[protocolture]

Yeah I was thinking multi head for this, wider nozzle for dropping material in the gaps. Especially if you could find something lower temp than the other walls.

That said, maybe an acetone drip or something in a strength channel to try and bond it.

Actually what I do (and I think is pretty common) is just stopping the print from time to time and filling the outer infill channels with wood glue and sand. Sometimes wooden sticks.