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Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!
Andy_R

Compact Mk5 Extruder Heater Core

by Andy_R Feb 1, 2011

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I like that you are having a crack at the problem. There's a lot of experience to draw from in the thingiverse world, and this project encourages discussion from all quarters. Just what's needed. ;)

Nice thinking Andy...

But have you tried it...

Is it not a bit ......... slow..?
How long does it take to heat it up to... 220 °C...?

These resistors have a capacity of 7Watts each ..? a max of 28 watts total....?? i use 45 watts...on 2 25watts resistors....heats up to 235°C in 10 minutes...

And i i see your res
istors have a max of 200°C.... i don`t think they will last long.... but i may be wrong..

God luck anyway... if them resistors don`t last long maybe it exists resistors in the same size with better specifications...

And again... good idea... i have been thinking of something like this too... on
ly using heat elements from some solder irons.... haven`t tried it yet tho..... ;)

I had a test resistor epoxied into an aluminium block and ran that to 265
°C at which point the epoxy started to smoke a bit, but the resistor still works OK.

On the heater block as built, it takes me about 3mins to reach 210°C or so from cold (18-20°C). I have four 10ohm resistors in parallel, which gives a total resistance of 2.5ohms - that's nearly 60W power! Th
e 7W spec is for the resistors in "normal use" - i.e. allowing for their normal heat rejection to the surrounding air as if it were populated on a PCB.

We shall see how long it lasts...

Correct me if I'm wrong... but is not the wattage rating on resistors a rating for thermal disapation, not power consumption?

We are generally abusing the resistors we use anyway, and the top end of the thermal rating is typically a time limited rating (and short enough to be less than we use). The normal MK5 resistors are 10w are they not? (mines all wrapped in insulation). The main requirement is that the resistance is low enough that we can jam enough current through.

I think that vitrious enamel resistors might be a better bet as they have far higher thermal ratings. If I had a drill press I'd be all over this!
Maybe I need to make that dremel mount I have been thinking about for so long... see how long my dremel bits last!
Mmmm.. cupcake making upgrade parts
is always cool!