Nylon Moisture

So I recently bought some alloy 910 nylon filament from taulman 3d and I am having great difficulty with the moisture issues.

I have a (mostly) airtight container with about 20 dessicant packets inside as well as a tube to my printer.

I dried the nylon in the oven for about 8 hrs at 180 F, and as soon as I started printing with it in the container there were bubbles in the print and cracking noises when I started printing.

I thought that I accounted for the moisture enough, does anyone have any suggestions to get rid of the bubbles?

The oven temperature is too low. I used 3 hours at 150 degrees C (302F) and it was very nice, smooth and transparent to print while undried it was like foam, milky and not transparent. Don't throw in the spool, it will melt and it may be difficult to extract the nylon. The nylon itself will stay very solid. Just cut off a piece you'll need (repetier host will display the estimated length) and bake it just before printing.

I've also found in humid conditions the nylon soaks up moist pretty quickly, within 24 hours some bubbles could be seen already. I kept in in a sealed container with silica packs but still got some bubbles in them. It's best to dry the nylon just before printing when it's very humid. My guess is in air conditioned rooms or dry climates the nylon is much easier to handle.

Nylon will become brittle when the moist is removed, so make sure your printed object is subjected to water (I usually soak in for an hour in water). It will be a bit softer and bendable, the layers will stick together better.

Edited 1 time(s). Last edit at 09/02/2015 01:58PM by imqqmi.

I dry mine in the oven @70°C for 3-4 hours, then keep it in a sealed container with a huge amount of silica gel at the bottom.

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[www.bonkers.de]
[merlin-hotend.de]
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What´s the huge benefit of nylon against PETG?
-Olaf

I guess it can also depend on the filament thickness. 1.75mm vs 3mm. Mine is 3mm and takes more heat/longer drying.
I haven't used PETG yet so I can't comment on that. Could it be that PETG gets soft at lower temperatures than nylon?

Quote
imqqmi
I guess it can also depend on the filament thickness. 1.75mm vs 3mm. Mine is 3mm and takes more heat/longer drying.
I haven't used PETG yet so I can't comment on that. Could it be that PETG gets soft at lower temperatures than nylon?

Mine is 1.75 that should make quite a difference in how long it takes to dry.
I only tried PETG very shortly, but i have ordered a roll and will try.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

I had this problem with the 910; filaments were 'frothy' unless I pushed it through very fast. I was keeping my filament fairly not greatly dry. Nylon tends to really suck up water. Note that Nylon can change it's dimension by as much as 7% although I'm not sure how much saturation that is. But 7% is .2mm of a 3mm filament so that could easily get too big for the heat-break.
Taulman told me though that 910 has 40% water absorption of regular nylon.
However...
I sent some extreme close-up photos to Taulman and they said 'Too hot, the plastic is boiling'. Didn't know this could happen!
I dropped the temp down in small steps until I got a clear flow. It worked! (viscosity did not change noticeably).

Taulman does a lot of R&D on their materials and therefore have a lot more interest in user feedback; our correspondence was very verbose and their replies quick. Try that with a Chinese manufacturer!

Can you link those photos of the boiling plastic? I'm struggling with nylon moisture too and my nylon does something that fits the description, which I'm trying to eliminate.

I've attached a picture of the plastic, extruded by hand through the hotend.

This video shows the process:
Video of manual extruson of moist nylon

Edited 1 time(s). Last edit at 09/18/2015 05:52AM by krakadu.

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ShapeForger

What you have is water boiling off during the extrusion.
Since it can't really go anywhere inside the nozzle it pops out as bubbles in the filament.
On a printed part it will look fluffy and cause a very rough surface.

There are several ways of drying nylon, all with some drawbacks.
I will try to explain my own way, which is less power consuming but takes a bit longer.
I put the filament I tend to use, plus a bit extra inside a closed, clear container together with some silica gel (dessicant).
On the bottom is some black fabric and I just put the container out in the sun for the whole day.
I do the same with a bigger container to store bigger amounts of nylon if I have to.
Basically just to keep it dry.
This way and assuming the nylon is new from a hardware store or was real fialent but is too moist you get pretty good results.
However, nylon is a funny stuff.
If it is too dry it looks really shiny when printed by getting it to stick (on the bed and to itself) requires much more heat and lower speeds.
For parts that are subject to friction and that don't require a perfect finnish I actually prefer a bit of remaining moisture in the nylon to help with the sticking bit.
To accomplish this I simply use totally dry nylon and print it the next day

Another way to check if your filament is really dry is the ice trick.
Glue a piece of metal to the lid of a sealed container (inside).
Put the closed container in the freezer for an hour or two.
In the meantime heat the filament to about 100°C .
Quickly open the container, put the filament in and close it again.
Check after about 15 minutes the metal inside - if it still dry the filament is too, if there is moisture or even water condensing on the metal the filament is still moist.
It works even better in a vacuu as the water boils much sooner and so the moisture would condense on the metal faster too but not everyone has a vacuum pump at home...