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Black Strings

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Hi, in all my prints so far I have had them speckled with some black stringy bits.


I have a feeling that it is filament that has leaked out above the hot end and dropped down, in which case how would I fix this please?

There are quite a few pictures here just in case you can see anything that is really obviously the problem.


(Just reading through here I have learnt 0.2mm layer height with mm/s is probably too fast but this is what I was printing at.


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Unless you want to use some ugly chemicals I don't any other way than to mount it properly while it is hot and then clean it on the outside as good as possible without twisting the heater block (as this is most probably the reason why it is leaking). In rare cases the end of the nozzle thread or the brass tube above could have a groove resulting in a leak.

Personally I would replace the parts if they are not to be cleaned with reasonable means.

Edited by Guest
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Ive tried the nozzle in nail varnish remover for about 30 mins, I cleaned it a little. I am now going to do what you suggest, thanks.

Replacing the parts is out of the question since I just got the printer for christmas.

What rotation is the Hot End meant to be in please, inside the wooden chassis.

Edited by Guest

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There's an important step. You need to (after cleaning the mess and doing some atomic pulls) you need to tight the nozzle while it's hot.

If you don't do that, it always leak.

Also, don't over tight it, the nozzle screw could break.

So first. Hot at 90 and clean the outside. Then do atomics to clean the inside. Then tight the nozzle while hot at 180C at least (and again carefully not overdoit).

Why after this many many years of Ultimakers, this step isn't explained on any assembly manual?

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