if there can be an Atomic Pull, there can be Korneel's cleaning method
I had 1 printer (yes, another UM2 has been bought) and i have several hot-ends. after a while i always had something happen with the hot-end (i have about 4000 hours on my printer). the printer is running almost continuously and i switch filaments quite often. this means that every now and then the hot-end just "junks up". there is debris all over it, ruining new prints and just attracting new burned filament. i swap out the nozzle\hot-end and i move on.. but this also means i have a couple of spare hot-ends. i tried different methods of cleaning them and i looked for suggestions. in the end, i came up with a consistent working method that is easy to do, cheap, and accessible to everyone.
what do i start with?
the nozzles usually look like this:
as you can see, there is burned\melted filament everywhere, in the hozzle, in the screw (hole) in the metal coupler, everywhere. in the past i would burn it off, but this would leave burned particles on the nozzles and ruin the thread. i had to then clean it off with a scalpel and it wasn't much fun.
so what do you need?
(PS i did this in the kitched, underneath the cooker hood running full blast since it was cold outside. always use good ventilation when doing this!)
-a decent underlayment where you can have plastic drip on. i used thick cardboard
-(almost) pure alcohol
-an old cup
-a decent gas burner
-a powder extinguisher or a fire blanket to put out any fires you might cause. DO NOT USE WATER!
i used this:
poor the alcohol in the cup so there is enough to immerse the nozzles and other pieces. make sure you do this below the hood, alcohol easily dissipates and the smell isn't good for you. it's also very flammable.
take the pliers and hold the nozzle or other part you want cleaned on a clean portion of the piece (for the nozzles i use the heater hole) and hold it just tight enough. by clamping to hard you can deform the piece.
put the gas burner on a concentrated flame and easily\slowly move over the piece so that the plastic starts burning\glowing. if the piece you are trying to clean starts to glow red you are burning to hot and start deforming it! copper will not easily deform at the heat you need to burn out the plastic so you should be good. there will however always be people that try to emulate the heat of the sun.. so hence the warning
if the plastic starts burning just let it burn.. make sure you do this below the cooker hood or somewhere else well ventilated. these fumes are toxic.
after you have burned off the plastic make sure it is no longer burning or glowing, then drop it in the cup of alcohol. you'll see it sizzle. move it around with the plyers then take it out and tap it against your solid underground. you'll see a lot of black junk coming off of it.
wait till it dries up then repeat the process untill it is clean. note: nozzles that you have burned more often will leave a bit of black residue.
make sure you can look through the nozzle! you should be able to see a very small hole.
once you are satisfied, you can simply polish the nozzle up..
before using the nozzle again make sure you do an atomic people (Taulman Nylon is the best material for this!) to remove the final pieces of burned filament. your nozzle will be as new again
you can use this not only for the nozzle but for all metal pieces that have plastic residue.
this is the junk you just took off;