OK - I shaved down the other side of the resistor, but the end cap of the resistor is starting to show through and it doesn't quite fit in the barrel yet. I'll leave it up to Jake to take off the final layers if he dares - I'm worried we might be getting some shorts against the heater barrel though...

The alternative approach would be to buy a spare heater block (still available from Lulzbot for $15), and ream out the heater opening until the resistor fits. Not sure that's any easier to get a good fit though. Let me know if you like that idea, and I'll order the heater block.


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On Wed, Jan 17, 2018 at 6:25 PM, Patrik D'haeseleer <patrikd@gmail.com> wrote:
Sorry for trying to be helpful, but I don't think you could expect me to magically know those details. It just seemed better to use the Lulzbot resistor that you listed in your first email.


PS: the resistor recommended by Lulzbot is available on Digi-Key for $1.50 - might not help if it's the wrong resistance tho.

On Wed, Jan 17, 2018 at 3:48 PM, Jake <jake@spaz.org> wrote:
Patrik if we don't glue it in, it won't make thermal contact with the aluminum
block and will burn out.  Thermal paste gets squeezed out when the resistor
heats up and expands and then you end up with a gap and the resistor burns out.

We already went down the road with the Lulzbot resistor that is out of stock,
permanently.  It's also the wrong resistance, and the software patch to
compensate for that fact doesn't work.  I carefully chose this resistor value
(8 ohms) and the thermally conductive epoxy that I want to use to glue it in.

if you want to take over this project go ahead, but sowing doubt and
uncertainty will just leave us with no 3D printer for another three years.


On Wed, 17 Jan 2018, Patrik D'haeseleer wrote:

On Wed, Jan 17, 2018 at 4:04 AM, Jake <jake@spaz.org> wrote:

If someone gets the resistor shaved to fit in there, i'll bring in the
special two-part thermal bonding epoxy and glue it in, and then i'll hook up
the wires and we'll have a 3D printer again.

Don't glue it in place with epoxy, or you'll have to drill it out when it
burns out again. It should be a tight enough fit to hold in place by itself,
no? I would expect regular thermal paste to conducts heat better than the
epoxy anyway...


PS: the replacement resistor that Lulzbot sells is only $3.50, and I would
expect that one to fit the hole like a glove. They seem to be out of stock
right now though...