only PG-13...

For a low budget hoot check out this trailer for Machete:

https://www.youtube.com/watch?v=I16020r--oM

There was a sequel too, haven't gotten to it yet ;-)

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

"Larry Jaques" wrote in message
...
On Wed, 1 Nov 2017 08:03:27 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
. ..
On Tue, 31 Oct 2017 14:43:44 -0700, "Bob La Londe"

wrote:

"Jim Wilkins" wrote in message news If you were desperate enough you could run a piece of steel out
the
side and slip a solenoid coil over it.
-jsw

*** My first reaction was literally to laugh out loud, but of
course
you are
right. I had this visualization of some poor tackle maker
wondering
why his
jig mold looked like a miniature Russian EMP generator and why in
the heck
he would have to plug it in to the wall. LOL.

That definitely hit me in the same way, Bob. Reading the pic you
painted right afterward sent me directly to the tissues.


Happy Halloween, you culturally appropriating racists.
https://www.washingtontimes.com/news...ct-halloween-/

Stop disrespecting undead-Americans and traditional Celtic religion
(witches) too.

Speaking of the undead, I rented The Mummy and was aghast to find
that
it was somewhat of a zombie movie, with not a single bare anything
on
the gorgeous mummy queen goddess. Output from Hollywood has gotten
more and more dull as they go PC.


Egyptian queens don't age well:
https://news.artnet.com/app/news-upl...3-1200x785.jpg

https://mathildasanthropologyblog.fi...008/07/nef.jpg

On Wed, 1 Nov 2017 10:37:44 -0400, Leon Fisk
wrote:

On Wed, 01 Nov 2017 06:17:37 -0700
Larry Jaques wrote:

Speaking of the undead, I rented The Mummy and was aghast to find that
it was somewhat of a zombie movie, with not a single bare anything on
the gorgeous mummy queen goddess. Output from Hollywood has gotten
more and more dull as they go PC.

Ya gotta check those ratings first. It was only PG-13...

For a low budget hoot check out this trailer for Machete:

https://www.youtube.com/watch?v=I16020r--oM

There was a sequel too, haven't gotten to it yet ;-)

I saw the original, and it was a hoot. Bloody to the extreme, but
some lovely ladies wore nothing. The sequel trailer looked awful so I
passed on it.


--
The Road to Success...is always under construction.
--anon

On Wed, 1 Nov 2017 12:16:15 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Wed, 1 Nov 2017 08:03:27 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
...
On Tue, 31 Oct 2017 14:43:44 -0700, "Bob La Londe"

wrote:

"Jim Wilkins" wrote in message news If you were desperate enough you could run a piece of steel out
the
side and slip a solenoid coil over it.
-jsw

*** My first reaction was literally to laugh out loud, but of
course
you are
right. I had this visualization of some poor tackle maker
wondering
why his
jig mold looked like a miniature Russian EMP generator and why in
the heck
he would have to plug it in to the wall. LOL.

That definitely hit me in the same way, Bob. Reading the pic you
painted right afterward sent me directly to the tissues.


Happy Halloween, you culturally appropriating racists.
https://www.washingtontimes.com/news...ct-halloween-/

Stop disrespecting undead-Americans and traditional Celtic religion
(witches) too.

Speaking of the undead, I rented The Mummy and was aghast to find
that
it was somewhat of a zombie movie, with not a single bare anything
on
the gorgeous mummy queen goddess. Output from Hollywood has gotten
more and more dull as they go PC.


Egyptian queens don't age well:
https://news.artnet.com/app/news-upl...3-1200x785.jpg

https://mathildasanthropologyblog.fi...008/07/nef.jpg

Darned if you're not right.

--
The Road to Success...is always under construction.
--anon