I was pointing out that I know how to set a magnet in aluminum and I do
it as part of fairly common processes in my shop. Some of those items
experience quite a lot more thermal range than the average shop
environment casting parts from media that ranges from 350F to 850F. The
magnet itself typically does not experience those temps directly (It
would lose its magnetism), but in use experiences a thermal range as the
aluminum dissipates heat. I really don't think the heat range of from
maybe 30F (worst possible case if I left the doors open at night here in
the desert) to 130-140F (when the doors are closed and its a hot summer
day) will cause an issue in a short period of years. I do believe that
impacts will cause the magnets to break and crumble because I have seen
it happen. I can simpley set two on my desk and let them pull together
to see that.
FYI: I buy the higher thermal rating magnets from K&J Magnetics. They
can still shatter if impacted, but they keep their magnetism longer in
thermal cycling environments.
I am quite aware that you were referring to two different things. I
even spoke about the two different things separately. Iron in regard to
bending the magnetic lines of force, and weakening the effective
magnetic field, and rubber due to its propensity to flex and even
sometimes flow under various forces. I was not so confused to believe
that the rubber and the steel (mostly iron) were the same part.
I even acknowledge your overall idea, and commented more that I needed
to investigate or was uncertain for those reasons about the exact
application in practice.
I go one step further and note that its possible that even if the rubber
does flex friction of the back body may prevent it from being an issue.
Still I would go with a very high shore hardness if I implemented a
rubber thermal growth compensation mechanism. Your ideas do merit
consideration. Just pointing out the things that appear obvious to me.