Time to dehydrate filament?  

RE: Time to dehydrate filament?

I have never ruined a roll by heating too long, but I have by heating to hot.  Follow the temperature tables.  

I have had rolls get brittle because of overheating and over hydration.  It is worth a try.  

RE: Time to dehydrate filament?

I don't know if the gadget we have is similar to yours, but we have the Ninja Cooker, which has a dehydrate mode which goes down as low as 105F (~41C) and I've used it to successfully dry filament as well as to 'rejuvenate' the dry packs I use in my dry boxes.

Toward the first of the year I bought a (non-Prusa) printer and it came with a few partial spools of various filament.  One of them was so brittle that it could not be unrolled without snapping.  I set the Ninja for 105F and 12 hours and let it go overnight.  (Ain't got nothing, ain't got nothing to lose.)  It made quite the improvement and the filament is now perfectly usable.

A couple caveats, however.  This is 3mm filament, which is normally not as supple as 1.75 and may take longer to dehydrate, plus this is what they call 'tough PLA' which may be a different formulation than the Prusa(ment) PLA is.

In any case, I would try drying for MUCH longer, as in several hours minimum.  As long as you do not approach the glass transition temperature of the filament you should be good for many hours at a temperature of low hundreds F or low 40s C.

RE: Time to dehydrate filament?

@cwbullet

This. Too hot is worse than too long. 

I use 3 hours as a minimum but have left filament in the dryer overnight with no detrimental effect. 

RE: Time to dehydrate filament?

I use the print dry systems they don't seem to sell the round one anymore but mine still works great after 4 years.

I also own one of these, (see below) that I keep at work, and I have just ordered another for home.

This is the newer version, I consider them reasonably Priced, since they're just ready to go and just work.

You can just dry the filament in it, store the filament in it, or you can run the filament out of it while your printing.

I'm of the opinion that any food dehydrator will work as long as its of sufficient power, I chose these because all I had to do was plug it in and go, I have enough things to construct didn't want to add one more.

Good Luck

Swiss_Cheese

RE: Time to dehydrate filament?

@swiss_cheese

I have the same. Works as advertised. 

RE: Time to dehydrate filament?

@annier

I missed this in my first post, your filament is completely recoverable, I have yet to have one that could not be recovered though properly drying it. just like everyone else has mentioned stay below the glass transition when drying and you can keep it drying all week long if you so choose. you may also find some added benefit in drying as you print if you have that capability.

Good Luck

Swiss_Cheese

RE: Time to dehydrate filament?

I have three dry boxes for filament storage, each of them a simple Home Depot storage tub with an el-cheapo humidity gauge (mounted to the side with a 3d printed bracket, of course) and four of the silica gel dry packs.  When the humidity starts to creep up, I'll 'recharge' the dry packs, formerly in the oven, now in the Ninja Cooker set to dehydrate.

For the spools that I do not use regularly, as in use up before they pick up too much moisture, I keep them in these boxes.

One newer addition to this, which I may or may not have posted previously, is making one of the boxes into a makeshift dehydrator as well, using some spare lamp parts.  I only used this to test so far, as we got the Ninja Cooker shortly after I added this.  The idea is to warm the air in the tub and force the H2O in the filament into the dry packs.

RE: Time to dehydrate filament?

I might do an article on the dry box options I have used.  This topic is a great on for discussion.  A light bulb is a good idea to heat the box.  

RE: Time to dehydrate filament?

Posted by: @cwbullet

I might do an article on the dry box options I have used.  This topic is a great on for discussion.  A light bulb is a good idea to heat the box.  

One thing I forgot to mention is that for dehydrating, the idea is to move the filament to the side of the box away from the bulb, where the temperature will be more consistent and will not approach the glass transition temperature of the filament in it.  An incandescent light bulb can easily approach 200F or 90-some C.  I have a variac that I used to adjust when I first tested it, but a cheap light dimmer control would work as well.

It's important for this application to use a regular energy-inefficient incandescent bulb, as the curly-cue or LED types will not put out enough heat to warm the air in the box to 100-115F (38-45C) or so.

RE: Time to dehydrate filament?

yep, don't want to hatch no chick's 😉 

RE: Time to dehydrate filament?

@jsw

Good points!  

@all I also have each of the Printdrys and two food dehydrators.  They simply work.  

RE: Time to dehydrate filament?

 My original spool of Prusa grey has become very brittle. Snaps with even a gentle bending. 

This is very coincidental and will be a real good test case.

A few minutes ago I discovered a partial spool which is the remainder left over when I respooled a huge honking 2kg spool of the silver-gray PLA from Filament PM (appears to be the exact same stuff as the Prusa silver-gray sample spools) onto two regular 1kg spools about a year ago.  I literally forgot about it and it's been sitting in a corner of the spare bedroom for about a year, open to air.

I tried unrolling a bit of it to see how bad it is and it cracked and snapped off, similar to the Ultimaker filament I referred to above.  I would even say it's worse.

I just put it in the Ninja Cooker, dehydrate mode set for 12 hours.  This time I set the temperature to 120F, which, according to Chuck's chart above, is slightly less than 50C and should be safe for PLA.  This is one notch above the 105F I cited above.

This will be a very good test case as to what's recoverable.  I'll report back tomorrow.

RE: Time to dehydrate filament?

@jsw

At the very least what the air fryer can do. the filament is recoverable as long as it wasn't cooked to hot at some point.

RE: Time to dehydrate filament?

This should have never been heated.  It's been sitting in a corner of a residential room for about a year.  No heat vents or windows near it.

RE: Time to dehydrate filament?

@swiss_cheese

Per our recent discovery with ninjaflex I ordered one of these these morning also.   Ninjaflex just shrink wraps the box and doesn't vacuum pack the spool itself so it takes on moisture just sitting in the warehouse.  Annoying.

RE: Time to dehydrate filament?

yep my first wet Ninjaflex but the dryer sorted it out, to be sure.

RE: Time to dehydrate filament?

Ok, here's the report as mentioned above, and it is not good.

This particular spool I believe is beyond hope.

I put this in the Ninja Cooker set to dehydrate at 120F for 12 hours and let it run overnight.

When I first inspected it I unrolled a couple of turns and it seemed like it had recovered its normal strength, as a coil would bend and retain the bent shape without breaking.

However, as I unrolled more, it snapped off.  Then snapped off again after a couple more turns.

Inspecting it closely revealed many hairline cracks in the filament (you can see them if you look closely in the image below) and I'm sure this was a result of either being exposed to room air for over a year and/or being hand-wound too tightly on the spool.

I have maybe 1/2 of a 1KG spool, wound from the same 2KG spool, which has been kept in the drybox and it's fine.

Note the vertical hairline cracks, pretty much in line with each other, in the coils below.

RE: Time to dehydrate filament?

@jsw Don't despair too soon.  I have seen variations of this effect when oven drying very wet filament where the outer layers dried but the inner coils took ages - presumably some of the water migrated inwards as there was no ventilation.

Cheerio,

RE: Time to dehydrate filament?

@jsw, well, sometimes we just have to let go of our loved ones...