MK8 head + Bowden

I wanted to create a "bowden feed" using a makerbot MK8 filament drive and j-head hot end. This is for my experimental mandel.

The problem that I am having is that there is too much back pressure. I am using PTFE tubing and the path is not that aggressive.

Is there enough force in the MK8 to do something like this?

Could the problem be in the j-head hot end?

is this with 3mm or 1.75mm feedstock. i am assuming it is 1.75mm feedstock. do you mean you are having slippage, or having tubing stretch or pop off, what do you mean?


there are several issues with the hot to cold transition of hot ends when it comes to Bowden design. many working designs use a longer hot zone to reduce the amount of pressure as the feedstock is properly heated and soft when it is at the nozzle end. what flow rates are you having issues with and what nozzle size are you using?

Is there a complete write up somewhere on a working hot end for a Bowden extruder? Dimensions would be great .

I am using 1.75mm PLA and it is a 1.75mm J head.

The tube wants to pop off but it can not because of the press-fit hardware that is on the extruder and the hot end.

I am having trouble with all flow rates. It happens all the way down to 10mm/min