I have successfully repaired the plastic extruder of my repstrap 3d printer. I had to buy a cheap drill press in order to process the raw ptfe and the brass barrel. It seems to be really hard to drill straight though the brass barrel without a drill press (or maybe my drill wasn't good...).

This time I wanted to make sure that the brass barrel couldn't slip out of the thermal barrier again, so I secured the brass barrel in place with a nut and a square piece of ptfe, which is attached to the wood frame with two screws.

As you can see on the picture below I printed a complete set of parts for Wade's extruder (www.thingiverse.com/thing:1794). 

The print quality is still not perfect but I think it is usable and sufficient for printing the RepRap Mendel parts. I started printing Mendel parts already. The only problem remaining is warping, I don't think I can avoid this without a heated printing bed. But it is not that bad yet, so I hope to get along without a heated bed untill I have a working Mendel.

3d printer in action from Gerrit Wyen on Vimeo.