Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone
 
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Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone  

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EsotericMaker
(@esotericmaker)
Trusted Member
Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone

I just needed to replace my MK3S+ heater cartridge because somehow in removing a nozzle (for the first time), I must have damaged the wires where they enter the cartridge causing them to short out.

Looking at the wire entry point, it is clear that this is a weak point since the insulation ends there and the wires are already spaced very close together.

What if I made a PLA cylindrical mold to fit around the end of the heater cartridge with say a diameter about 4mm larger than the cylinder and extending out say 10mm. I could then fill the cavity either with:

  • High temperature epoxy - more ridgid and maybe more protective
  • High temperature silicone - more flexible but maybe less protective though would still offer some strain relief and insulation between the wire ends - also might help protect against "blobs" (or at least they could be sacrificial)

JB Weld High Heat is borderline as it is rated up to 550 deg F (287 deg C) and is not conductive (unlike the Extreme Heat version) - I assume that the cartridge must get a little hotter than the heatblock so when printing things like PC blend at 270, you may be around 287 on the cartridge...

Any thoughts?

Posted : 01/02/2023 6:49 pm
Hello
(@hello)
Noble Member
RE: Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone

Sounds good but may want to print in a stronger material 

Please help me out by downloading a model it's free and easy but really helps me out https://www.printables.com/@Hello_474427/models

Posted : 01/02/2023 6:52 pm
Hello
(@hello)
Noble Member
RE: Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone

I was thinking heat shrink around wires

Please help me out by downloading a model it's free and easy but really helps me out https://www.printables.com/@Hello_474427/models

Posted : 01/02/2023 6:53 pm
EsotericMaker
(@esotericmaker)
Trusted Member
Topic starter answered:
RE: Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone

The PLA would just be for a mold and since it has such a low melting point (while by definition the epoxy/silicone and heater cartridge tolerate much hotter temperatures), it should be very easy to release the mold from the epoxy by just melting/softening it

Posted : 01/02/2023 6:55 pm
Hello
(@hello)
Noble Member
RE: Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone

Oh yes good idea

Please help me out by downloading a model it's free and easy but really helps me out https://www.printables.com/@Hello_474427/models

Posted : 01/02/2023 6:58 pm
EsotericMaker
(@esotericmaker)
Trusted Member
Topic starter answered:
RE: Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone

Thought of that but:

Shrink temperature of FEP is 177°C (350°F) Melt Temperature of FEP is 275°C to 295°C (525°F to 563°F)

Even the so-called high heat shrink tubing on Amazon cites a maximum working temperate of 250 F (not centigrade)

Posted : 01/02/2023 6:59 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone
Posted by: @esotericmaker

The PLA would just be for a mold and since it has such a low melting point (while by definition the epoxy/silicone and heater cartridge tolerate much hotter temperatures), it should be very easy to release the mold from the epoxy by just melting/softening it

I agree. However, to be on the safe side, I would use high-temperature silicone as filling material (up to 600 degrees C.).

wbr,

Karl

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.

Posted : 01/02/2023 7:13 pm
EsotericMaker
(@esotericmaker)
Trusted Member
Topic starter answered:
RE: Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone

Meanwhile as a temporary measure, I put a (careful) dab of high temperature RTV silicone where the wires join the heater cartridge. At a minimum, it will provide some electrical insulation so that I don't inadvertently short out the terminals when changing a nozzle.

At best, it will provide a (little) extra support and strain relief as well as preventing the wires from touching if/when the insulation pulls back a little from the cartridge.

Can't see any downside to this...

Posted : 01/02/2023 10:34 pm
rdpeder59
(@rdpeder59)
New Member
RE: Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone

How did this work for you?  I don't like the sharp 90 degree bend that is needed to put the heater in from that side.  In addition to doing the mod you proposed, I was thinking about putting the new heater in from the other side and doing a more gradual bend after the silicone dries.  

Posted : 11/07/2023 4:55 pm
EsotericMaker
(@esotericmaker)
Trusted Member
Topic starter answered:
RE: Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone

 

Posted by: @rdpeder59

How did this work for you?  I don't like the sharp 90 degree bend that is needed to put the heater in from that side.  In addition to doing the mod you proposed, I was thinking about putting the new heater in from the other side and doing a more gradual bend after the silicone dries.  

Worked well so far...

Posted : 11/07/2023 6:02 pm
rdpeder59
(@rdpeder59)
New Member
RE: Mod heater cartridge to protect wire connection by encasing in either high temperature epoxy or silicone

Thanks!  I'll proceed with silicone.

 

Posted : 11/07/2023 6:35 pm
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