Hotend assembly (pro version)

Discussion in 'Build Help' started by Alex Stevenson, Apr 10, 2016.

  1. Alex Stevenson

    Alex Stevenson Well-Known Member

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    I'm getting to the point in the BigBox assembly where I'm putting together the hot end. The application of thermal compound seemed a little vague, so I did some googling on how I should best apply it. The results I got seemed to be a confusing mix of "thermal compound should not be used on a hot-end" and no real advice.

    I finally found this:
    http://wiki.e3d-online.com/wiki/E3D-v6_Assembly#Thermal_Compound

    Which mentions why the compound is now included. I don't want to add too much, and if it's not necessary, then I think I'd rather not use it.

    Can anyone advise on the pros-and-cons of using the thermal compound, and give more detail on how much I should use; like I said, I think I'd rather use as little as I need.

    Also, generally regarding the assembly, I also watched Tom's guide here:


    I know this is a stupid question, but am I correct in assuming that the process with the thermistor is now not applicable, and entirely replaced with the PT100?

    Thanks (and sorry for dumb questions - I'm most anxious about getting the hot-end bit right, even more so than the mains wiring...)
     
  2. Alex9779

    Alex9779 Moderator
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    Use it, if you applied too much you would notice because it will squeeze out...

    Yep the PT100 replaces the thermistor. Easier to install, more durable, can measure higher temperatures so that you can print high temp materials... Stock firmware sets the maximum hotend temp to 320° C.
     
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  3. Old_Tafr

    Old_Tafr Well-Known Member

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    The thermal paste is only applied to the screw thread of the thermal break that screws into to the heatsink.

    On this page

    http://wiki.e3d-online.com/wiki/BigBox_Printer_main_assemblies:_Step_By_Step_Assembly_Process

    This section

    Assembly of the E3D HotEnd

    under....

    "V6 only"

    "Apply the thermal paste to the Heat-Break and screw it into the Heat-Sink. "

    PS

    Using Google's Chrome browser and using CTRL-F to find say "break" not only finds all instances but shows where they are on the right by the scroll bar.
     
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  4. Alex Stevenson

    Alex Stevenson Well-Known Member

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    Thanks @Old_Tafr, I saw that. I meant more precisely how much and how best to apply it. I'm more used to applying it to CPUs, where if you don't get it even, then it can cause fairly critical failures - I couldn't seem to find any videos or pictures to clarify this part of the process.
     
  5. Alex Stevenson

    Alex Stevenson Well-Known Member

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    Thanks @Alex9779 that helps a lot. At least I won't worry about applying too much now... (although there's a fairly small sachet, so I don't want to waste it if I get it wrong).
     
  6. Miasmictruth

    Miasmictruth Well-Known Member

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  7. jet

    jet Well-Known Member

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    I received two hotends with my BigBox V1.1, one had paste and the other didn't. Should I share the one packet between the two hotends? I also have some of the silicone-based heatsink compound we use with CPUs and Peltier coolers, but I don't know it's max temperature.
     
  8. Alex9779

    Alex9779 Moderator
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    One of those packets was enough to for four hotends for me...
    But every generic heats sink compound should work. I use one now I have left over from my last CPU installation...
     
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  9. Miasmictruth

    Miasmictruth Well-Known Member

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    I thought you needed something for high temps as the threads near the base of the heatsink gets hotter then a CPU, beyond the intended range for average thermal compounds, or am I confusing something else it was a while ago I read that.


    *** Edit: On the other hand looking over the V6 documentation I see nothing about special thermal compound, maybe that was just an opinion I read somewhere once upon a time.
     
  10. Alex9779

    Alex9779 Moderator
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    Maybe someone can measure... @Rob Heinzonly seems to have tools to do that.
     
  11. mike01hu

    mike01hu Well-Known Member

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    The heatsink compound is only used on the thread that is inside the heatsink not the head, you don't want good thermal conductivity in the bottom of the heat break, that's why its called a heat break:rolleyes:
     
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  12. Alex9779

    Alex9779 Moderator
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    That's exactly the point, you want to stay the heat in the heater block, only the heat going up the heatbreak, which you actually do not want at all but you have to mount the part somewhere, should then get into the heatsink with as few as thermal resistance as you can achieve. Thats why you only apply it to the upper end...
     
  13. jet

    jet Well-Known Member

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    Thanks -- I understand where it goes, I was just using "hot end" to describe the kit. One tube was plenty for two units.
     

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