Suggestions for changing Bronzefill and Brassfill filament?

Hi,

I normally use the 80C cold-pull technique to change PLA filament.

While this works fine for ordinary coloured filament I have found that for Bronzefill it is not so good. The brittle nature of this material means that even with the gentlest of pulls it is prone to breaking.

Fortunately on my latest change it broke at, or just below, the hobbed bolt and I was able to purge it out by simply pushing down the replacement filament while extruding at the Bronzefill working temperature.

I am about to try some Brassfill which comes with a warning that it needs to be handled very carefully. I take this to mean that it is extremely brittle and I suspect very likely to break under cold-pull conditions.

Is it a viable practice to chase replacement filament into the extruder after trimming the old material? I do not want to be in the situation where I have to strip down my extruder following a botched filament change.

Suggestions?

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

I did that recently while the machine was printing as I underestimated how much filament was needed! I wouldn't recommend it though because there is a chance the second filament might slip off the old one and miss the hole and jam. Then you would need to clean the hobbed bolt.

I would simply do a hot pull at full extrusion temperature. That should get all the solid part of the filament out and break at the molten part. Then feed the new one and flush a few meters to get rid of the molten part of the old one.

The motivation for doing a cold pull is to get all the filament out to avoid the need to flush, but if the filament breaks instead of coming out in one piece hot pull is the best you can do.

Edited 1 time(s). Last edit at 04/21/2015 06:17AM by nophead.

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[www.hydraraptor.blogspot.com]

Hi,

Thanks for that. It looks like I will be removing the Brassfill sooner than I expected. It was a bit of a disaster.

This material exhibits elastic properties and behaves unlike any PLA I have seen. ColorFabb state that their PLA/PHA combination is tougher than PLA alone but this stuff is squashable and if you drop it, it bounces.

I was unable to remove it from a heated bed without cutting it away with a knife. It even printed onto an unheated bed and would not come off.

Definitely a beta product. In fact I am not sure it would qualify as being good enough for that label. Avoid if you possibly can!

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

I think in general rubbery/elastic plastics can be printed on cold glass because they don't contract with any significant force and that is why they don't release when cold as well. They are effectively above their glass transition at room temperature.

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[www.hydraraptor.blogspot.com]