Insulate hotend on Makerbot Smart Extruder
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!