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devilhunter
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WHY do these printers still not ship with hotend socks?

Sat Feb 17, 2018 10:18 pm

As the popularity and the shipments of the Prusa i3 MK2 grew, it started popping up everywhere.
Reddit, Facebook feeds, Thingiverse. Just about everywhere you can recognize the MK2 right away from a photo that does not even show more than a few parts of the printer.

The "ORIGINAL PRUSA" on the heatbed, the "HOT!" on the nfan nozzle, the bright safety ABS orange parts.

And just about every 2 or 3 days i see these catastrophic fails on a MK2, aka Hotend blobs on Reddit, and on Facebook. Sometimes even on Twitter or Thingiverse Forums. Photo included is from Prusas own knowledge base.

These catastrophic failures can have only two reasons:
- Print lifted from the heated bed and got stuck on the big 200+ degrees heaterblock, new extruded filament will collect there as well as one massive molten blob.
- Nozzle or heatbreak not correctly tightened into the heaterblock when hot. Filament will leak out over time then, and will slowly drip almost as a liquid onto the bed, while still accumulating on the heaterblock.

More than 90% of these catastrophic failures can be attributed to the first error, the print lifting from the bed and sticking to the heaterblock.

People try to fix it almost always do it wrong, ripping off thermistor cables or damaging other components.

And almost all of these 90% could be avoided if Prusa would throw in just one or two E3D Silicone Socks. Prusa, you supply the genuine E3D hotend already, why not throw in a 1 dollar silicone sock?

I've been using the sock since my first 'almost' catastrophic failure a year ago, never had a problem with them since.


The silicone sock has these benefits:
- clean heaterblocks & no catastrophic blobs on the heaterblock forever
- the temperature of the hotend is MUCH more stable, even without PID tuning, as you can see in octoprint's temp graph
- the Printer will consume less energy because there is no filament fan that keeps blowing some of the cold air onto the heaterblock. the Heater cartridge has to work extra hard to keep the heaterblock hot; with the silicone sock no cold air gets to it, and the silicone even has a heat conserving ability for the heaterblock. you can actually measure this with a watt meter, the printer will consume about 4 - 5 watts less with the silicone sock on the heaterblock.
- provided you cool the 3D prints adequately and avoid upwards curling prints, the silicone sock will last months. Sharp curling prints will rip off small pieces of the silicone sock, or in some cases will rip off the sock from the hearblock entirely. (the sock survives this unharmed)


Mr. Prusa, why is this silicone sock still not included even with your newest and most 'smartest' of your Printers?
Raise the Price of the Printer for one dollar for all we care, this saves a lot of people big headaches with the issues mentioned above.
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curtis.c2
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Re: WHY do these printers still not ship with hotend socks?

Sat Feb 17, 2018 10:37 pm

In principle I agree, but I've had failures even with a sock. heater block cable gets tweaked and sock starts to droop, etc. It doesn't absolve us of properly cleaning the nozzle, either. I have a whole bag of of genuine socks and the fit is hit or miss.

No issues with temp stability here, but I can see the argument for keeping heat away from small details and shorter layers.

corey.d3
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Re: WHY do these printers still not ship with hotend socks?

Sat Feb 17, 2018 11:01 pm

Here's why I think horned socks could be a bad idea. Over time they will become loose and no longer sit on the tip of the nozzle properly. With the sock no longer securely fit against the block filament can extruded into the sock and cause a blob.

This actually happened to me so I speak from experience. The sock became loose, dragged onto a print, and filament started to extruded into the sock causing a blob. Thankfully I caught it in time and didn't become another blob victim.

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Iluvatar
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Re: WHY do these printers still not ship with hotend socks?

Sat Feb 17, 2018 11:03 pm

I ask them with the chat before the shipping if they can put one sock with my printer. I receive 4 of them

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joan.t
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Re: WHY do these printers still not ship with hotend socks?

Sat Feb 17, 2018 11:10 pm

I too, had a blob that was trapped inside the blue sock, and directed straight into the cabling on the heatblock!




it looked like the original print, detatched from the printbed, and skated around, whilst the extruder continued to pump filliment out of the extruder, the silicone sock, seemed to act as a thermal barrier, causing the filament to flow inside the sock in preference to outside the sock...


regards Joan
I try to make suggestions that I believe to be well founded and safe,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions,
what you do, is YOUR responsibility.

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moojuiceuk
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Re: WHY do these printers still not ship with hotend socks?

Sat Feb 17, 2018 11:14 pm

Josef himself has said this about including a sock:

We’ve had to many socks fall out on the farm ruining the prints and hotends to include it ...

original-prusa-i3-mk3-f30/is-a-silicone ... 6-s10.html

I love the socks Ive put on my K8400 and I have a sock ready and waiting for my MK3 when it arrives. In my opinion they work, but I don't have 300 printers working 24/7 :D

patrick.v8
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Re: WHY do these printers still not ship with hotend socks?

Sat Feb 17, 2018 11:55 pm

Indeed i read or heard Joseph say they had troubles in the print farm using the socks.

That being said, i also have 2 original socks ready and waiting for my mk3. the 3rd of the pack of 3 is currently installed on my clone printer (as the one that i got with the Titan Aero on that machine was becoming loose).

I think that although they have had issues with them on the print farm, i would have liked it to be included. But just with a warning that you should always make sure the sock is not too loose, and if so you know it can be a rist.

george.b2
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Re: WHY do these printers still not ship with hotend socks?

Sun Feb 18, 2018 2:31 am

I have about 10 socks on hand and have used them since I had a blob on my MK2 last year. I also had a near failure saved by the sock on at least one occasion and I mentioned it in the MK2 forum.

From what Joan and others have experienced with the sock catching and holding on to filament after slipping off, I wonder if the catastrophe would have still occurred without the sock anyway??? May be impossible to discern. I personally think the advantages outweigh the disadvantages. But, I agree with Josef not providing them and letting the individual user decide. The socks can be bought from multiple sources in multiple countries so the shipping costs are not really an issue and they are pretty cheap.

richard.p16
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Re: WHY do these printers still not ship with hotend socks?

Sun Feb 18, 2018 5:06 am

I have said the same thing many times. Why wasn't I born with socks on? I put them on every morning and think why God didn't include socks? He's Bloody Omnipotent for Christ Sake.

curtis.c2
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Re: WHY do these printers still not ship with hotend socks?

Sun Feb 18, 2018 6:00 am

joan.t wrote:
Sat Feb 17, 2018 11:10 pm
I too, had a blob that was trapped inside the blue sock, and directed straight into the cabling on the heatblock!
Same here. easier to brush clean or pick away stringers during a print without it too.

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