Printing with Line trimmer

[Cleveralias]

I posted this on a fail thread i started that probably won't get viewed much, so I'll repost it here where it's most relevant...

I got my hands on a nifty piece of equipment last week when I got my dryer up and running.

Been running some tests on filament moisture levels and here's what I've found...

I tested 4 different filament samples.

All filament was thoroughly dried by baking in an oven for 18 hours at 185F.

Control sample was left out in the open air for 72 hours
Sample 1 - airtight bucket with desiccant, no heat - 72 hours
Sample 2 - airtight bucket with desiccant, 40w incandescent bulb - 72 hours
Sample 3 - airtight bucket with desiccant, heated and compressed air flow through the bucket at 3psi, 40w incandescent bulb. PID controlled compressed air heater set to 130F - once up to temp, air would kick on every 30-40minutes or so and would take about 6-8 minutes to turn back off.

My shop's average relative humidity over the past week was 44.6%.

I measured the Rh% of each bucket, and then immediately printed a cal-cube with it.



Control Sample:
Rh% 44.6
When left out for, the trimmer line still prints, but it gives prints a very different finish. It's actually kind of cool, but it's noticeably different. I didn't noticed any major issues with layer adhesion, but I definitely got "pops" which left some uneven spots. There was also a fair amount of blobs on corners, and on small radii I noticed a lot of stringing. Nothing that ruined the usability of a print, but definitely not ideal.

Sample 1:
Rh% 31.4
It printed cleaner than the stuff left out in the open, but not a whole lot. There was less blobbing on retracts, but still stringing and "pops" while printing.

Sample 2:
Rh% 18.3
Printed very clean for the first 30-40 layers. Beautiful. No popping, no blobs - just perfect. Started to get messier as it went. I surmise that the outside of the spool dried thoroughly and the filament on the inside winding didn't/

Sample 3:
Rh% 4.8
Perfect print. When I print with this stuff, I never want to print with any other filament again. Great appearance, prints like butter, and amazing strength. Great bridging ability, and excellent surface finish.



Preliminary conclusions:
Nylon absorbs a LOT of water if you let it. There's likely a sweet spot between my Dryer Bucket of Justice and Awesomeness and the simple bulb-in-a-bucket. While I'm thrilled with my results, it's not really practical. I suspect that keeping Rh around 15% with some heat will produce the same results if the filament is allowed to dry for longer periods of time. Ideally, the filament would feed from the bucket to the extruder without being exposed to the air.

I'll post some pics of the prints when I get my SLR and booth set up. Tough to show the differences in surface texture with my phone.

Just wanted to post an update regarding the low-humidity molecular sieve dessicant. I ended up using just over a pound in my 30 gallon bin. It gets RH down to ~9% at room temperature, and with a 25w bulb in the box i'm down to 7%.

And I couldn't agree more about the trimmer line when it's nice and dry - beautiful stuff. I think I'll try dyeing the blue line black next...

[cope413]

Let me know if you have any success. I tried a little bit with some liquid Rit I had from a few years ago, let it sit overnight, and it didn't have much effect. I have a feeling it isn't acid-based so it wouldn't work with nylon, but didn't look into it much.

I know RichRap had great success, but all his stuff was natural, so not sure if it'll take another color once it's been dyed.

[lordbinky]

I believe you need to add vinegar to help it penetrate nylon,I'll try some and see how it does with red.

[cope413]

Vinegar likely only helps with acid based dyes (I'm guessing that acid in the dye is similar in pH and/or composition to acetic acid), but please let me know about your results. I'll get around to it, but currently have too much going on to mess with something new

[lordbinky]

Initial signs show it took. I'll post pictures and my method in a little while. Filament will need to be dried before i can print with it to see the result.

[Eaglezsoar]

Initial signs show it took. I'll post pictures and my method in a little while. Filament will need to be dried before i can print with it to see the result.

If you can, please give us your thoughts on how your process could do a whole spool of the stuff. If you have been using the line trimmer nylon you have an idea on how big
the spool is. By the way is your real name Harold? Mine is Carl in case you didn't know that.

[cope413]

Carl - did the spool holder work out for you?

[Eaglezsoar]

Carl - did the spool holder work out for you?

Yep, worked out fine, thanks!

[lordbinky]

Ok, so I took pictures after I dried it since I was busy doing other more 'responsible' things My apologies for not being more precise I just winged it to gauge the effectiveness.

I used:
- Glass bowl
- Rit Liquid dye : Scarlet ( maybe a quarter of the bottle?)
- 1 Cup White vinegar (the only thing I actually measured.... )
- 1 or 2 cups hot water (I COULD figure it out by filling up the bowl again, but it's already been cleaned )
- I put in some natural taulman 618 and some of the blue trimmer line
- Some string to tie the filament together. I didn't want part of the filament lifting above the liquid.

Just placing the filament into the bowl and letting it soak for a couple hours just tinted the taulman filament, and nothing noticeable to the blue nylon.

So I figured I was missing some heat. I looked at the oven and thought how long that would take, so I went for the microwave above it. I covered the glass bowl with a paper towel so I didn't make a mess, and hit 2 minutes on the microwave. I ended up microwaving it for 2 minutes every few minutes and then feeling the bowl to see how hot I was getting it. I think it was 6 or 8 minutes of microwave time total, I stopped when the bowl was hot enough that I would prefer not to touch it for long but not to where I burnt myself. Then I just let it sit for another hour or so and when I checked on it... the taulman was a nice red shade and the blue trimmer line turned a dark purple! Victory! ....until I see how it prints... but until then Victory!

