Remember it could always be worse...

I will start off by saying I am not looking for pity nor is this a negative post about Lulzbot. This post is here for all of the new reprapers out there who just started the hobby and have printer issues. I remember the feeling when I started a few years back seeing these awesome looking printed Yoda heads and then looking at my spider web of a calibration block asking "Am I the only person having issues?" After a years of building printers and helping others I can tell you, there will always be issues no matter if you are new to the reprap, or a veteran. Case in point my recent hot end failure. Here is the short version.

I just got two new rolls of filament, was about to make a new phone case when things started going down hill.
First it started with switching out nozzle sizes. In doing so the center threaded barrel started to twist in the heater block. This is the first time this happened in the year I have used this hotend.
I started to break down the hotend when one of the leads from the heat resistor broke off. Now I take my hotend on/off quite a bit so it was not too surprising that this took place.
I was taking the bottom off when I found that the wood plate was deformed, chard, and broken in half.
I tried to remove the heater block from the threaded barrel, but got stuck .25" from the end. The heater block was grinding away at the barrel threads seizing it all up.
In order to remove the remaining wood plate I had to un-thread the barrel to the heater block and PEEK isolator. Not as easy as lulzbot says it is, I ended up grinding away at the PEEK isolator but was able to remove it.
I got to a point where I decided to give up on the threaded barrel and just grip-it and go to salvage the heater block. No such luck even with heat I can not break the two free.
Defeated I resorted to my wallet to fix the issue to find that lulzbot no longer sells replacement parts for my hotend (Version 1.2).

Sigh....

So remember everyone you are not alone with your printer issues. Even individuals who have been playing around with printers for years have problems. It may seem like you have hit a wall and nothing will ever fix it, but don't quit. You will get past your issue, and learn from it. This is all part of the hobby. Also remember no matter how bad you think your printer issue is.... It could always be worse.

Printer parts are a lot like so many other things in life... The more things heat up - the harder they are to separate. Looking at the issue you had, I'm thinking that it may be a good idea to coat threaded items that are prone to seizing with a small bit of anti seize compound (auto parts store) on the threads of hot ends, hot bed adjustment screws etc.

Well if you *do* go with the anti-sieze approach, be carefull you might get into:

Decided to "trust" the printer and run out to the store. What could go wrong…

Filament snarled on the feed spool and the extruder just kept pulling. This and that wound up torqued as a result. After a few hours quality time spent re-doing this and that everything *seemed* ok. Printer won’t print. Next layer to the problem – all the tear down and rebuild had convinced the center of the hot end to unscrew from the heat sink (it’s a Magma - not their problem). The center was about to fall out entirely. Crank it back down tight and move on.

Stuff happens. Never Seez high temp is a pretty good choice if you do decide to try something. If your hot end gets to a temp that it can't handle there won't be much left anyway...

Well Bob, I'm going to have 7 hot ends in a space the size of an egg. I am rather concerned with heat (I will be water cooling) and having a 25 year old Ford, I know rather well the frustration of a fastener or bolt that won't come out. Especially since in that year, they had fasteners that were half and half sae/metric. Aircraft often use the safety wire method of keeping bolts from escaping, I may try a variant of that approach.

I've spent enough time doing pipe fitting on stainless steel pipe to understand the issue of a stuck bolt. I'm by no means saying don't do it. The gotcha is that these assemblies seem to lock up only by friction. No lock washers or safety wires ....

Quote
ikilledkenny
I got to a point where I decided to give up on the threaded barrel and just grip-it and go to salvage the heater block. No such luck even with heat I can not break the two free.
Defeated I resorted to my wallet to fix the issue to find that lulzbot no longer sells replacement parts for my hotend (Version 1.2).

What about this? [www.lulzbot.com]

Granted if it's the threaded barrel and the PEEK isolator you're looking for you're out of luck, but the v1.1-1.3 wooden plates and heater block are still available as replacement parts.

FYI Gadget3D sells a Buda-style hotend clone based on v1.1 and it is significantly cheaper than the Lulzbot one. You might use it for spare parts to rebuild the original (assuming G3D didn't change the specs)...

Quote
NormandC

What about this? [www.lulzbot.com]

Granted if it's the threaded barrel and the PEEK isolator you're looking for you're out of luck, but the v1.1-1.3 wooden plates and heater block are still available as replacement parts.

FYI Gadget3D sells a Buda-style hotend clone based on v1.1 and it is significantly cheaper than the Lulzbot one. You might use it for spare parts to rebuild the original (assuming G3D didn't change the specs)...

The PEEK is still usable just ground up on the outside a bit. I was playing with the idea of getting the wood plate and heater block, but both of those items I am confident I can make myself, it is the threaded part I am a little iffy about. Thanks for the info on the G3D I may have to try that out.

Uncle Bob, My approach is to 1. apply anti seize 2. snug the bolt down to a reasonable tight* 3.install a safety wire or pin to keep the fasteners from loosening due to thermal or vibration causes. *I have learned a great deal about "apparent" torquing over the years - that is the point at which a really small fastener (# sizes) feels like it is properly tight to do the job, and to be retrievable later, due to the fact that I spend a great deal of time using and maintaining a variety of my own machines. After a while, you get a feel for it. Not to say that I don't use torque wrenches - I have and use a few of them, but just as with manual machining, how fast, how tight, what size... these things become intuitive thru feel over time.