Simple question: how do you reinsulate the MakerBot Smart Extruders?

Backstory: I work at the library. We've recently replaced the MakerBot (extruder connection issues followed by software incompatibility) with a Prusa.

As a new hire, I'm obsessed with the 3D printers. I'm trying to make it my mission to get the MakerBot working again, just so we can have two printers running.

It takes quite the request chain to get materials in and I had some plumbing tape on hand, so I tried to wrap it with that, per this thread. It's not going too well because of the housing around the Smart Extruder, which I cannot figure out to remove (easily and/or without voiding the warranty and taking it completely apart).

I imagine even with the cotton + Kapton tape, you'd need better access to the hotend than the housing allows.

Any help is appreciated!


2 Answers 2


I recently wrapped a LOT of hot PLA around my print head and, as a result, had to remove the kapton tape and the fibreglass insulation that came with it.

I was reluctant to use fibreglass because of the tissue embedding hazard and the lung hazard (especially on what is effectively an indoor appliance) and kapton tape is very hard to find in Australia.

After some research, I wrapped the print head in 100% wool felt that I bought from a fabric store (be very careful, as most craft felt nowadays is either acrylic, polyester or a poly/wool blend) and then bound it all up with teflon thread tape (plumber's thread tape).

Cotton has a scorch temperature of 150 to 200°C, while wool won't scorch until 500 to 600°C, and the teflon tape can handle temperatures between 200 to 300°C.

Did it work? Well I can now put my finger on the outside of the tape after the element has been at 200°C for 10 minutes, and only feel a little warmth. The print head heats up twice as fast, and I can run my massively oversized print cooling fan at 40% rather than the 10% I could use before. There is no odor of anything cooking off either. Success!

  • $\begingroup$ The flat pieces of felt? I might try that! I've been afraid to Crack open the extruder housing. Did you have to do that to re-wrap yours? $\endgroup$
    – Stacie
    Jul 9, 2018 at 1:17
  • $\begingroup$ I just grabbed a 1/2 metre of felt from the fabric shop, cut a strip out using scissors and then snipped a hole for the extruder tube. Then wrapped the felt around the aluminium block, snipped another hole to let the nozzle through, then trimmed it to length. Then I just grabbed the thread tape and kept wrapping until the extruder block was one plastic pink slab, with the nozzle and the tube poking through. $\endgroup$ Jul 11, 2018 at 9:29
  • $\begingroup$ I didn't NEED to pull the extruder apart completely. I was able to unscrew the nozzle/block and tube arrangement from the stepper array. On the Geeetech, this is easy to do if you first unclip the stepper's cables, remove the fan from the stepper, then unscrew the whole array from the x-axis assembly. Remove the nuts from the extruder tube, and you're good to wrap. However, I DID pull the nozzle and tube from the aluminium block as I needed to blowtorch a LOT of plastic off and out of them. I had to replace the teflon tube after, but it needed replacing any way. $\endgroup$ Jul 11, 2018 at 9:40
  • $\begingroup$ WHOOPS. On further experience, I can't recommend this just yet. I DO get a distinct hot wool smell on very long prints. Let me get back to people about how well this works over a longer time. $\endgroup$ Jul 12, 2018 at 14:30

Strictly speaking, you do not require the insulation to be there. It is supposed to keep some of the heat contained in the core to allow more heat to be available for the filament to melt (basically higher print speeds and less chance of burning your fingers :) ).

If I go to the Makerbot website and look at the video

Smart Extruder+ - 3D Printer Extruder - 3D Printer PLA Extruder

at 1:37, you'll see that the hot end is wrapped in cotton and Kapton tape. Like the stuff that is cheap and easy to buy:

enter image description here

and that the casing cover is removable, so you should be able to open it to insert new cotton. Why worry about voiding warranty? You can gain a working printer for a few bucks or bite the bullet and buy a new Makerbot Smart Extruder. I guess if you had warranty you could already have it replaced by now.

  • $\begingroup$ I do see the wrapped hot ends by themselves. All the information I've seen says opening the case voids the warranty and is something that can only be done by MakerBot? We got the Smart Extruder+ just before I started in March, but we don't have the service plan on them. I haven't had much luck finding information on the MakerBot! (And I'd thought the Prusa was a pain.) $\endgroup$
    – Stacie
    Jul 9, 2018 at 1:15
  • $\begingroup$ If you're not satisfied, claim repair under warranty if it is a factory problem? Else, figure out to open the cartridge, maybe a local technician (e.g. one doing electronic/phone repairs) can be asked to help out. $\endgroup$
    – 0scar
    Jul 9, 2018 at 7:35

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