I found a piece of insulation material after searching the entire building. It's glassfiber with a sheet of aluminiumfoil. After wrapping it around the barrel I was curious how hot the barrel could get.
So I turned up the amps to 2.2 A at 24 volts. At 380 degrees celsius it was still climbing but I thought that was hot enough because some smoke was coming out of it and I don't trust the Celeron at these high temperatures.
I started experimenting with extruding HDPE and ABS, it works. Now the tweaking starts to get an optimal flow of material.
The Celeron turns out to be a very good solution. It's very easy to work with, it handles a bit like wood. When you turn it on a lathe I do advice to keep a vacuumcleaner next to it to prevent the machine from getting covered in a layer of yellow dust.
The thermalcouple reeds a temperature around 160 degrees celsius IN the material, just under the surface where the heaterbarrel (260 C) is attached. So I would stop spending money on PEEK, Celeron is cheaper and stiffer. It is possible to cut a thread but with frequent loosening and fastening I would advise to use metal inserts.
Some more good luck came to me today in the discovery of a stack of various thermalcouples. The shipment is dated from 1983 but I don't really care as long as they work...! After that I found a 30V/3A powersuply that works better than the one I was using.
It turns out that when you know where to look (usually places where no one ever comes) you will find lots of 'forgotten' equipment, parts and tools that come in handy in some way.
Now my weekend starts...I can't wait till monday...
Beware fake multi-meter leads
10 months ago