New hardened steel and PETG CF = brass clog?

I recently purchased a P1S and ended up getting some PETG CF with the purchase because it was suggested. I realized the first time I tried to print with that that I needed hardened extruder and nozzle, so I ordered them. They arrived Thursday and I excitedly installed them and started a dragon print. It was going fine, but then about 40 layers in, it turned to garbage.

I was able to identify that it was a clogged nozzle and did a cold pull.

Its hard to tell in the picture, but under a magnifying glass, it looks like tons of flakes of copper! I did a second cold pull and got some additional copper right on the tip.

My question, where did this come from??? The only explanation I can come up with is that this was a coating on the hardened steel that all came loose after a few hours of printing??? Will it happen again? This printer is a week old and the hardened steel nozzle is a day old…and that is a TON of copper flake in that cold pull…please advise. Also…after the cold pulls I was able to complete that print.

It’s a ■■■■ when that happens.
I never printed their PETG-CF, but all other CF filaments without any issue.
I mostly only use the 0.4mm and 0.6mm hardened steel nozzles, and of course, I had clogs, especially with demanding filaments. However, mine seems to be hardened steel, as I never notice any coating being released. I already spent about one hour and a half trying every technique until I unclogged the 0.6mm HS nozzle. Yet without any visible wear in the metal.
What size is your nozzle? Did you dry the filament?

Not sure how much copper/brass is in the BBL extruder system. I haven’t torn it down it to be sure, but the I wouldn’t expect to see copper or brass in the nozzle. Not sure it would be cost effective to use multiple metals in such a cheap nozzle. It may have a bi-metal heat brake/throat, but I doubt it in the nozzle.

My first question would be what size is your hardened steel nozzle? And what filament profile is being used?

This was a brand new BBL .4 hardened steel nozzle. I did not dry this filament, but I did receive it from BBL a week ago and opened it only to get the message stating I needed hardened steel, sealed it back up and waited for the HS to arrive. I have printed this job successfully after clearing the clog and then another PLA job after that, and its still printing today without issues. I did examine the extruder and it was flawless, looks perfectly brand new, no flakes of anything or wear. I was using the Bambu PETG CF profile unaltered.

Technically, you don’t NEED hardened steel to print any filament, however, the stock stainless (and copper etc.) nozzles will wear quicker than a hardened steel one. I’d actually be more concerned with the stock P1P extruder gears wearing with CF.

These composites are moisture lovers; my PET-CF brand-new and sealed spool was wet. So, my first advice is to dry the filament; at least, you can discard this. Furthermore, it is suggested by BL for this PETG-CF.

I never noticed any nozzle coating, but I was not looking for it; if it exists, it needs to be in a material to improve surface resistance, and thus not expected to be affected with PETG-CF. A copper coating, indeed, would wear quickly with abrasive filaments.

I wanted to thank everyone and update where I got with Bambu Support. I want to point out that I was not troubleshooting a clog or bad print results, I was trying to find out where the metal flake came from that was in the cold pull…metal flake the caused the clog that I cleared with the cold pull. Support had me jump through a bunch of hoops, make videos, do additional cold pulls, tear down the print head, inspect the extruder gears, and send high resolution photos of everything…the source was never found. I didnt like how the hardened hot end was printing after pulling the clog, it made bulky lines with webbing with nasty overhangs and didnt look good so I put the stainless back on and making no other changes, resolved the printing issues. I feel the hot end is damaged…but Bambu was happy that I cleared the clog and closed my ticket. I think that hardened hotend runs too hot…it melted the silicon sleeve to the tip, there was a ton of burnt material inside the sleeve, not sure where it came from ether. I dont know where the metal flake came from, but I have no intention of using that hardened hotend again…so maybe I will buy another and disect this one…although I suspect dissecting hardened steel might not be worth it.