I have had 4 hotends clog so bad I had tohit them with a torch for a moment then use a small allen to press the filament out. I am using nylon PA612 and PA6 on a .4mm nozzle, I have read here that others using .4 with nylon. So what’s the trick I need the quality of the .4 running layer height .12. Any advice you can give me.
Nylons have to be very dry before you print with them. Especially PA6 in that not only do you need to start dry but you also have to print while drying. Damp nylon will for sure easily and quickly clog a 0.4mm nozzle. Also, PA’s are for functional parts. I would go with a 0.6mm non-HF nozzle.
I am printing functional parts, firearms. I am a FFL holder and a manufacture so I need the strength. I also dry my filament and I do print from a heated box. Actually, my fiber comes out of the box and right into my dry box and stays there for the duration.
PA filaments have to always be immediately dried at 85°+ for 8-12 hrs before a print, even brand new from a factory sealed bag. You can maybe store PA6 in a dry box for 2-3 days maximum before you have to dry again. If you print it out in the open you have maybe have 2-3 hrs before it becomes unprintable unless you live in a dessert.
It seems that you are doing that already.
Also, do not use a high flow nozzle. I use Diamondback nozzles with PA.