trouble in paradise

So ive been off my printer for a while, when i got back to it, my prints where not the same quality as before. .so i got my tools and tinkered away . .mechanical side of the printer was good as gold . .maybe it was the bowden which i just recently switched to. ."to gain some z travel" . .with that as a suspect culprit, i changed back to the normal extruder config i was using . .still getting bad finished prints . .so when i was to change back to the bowden config . .then i realized a hadnt look at my hot end yet . .so took off the insulation tape . .low and beheld against me were broken off resistor leads . .weird though as i was still getting temp readings on the printer interface . So ill be givin' the old hot end an overhaul . .total accumulative time printing would be 45hrs or so . . .

Where was it stored when you weren't using it?

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Richmond, New Zealand
Thingiverse ~ YouTube

It was inside the house @ wired1


Got my hot end built again . . .heating and temp checks ok . . .havent printed with it yet . .something for tommorow . .if i get some time . . .

How did it go?

My hot end is out of action at the moment. I melted the heater resistor, and two replacements.
Vik Oliver suggested nichrome wire imbedded in furnace cement, and gave me some wire. Once I have sourced some furnace cement, I'll give it a go.

Also, if you are usung PLA, I hope you have stored it somewhere cool and dry. Someone did suggest heating in an oven at 50C for an hour or so to remove unwanted moisture, but I haven't been game to try it.

Its up and running again @ inquisistor

I was also looking at using nichrome wires, but used the resistor coz i couldnt source some fire cement at the time i was building . .what is the watt and ohms specs on the resistors you use ? What controller are you using on your 3d printer?

My hot end setup is 2x 5watt @ 5.6 ohms 5% tollerance and i use sanguino 1.3 as controller, the mosfet for the hot end runs warmer than the one for the heat bed but nothing a 60mm fan couldnt controll . .

I'm using Sanguinololu, the voltage across the hot end resistor measures 19 volts. The Huxley assembly page suggests a 6.8 ohm 3 watt resistor.
I went into Jaycar today to try and find the right resistor, but the only wire wound resistors they have are 5 watt, square and too large to fit the hole. I got some more nichrome wire and Bunnings had the high temperature cement, so I should have enough for several attempts.
Vik said that 4 ohms is enough and that the nichrome wire in the furnace cement can survive getting red hot. I'll let you know.

Got my hot end wound with about 50cm of nichrome wire imbedded in furnace cement. It reads about 7 ohm. Hooked it all up, and now I find that the thermistor isn't working. Maybe that's why my resistors blew.
I have had to chip some of the cement away to get the thermistor out. Some of the nichrome wire is exposed, but it still reads 7 ohm.
Tried it out on a 12 volt battery charger. Heated up nicely.

Now I need to source another thermistor. Any Ideas?

Pretty sure Vik sells them Diamondage

Edited 1 time(s). Last edit at 09/02/2012 04:06AM by Wired1.

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Richmond, New Zealand
Thingiverse ~ YouTube

You are probably right, since it was Vik's suggestion I'm trying with the nichrome wire. I didn't see what thermistors he used for his hot ends as they were buried deep in the cement.