Drying nylon, in the microwave! DUH!

So i had bought some nylon a while back, the problem is its trimmer line, so its got a ton of moisture in it. so i didnt want to dry it in the oven because that would just take too long. initially i had good results using a hot air gun, then recently i thought of a microwave, a device that basically heats up water molecules, which is exactly what we want to do. so i put in a small coil for 2:00 minutes, it basically puffed up after 55 seconds, kind of a steam explosion i guess. I noticed it was steaming after wards and it was also much stiffer in the non puffed parts. basically my idea is to use a lower power setting now to slowly heat up the nylon so it will dry out without puffing. Im going to run this through my printer right now and see how well it works.

also you can buy a microwave for super cheap and just dedicate it for this if you wanted.

The same will probably happen even at low power because reducing power just makes it cycle between full power and fully off. The nylon will puff up each time the magnetron turns on for a few seconds.
What you can do instead is put in some soaked rags in a glass container in the microwave. The water in the rags will absorb most of the power leaving a smaller proportion of it to heat the water in the nylon so it heats more slowly and gently. I think it's even better if you put salt in the water used to soak the rags as it increases the conductivity so it should absorb more power.
The more wet rags you put the less quickly the nylon is heated. It will need some trial and error to get it right. Keep an eye on things and be ready to turn off if the rags start boiling then replace with newly soaked rags.

Do not use clear water in a container instead of the wet rags - it can be dangerous.

lister6520 Wrote:
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> ... I think it's even better if you put salt in the
> water used to soak the rags as it increases the
> conductivity so it should absorb more power.

Sorry, but that's nonsense, because conductivity has nothing to do with the absorption of microwaves here.

Water molecules (in liquid water) absorb the electromagnetic waves of a specific wavelength best (and other molecules do this at different wavelengths). The energy of the electromagnetic waves is almost directly converted to faster motion of the (or in the) molecules, in other words: their temperature rises (temperature is equivalent to molecular motion).
Because of this fact, ice needs a lot longer to melt in a microwave oven, than in a conventional one. Ice has a different absorption frequency than water.

Salt will not raise, but can lower the absorption, because there will be statistically less "ideal" molecules (molecules that absorb the microwaves best) in the NaCl-solution, than in pure water.

I think microwave ovens are not the best idea to dry nylon. But the sun can do it, instead of using electric energy. Think about a transparent case with some holes, placed in bright sunlight. After a few hours the nylon should be ready and you can store in a gas-close box with some Silica Gel in it. A box with a little hole for the filament could be used for printing. Silical Gel in the box consumes the humidity that enters the box through the hole.

$0.02

Hey, just read this

I dont think a microwave is a very good idea after looking at your results




I dried my Taulman 618 in the oven at 80c for 4 hours and the stuff discoloured alot, went brown, Prints very nicely tho, the stuff is sooooo dry its stiff, you can compare non dried and moisture ridden nylon, the dried stuff is very stiff, where the wet stuff is rubbery.
I hate the fact that its brownish color now, its only good for printing skeletons for a life like look, but i personally hate the brown colour, just looks burnt



iv had best results with a hairdryer attached to a cardboard box, but its just such a waste of electricity....


On the weekend i got a large black box, im going to drill some hole in it and try to use it to dry all of my filament.



Surely these is a fast way of drying this stuff..

Vacuum bake at modest temperature

Yeah it did work on a small piece actually, but not as well as an oven or a food dehydrator. it was worth a try though.

im glad you tried it!

maybe different settings on the microwave is going to get other results?

at harbor freight they have a food dehydrator for 20 something bucks, its literally perfect for this, its a cylinder large enough for a 1kg filament spool.

well im going to buy x2 of the dehydrators, one for my fruit and one for my plastics..

How long will it take to dry out do you think?

the proto paradigm people said they did their polycarbonate for 10 hours, but you could just cut off little bits during the first run every 30 minutes or so and see if it still bubbles.

I do mine at 200 degrees F while I sleep (about 6 hours). Stays white and flexible when dry.

NjEmt527 Wrote:
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> I do mine at 200 degrees F while I sleep (about 6
> hours). Stays white and flexible when dry.


yeah mine normally does, i think my oven is a bit crap tho, sometimes it will cook well, sometimes it wont, i know from previous roasting experiences
id say mine over cooked this time


now iv got a large plastic container, lay kitty litter on the bottom, and then a few bits of paper, and then put my filament over the top to try and keep is dry as possible

Edited 1 time(s). Last edit at 08/26/2013 02:21AM by nechaus.