Smoking Hot End

[Patrick23]

I just recently purchased a Rostock a few weeks ago. I'm now at the part of the build where I heat up the hot end for the first time. As the temperature rises I noticed that smoke starts to come out of the hot end. It's hard to tell exactly where, but from searching the forums it seems the resistors could be the issue. I had difficulty getting the aluminum foil wrapped tight enough to get a snug fit in the hot end. I tried rewrapping them and thought I had done a better job, but I still get smoke. Has anyone else had this happen to their Rostock?

[Jimustanguitar]

I noticed this a little bit with mine too. It's kind of like heating up a new soldering iron or turning on the furnace for the first time every season, there will be a little bit of burnoff. This is probably due to skin oil, machining coolant, silicone solvents, etc on the new hotend. You should only notice this the first time.

Be cautious that you're not actually burning something, but don't worry if you get a few wisps the first time.

[grabredemeyer]

If this is your first time turning heat on without having done PID tuning, I would recommend killing the heat once you know the hot end is indeed heating up as noted in the manual. If you do not turn it off, it will continue heating since there has not been PID tuning done yet to the point that you would see smoke and possibly even crack out a part of the hot end. I figured you probably aren't making this mistake, but wanted to note it just in case. Once PID tuning is done, it should be no problem....that is if you haven't done it already.

[Patrick23]

Thanks! I start the PID tuning, but once the temperature gets to about 140C, I start to notice smoke. I've tried this twice and both times I've had smoke, so I've cut the power before letting it complete. Power to the hot end was only applied for maybe 45 seconds each time. I'm hoping to give it another go tonight to see if maybe it's just chemicals burning off.

[626Pilot]

Make sure that the thermistor is securely cemented into the heat block, and that it hasn't been yanked out after the fact. 140C is not hot enough to melt anything, but you need to be sure it really is 140C.

[Jimustanguitar]

If you have a multimeter with a thermocouple (a lot of us have the $20 one from harbor freight) you can see if your thermistor is reading correctly or not. That's the for sure way to be safe.

You could also manually spin the extruder and see when filament starts oozing. Usually this is between 160 and 180.

[johnoly99]

If you used the RTV suggested, it's normal to see a little bit of smoke for a few minutes. I'd recommend setting the hotend temp to 140 or 150, and let it sit there for 5 mins or so, then let it cool down to room temp, and then run the PID autotuning. The oils from machining and the silicone will give off a bit of smoke the first fire up, but go away after just a few mins.

You shouldn't have to worry about the PID tuning at that temp, as it won't overshoot enough to worry about

[626Pilot]

Maybe this will help you be a little less skittish. It's a jet engine burning off oil left over from being manufactured and stored.

[youtube]http://www.youtube.com/watch?v=EDc8o_h-dn0[/youtube]

See? Nothing to worry about.

[Patrick23]

That video definitely eases my fears .

I was able to use a thermocouple at work and the thermistor is reading the temperature correctly. I'm still seeing smoke, but now I have a broken thermistor to replace (unrelated to the smoke, I over stressed the leads when working on the hot end). Which thermistor (6K or 100K) from SeeMeCNC should I be getting to replace the hot end thermistor with?

[Eaglezsoar]

That video definitely eases my fears .

I was able to use a thermocouple at work and the thermistor is reading the temperature correctly. I'm still seeing smoke, but now I have a broken thermistor to replace (unrelated to the smoke, I over stressed the leads when working on the hot end). Which thermistor (6K or 100K) from SeeMeCNC should I be getting to replace the hot end thermistor with?

You need the 100K thermistor.

[Durandal]

I would recommend the screw in thermistor from RP ONE labs on ebay, tap the head with an M2 thread and never worry about the leads on your head again.

[barry99705]

Maybe this will help you be a little less skittish. It's a jet engine burning off oil left over from being manufactured and stored.

[youtube]http://www.youtube.com/watch?v=EDc8o_h-dn0[/youtube]

See? Nothing to worry about.

I've never seen any of our engines do that!!!

[lordbinky]

Think of the guys who just go everything cleaned up and then see that.

[geneb]

It's an M3 thread.

Video of the process here: http://www.youtube.com/watch?v=xvXKt3xDt4E

g.

[cope413]

It's an M3 thread.

Video of the process here: http://www.youtube.com/watch?v=xvXKt3xDt4E

g.

You can fit an m3 screw into m2 threading. Just put some muscle into it. It's only soft aluminum

[barry99705]

It's an M3 thread.

Video of the process here: http://www.youtube.com/watch?v=xvXKt3xDt4E

g.

You can fit an m3 screw into m2 threading. Just put some muscle into it. It's only soft aluminum

As a bonus, you don't have to use threadlocker!!

Think of the guys who just go everything cleaned up and then see that.

I'm thinking the heat couldn't have been good to the composites in the flaps. Yea, the wash rack guys would have been pissed! It's a pain in the ass to wash a large aircraft, adding soot to the mix would make it worse.

[626Pilot]

It's a pain in the ass to wash a large aircraft, adding soot to the mix would make it worse.

They're only fun to wash when they're yours.