C
Computer Nerd Kev
Guest
I've wanted to (and in a few cases tried to) make small heating elements
for various things in the past, but I've never worked out a good way to
keep the heating elements in place and stop them shorting out.
I've seen the ceramic-like (to the touch) potting compound used in things
like soldering iron elements, which I presume to be this sort of stuff:
http://measuretech.com.au/potting-compounds/91-durapot-810-highly-thermally-conductive-potting-compound.html
But, well, $335.17 for one Pint!
I haven't had much luck finding other prices, but that's a long way
off the sort of money I'd want to pay. Indeed all their potting
compounds are in the same price range:
http://measuretech.com.au/39-potting-compounds
Epoxy can be rated for high temperatures, between 200-300C, but being
a poor thermal conductor, I'd be worried about cooking the epoxy from
the inside before the surrounding metal heats up.
Nichrome wire isn't hard to get a hold of, so is it unreasonable to
expect potting compound or something equivalent to be likewise? Have
I been missing some obvious solution?
Details you might not need to read follow:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
PAST ATTEMPTS:
I've previously tried weaving Nichrome wire in Kapton tape on top of
a flat solid base, but the adheasive of the Kapton weakens at higher
temperatures and it didn't prove a very solid solution to keeping the
wires from shorting out.
I also had a go at using VeroBoard with tracks soldered together. This
works at lower temperatures (under about 80C, maybe a bit less), but
as it gets hotter it tends to shrivel up and expel a strong vapour
that also coats nearby objects in a sticky yellowish substance and
causes nearby objects, clothes, and humans to stink for days. I
concluded at the time that my target temperature of 160C wansn't going
to work, and that I don't want to know the health implications of the
experiment.
CURRENT ATTEMPT:
I'm still working on a good method for desoldering ICs from circuit
boards (you might remember my topic on the matter from about a year
ago). So far: hair straighteners can't go hot enough (though can work
on leaded solder and single sided boards), blowtorching the back of
a board and hitting it against something doesn't force the ICs out,
even with their pins straightened on the bottom, and it's also easy
to cook parts when you get desperate (that was yesterday's attempt,
might try a more subtle flame in the future when I get one that will
stay alight), and I'm still no good with a solder sucker.
Now I'm looking at either building a vacuume desoldering iron (as
was my first plan last time, but I'm now tempted to do it completely
from scratch as I've got small a thick walled copper tube that might
be perfect), or a large heated block of copper the width of an IC
that can melt the solder on one whole side of a chip at once.
I think I've got a way to make the heating element in the
block-o-copper solution with just Kapton tape for electrical insulation
from the Nicrome heating wires. I might test the method first by just
heating it with my blowtorch.
However I can't work out a way that seems reliable by which to build a
heating element for the vacuume desoldering iron. I really need to be
able to encase it in something. Power resistors, besides being too
large and difficult to mount, don't seem to be rated up to the required
temperature.
--
__ __
#_ < |\| |< _#
for various things in the past, but I've never worked out a good way to
keep the heating elements in place and stop them shorting out.
I've seen the ceramic-like (to the touch) potting compound used in things
like soldering iron elements, which I presume to be this sort of stuff:
http://measuretech.com.au/potting-compounds/91-durapot-810-highly-thermally-conductive-potting-compound.html
But, well, $335.17 for one Pint!
I haven't had much luck finding other prices, but that's a long way
off the sort of money I'd want to pay. Indeed all their potting
compounds are in the same price range:
http://measuretech.com.au/39-potting-compounds
Epoxy can be rated for high temperatures, between 200-300C, but being
a poor thermal conductor, I'd be worried about cooking the epoxy from
the inside before the surrounding metal heats up.
Nichrome wire isn't hard to get a hold of, so is it unreasonable to
expect potting compound or something equivalent to be likewise? Have
I been missing some obvious solution?
Details you might not need to read follow:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
PAST ATTEMPTS:
I've previously tried weaving Nichrome wire in Kapton tape on top of
a flat solid base, but the adheasive of the Kapton weakens at higher
temperatures and it didn't prove a very solid solution to keeping the
wires from shorting out.
I also had a go at using VeroBoard with tracks soldered together. This
works at lower temperatures (under about 80C, maybe a bit less), but
as it gets hotter it tends to shrivel up and expel a strong vapour
that also coats nearby objects in a sticky yellowish substance and
causes nearby objects, clothes, and humans to stink for days. I
concluded at the time that my target temperature of 160C wansn't going
to work, and that I don't want to know the health implications of the
experiment.
CURRENT ATTEMPT:
I'm still working on a good method for desoldering ICs from circuit
boards (you might remember my topic on the matter from about a year
ago). So far: hair straighteners can't go hot enough (though can work
on leaded solder and single sided boards), blowtorching the back of
a board and hitting it against something doesn't force the ICs out,
even with their pins straightened on the bottom, and it's also easy
to cook parts when you get desperate (that was yesterday's attempt,
might try a more subtle flame in the future when I get one that will
stay alight), and I'm still no good with a solder sucker.
Now I'm looking at either building a vacuume desoldering iron (as
was my first plan last time, but I'm now tempted to do it completely
from scratch as I've got small a thick walled copper tube that might
be perfect), or a large heated block of copper the width of an IC
that can melt the solder on one whole side of a chip at once.
I think I've got a way to make the heating element in the
block-o-copper solution with just Kapton tape for electrical insulation
from the Nicrome heating wires. I might test the method first by just
heating it with my blowtorch.
However I can't work out a way that seems reliable by which to build a
heating element for the vacuume desoldering iron. I really need to be
able to encase it in something. Power resistors, besides being too
large and difficult to mount, don't seem to be rated up to the required
temperature.
--
__ __
#_ < |\| |< _#