It is an Isolator by design…Aluminum would NOT be thermally isolating, it is VERY thermally conductive. PEEK is thermally isolating and can handle normal 3D printing temperatures.
There are machinable ceramics out there that could possibly be used instead of PEEK, and could probably handle higher temps. You could get a local machine shop to machine one for you. Or there are 3D printing companies that will 3D print parts in ceramic too (shapeways comes to mind). But I am not sure if the threads would turn out OK on a 3D printed ceramic.
Thanks for the tips! I will see if I can’t find a ceramic piece, I know it can withstand high temperatures. Until then I’ll be ordering replacement components and defintely using a fan!
What do you guys think about plaster of paris/cement mixture? Maybe mixed with some crushed perilite. THis is a high heat resistant material that I used to make a foundry to melt aluminum it. It would be light weight and easy to reproduce as well as virtually disposable and very cheap.
With the plaster I could cast the threads right in, then unscrew the hotend and bake to set! Or bake with it inside.
It would, however, be brittle, thus the cement to give it more rigidity.
There is some pressure created in the hot end during plastic extrusion. I am not sure how much, but it might be enough to break a plaster part. especially if the nozzle hits something.
If the PEEK melted, then the temperature got too high, and it is not the fault of the PEEK…just replace it and make sure it does not get too high again.
Keep in mind that there is 18% shrinkage once machined ceramic is fired. It is machined in the uncured state, then fired. It is also fairly expensive, but the best candidate I’ve come up with to date.