Problem with hot end

[Magnifico81]

Hi everybody!

I've a problem... my extruder is stuck.

How can I free the hot end without damaging it?
Boiling water? Acetone? Blowtorch?


I've a Printrbot Play, The plastic is PLA.

Thanks in advance.

[RetireeJay]

I'm not sure exactly what you are getting at. But when you want to change nozzles on your hot end, the way to do it is to heat the hot end to a temperature where the plastic softens. Otherwise, the threads on the nozzle will probably be so well stuck to the outer part that the nozzle will break before it comes off.

[Mooselake]

If you mean clean out the nozzle then the blowtorch technique will work, heat it up and then quench (i.e. dump it) in some rubbing alcohol. I use the flame on one of our gas cooktop burners. I use a welding tip cleaner to clean out the orifice, although a piece of wire (a wire from a fine brass wire brush is often mentioned) will do. Don't get one of those carbide drill kits that are sold in many places. Besides the bits being extremely fragile (I've broken them by brushing against them removing a nearby bit from the case) you want to clean out the hole without enlarging it. If you can see through it after the torch trick you don't really need to ream it out.

If you mean remove the nozzle (looks like you already did that) then bring the hot end to operating temp and unscrew it. There's flats at the top of the heater core you can old while doing this, but I just unscrew the tip with a short wrench. This can unscrew the whole thing so holding it might be safer.

Now that yours is disassembled you can clean out the metal parts with a hand held drill bit (not a hand held bit in a drill motor, just the twisty bit), carefully reaming out the crud with successively larger bits until you get to a bit over a mm, think noticeably smaller than 1.75, you don't want to bugger up the inside.

Normally you don't need to take it all apart (too easy to break wires), just remove the nozzle and go from there. Often just extruding plastic without the nozzle on is enough, otherwise read up on cleaning techniques like cold pulls. I just use a non-melty pipe cleaner and pull it through several times - some are polyester and can melt, some are something else (I'd guess cotton) and don't. If you're near a mall with a (tobacco) smoke shop they can probably help you out, just be prepared for the usual what kind of guns do you print nonsense.

Kirk

[Magnifico81]

I'll try to do so. Thank you very much for the help. Cheers.