Heater idea

There have been some tests with using wire wound resistors as the heater element, but most that I have observed used a machined aluminium block to transfer the heat from the resistor to the barrel.

How about using a simple ring crimp, such as

Ring crimp

Thanks for reading

I'd be surprised if a ring crimp (or even several) would have enough thermal conductivity to move the heat of the resistor to the heater barrel. The machined aluminum completely surrounds the resistor and the heater barrel. Aluminum foil packed around the resistor is used to increase the thermal conductivity between the resistor and the block.

If you don't have the means to machine aluminum you might be able to get a similar effect by wrapping the heater barrel with several layers of aluminum foil, pressing the resistor against the foil, and wrapping more aluminum foil around the whole thing. It won't conduct heat as well as solid aluminum but might be good enough.