Sunlu Filament dryer box

sprzout

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With some of the problems I've been experiencing with PLA and Southern California desert temps over the past year (namely, motor mounts and control horns warping in the sun) I decided I was going to give PETG a try.

For those that don't know, PETG is more heat resistant than that of PLA - typical print temps for it are usually in the 230-245 C heat range, and because of this, it will hold up better in the 100+ Fahrenheit temps that I see at my flying field during the summer.

I bought a roll of Overture PETG from Amazon, along with a textured PEI print bed. If you have a smooth PEI print bed, you can use that, but you'll want to run blue painter's tape over the smooth surface; otherwise, you run the risk of having the PETG bond to your PEI surface and actually remove chunks of the PEI, ruining the print bed itself. I ran several prints of firewalls and control horns, trying to dial in the settings for my PETG, and noticed I was getting severe stringing, material not sticking to the print bed in spots, and a lot of problems pointing to the material itself. After a bit of investigation, I discovered that the issue that was causing the print to have blobs was that the PETG was actually boiling in the hotend. Turns out this was caused by moisture in the PETG - PETG is VERY hygroscopic, meaning it absorbs moisture from the air like a sponge - and so that moisture was boiling out through the nozzle and causing the material to pop and spit.

Several people have reported using desiccant packs to dry out their materials so it wouldn't boil; I thought I'd give that a try. It eliminated some of the bubbling and boiling, but it didn't get rid of it completely.

Friday, I got notification from camelcamelcamel (a tool I use for finding Amazon deals and price changes on items I have on my wish list) that Amazon had dropped their Sunlu Filament dryer box down from $60 to $40. I pulled the trigger and bought one, just to see if it would help. Boy howdy, does this thing work at getting the moisture out of the filament!!!

What it does is it has a heating element in the unit that warms the material from 20-65C, for anywhere from 1-24 hours (after which it will shut off and stop drying out the material). For my PETG, I ran the dryer for 3 hours at 50C, and then tried a test print of a Master Series control horn to see if it would print out smoothly, or to see if I had any popping like I'd had earlier this week. Zip. Zilch. Zero. Nothing. NADA on the popping front. Even better, the prints for PETG are now much more stable, and the material is printing smoothly, just like if I were to run a PLA print.

Doing my research on this, several blogs and forums have said people have tried doing a bake of their material in their ovens, with varying degrees of success; most of that success came from having an oven that kept the temperature constant, and was able to get it low, generally in the 50-65C range (for PETG) and keep it there for 4 hours. This MIGHT be a good option if you have several spools of the same material that you want to dry out, as you could potentially fit multiple spools in the oven at once and dry them out. However, there are disadvantages to this as well; if you're trying to dry material in the oven and your oven is not maintaining a consistent, even temperature, you could have the temp climb and fall, melting the filament and bonding it to itself, thus ruining your entire spool.

Other people reported that they were able to buy a food dehydrator and use that to dry out their filament; when I looked at that option, I would have had to take the filament off of the spool or cut up several of the trays to fit a spool inside for the drying. Plus, buying a food dehydrator would have cost me the same as the Sunlu filament dryer cost, brand new, from Amazon, so for me, it was a no brainer.

If you are finding that your prints have a lot of blobs, stringing, inconsistent extrusion where the layers are looking narrow or wider from layer to layer when it should be consistent, or if your PLA is brittle and snapping as you try to feed it through the hotend, I'd highly recommend trying to dry out your filament, and I can't recommend the dryer box enough. It's done wonders for me already with multiple prints, and I'm willing to go out on a limb and try it for all of my other filaments that I've been having some printing problems with to see if it helps reduce the stringing or inconsistencies. :) At any rate, well worth the $40 I spent!

Link for Sunlu Filament Dryer Box - Amazon
 

Balu

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Staff member
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Sunlu just had a sale with the same price. I wonder if they are getting rid of their stock for a newer model :)

Anyway I have ordered one myself, since I want to play with TPU. Still waiting on it though.
 
M

MCNC

Guest
So you are out flying with the temperature in the shade over 100F.....? Or is there no shade? Dedication
 

sprzout

Knower of useless information
Mentor
Sunlu just had a sale with the same price. I wonder if they are getting rid of their stock for a newer model :)

Anyway I have ordered one myself, since I want to play with TPU. Still waiting on it though.

Works great for the TPU as well; I used it while printing some wheels and treads for the Bushwacker, and the TPU laid down nicely. One word of advice if you’re printing TPU with a direct drive printer (like the Prusa i3 MK3s or one of its clones) - loosen the idler bolt as much as you can to let the TPU slide through. Otherwise you run the risk of the idler gear teeth getting jammed up with TPU and you’ll end up having to take apart the extruded to clean it all out, and that is a PAIN.

Also, do a cold pull with some nylon or PETG after you’re done printing TPU; that stuff is NOT fun to clean out!
 

sprzout

Knower of useless information
Mentor
So you are out flying with the temperature in the shade over 100F.....? Or is there no shade? Dedication

Oh, there’s shade, but it can get up to 100 in said shade. And even then, PLA will get mushy and warp in the shade. PETG holds up a lot better in that heat. 😁
 

Robert S

Well-known member
Printed a means to attach a PTFE tube coming right out of the dryer and ending so that the filiment feeds directly down to the direct feed printer head.

If interested, look it up in thingiverse. There are a few different versions.
 

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