Retraction and deretraction (priming) problems

[schafe 3]

Deretraction - is that a word?? I think I read priming is the proper term.

For some time I have been having problems with the retract/prime process. I have largely ignored it until recently when I started printing the P-38 Lightning from 3D Lab Print. With that model it is very important to have good layer adhesion.

The problem I have is the retract step leaves some material oozing out of the nozzle. This results in strings and blobs deposited in my print - not a big deal other than added weight. On the prime step, there seems to be a little bit of material missing and I get small blank spots where the filament has not fully primed. (Possibly mathematically not accounting for the material that oozed out of the nozzle???)

I have tried various retraction settings with little success. Speed does not seem to change anything and longer distances seems to make the prime problem worse.

I have noticed the bowden tube moves up and down in the print head during the retract step. I am going to experiment with ways to hold it firmly in place - maybe adding more of the clips that hold the "tube pinching device" in place.

I think I read once about an over prime value that some slicers use to make sure material is fully primed in the nozzle to account for the amount that oozes out. I am using Cura 15.02.1. Is there some way to over prime the nozzle??

Thanks in advance for the great help. I have always gotten good advice.