Here's crappy cell phone pictures :

[lordbinky]

Initial signs show it took. I'll post pictures and my method in a little while. Filament will need to be dried before i can print with it to see the result.

If you can, please give us your thoughts on how your process could do a whole spool of the stuff. If you have been using the line trimmer nylon you have an idea on how big
the spool is. By the way is your real name Harold? Mine is Carl in case you didn't know that.

I'm just a Josh, nothing as unique as a Harold.

[Eaglezsoar]

Initial signs show it took. I'll post pictures and my method in a little while. Filament will need to be dried before i can print with it to see the result.

If you can, please give us your thoughts on how your process could do a whole spool of the stuff. If you have been using the line trimmer nylon you have an idea on how big
the spool is. By the way is your real name Harold? Mine is Carl in case you didn't know that.

I'm just a Josh, nothing as unique as a Harold.

Well by Gosh, Josh it is. Harold is relegated to acid bath.

[smiley]

instead of baking the stuff, has anybody tried parking it somewhere with a vacuum pump running? Like in a bell jar or whatever? For long-term storage that would seem most efficient, but I guess you'd need to engineer a way to get the filament out of the container without losing too much vacuum. Like, route it out through multiple O-rings.

There's a product idea in there somewhere.

Preliminary conclusions:
Nylon absorbs a LOT of water if you let it. There's likely a sweet spot between my Dryer Bucket of Justice and Awesomeness and the simple bulb-in-a-bucket. While I'm thrilled with my results, it's not really practical. I suspect that keeping Rh around 15% with some heat will produce the same results if the filament is allowed to dry for longer periods of time. Ideally, the filament would feed from the bucket to the extruder without being exposed to the air.

I'll post some pics of the prints when I get my SLR and booth set up. Tough to show the differences in surface texture with my phone.

[Cleveralias]

I had a partial success with my black dye job. I followed RichRap's post and pre-heated the nylon in boiling water and didn't use vinegar. I let it sit for about 45 minutes. When it first came out it looked like it had taken perfectly, but that was just the surface and after rinsing it came out much less dark. While it's not black, it's still a very nice shade of blue, so I'll call it a partial success.

I'll give it another shot soon and maybe try two packs of dye, and I'll give a run with vinegar too for comparison. I also bought some yellow dye and will give that a try soon.

[0110-m-p]

Better idea is to put the dye in the pot of boiling water with the nylon. It should only take about 15 minutes. I have a lot of experience dying keycaps for keyboards (mostly PBT) and that is the only way to get the dye to take correctly.

Personally I use a pot that I never intend on using again.

I'll take pictures of an IBM Model M that I did in yellow and black if you like.

[cope413]

You have to remember that this line has already been dyed. The blue dye in the line will mix with whatever you're using. Mixing it with yellow dye will give you some form of green. Black should work best because with enough of it, you can get to a true black.

[Cleveralias]

I essentially did that, just pre-heating the line in a separate pot. So I put ~100*C trimmer line in a pot of ~100*C dye, which was then taken off heat. Are you saying you keep the pot boiling for the 15 minutes that you're waiting for the dye to set?

And cope413: yes, with the yellow dye the desired outcome would be green filament of some shade. It prints very nicely but there's only so much bright blue I can look at!

[cope413]

Yeah, try keeping it at a boil. You won't hurt the nylon. Definitely add vinegar though, and I would suggest adding more dye than you would expect.

[Eaglezsoar]

Do you unspool the whole 3 pounds, dye it and then re-spool it after it drys?

[cope413]

I died my first amount last night. Unspooled about 1lb of it, dyed it and left it soaking overnight. It's drying but it looks pretty black.

If the results from this amount are good, then I will attempt to dye a whole spool.

I did rig up a spooler using a 12v 100w motor and this part I made that presses onto the axle. Empty spool slides onto the plate, and I control the motor speed while guiding the filament in nice even layers

[Cleveralias]

Yellow produced a nice green, and red gave a good lucking purple. As for the tie dye, well, this makes me happy. Used a cup of vinegar this time with about one cup of water and did leave it to simmer for about 30 minutes.

[Flateric]

I might also suggest buying a liter of printer refill ink in bulk. Slightly more expensive but let me tell you the color will be exactly as expected and deep and rich.

I use the same ink from printers when I am anodizing something.

[0110-m-p]

Is anyone printing Nylon with the stock hotend or is everyone using an all metal hotend like the E3D?

[cope413]

NO!!

Do not try to print with the stock end. PEEK begins to breakdown around 240C and begins to melt around 250C - and it emits toxic fumes when it does. PTFE begins to melt at 260. Also emits toxic fumes...

Nylon needs to print at 260-265 to get good layer adhesion.

Gotta have an all-metal end to print with nylon.

[0110-m-p]

That is what I thought and is why I was planning on upgrading to an E3D hotend after getting my printer calibrated and running well with PLA.

The reason I asked is because I was reading the Taulman website and it says that the Taulman 618 has a print temperature between 235C and 260C with the best bonding being around 245C. So, I wasn't sure if setting it at the 235C low limit and using the stock hotend was a possibility in the interim before picking up a E3D.

Also, I thought I read that PEEK had a peak working temperature in the mid 240C range?

[cope413]

Not all PEEK is the same. The highest I've ever seen it rated for continuous was 249, and that's PEEK 1000. Not sure what SeeMe uses, but it's always best to give yourself a comfortable margin from your operating limits.

Take Taulman's info with a grain of salt. He has nice filament, but there's not much science offered - mostly marketing.

240 with 618 will print, but it delams about as easily as PLA.


PEEK 1000 data sheet
http://qepp.matweb.com/search/DataSheet ... 12A&ckck=1