Threaded insert that connects heating element and nozzle to extruder body broke off.
I have tried soldering it back in but the hole was already too big.
I tried super gluing it back in but as soon as the bolt gets any tension on it, the insert breaks off again.
I tried using JB weld’s Heat resistant putty, it worked for a few prints but the severe layer shifts problem came back and after taking apart the extruder again, I found the putty cracked and broke off as I was disassembling the heat sink.
OK, I think the best solution in this case, apart from replacing the whole thing, or going to a unicorn hotend which doesn’t use those screws, would be to use some ABS glue.
As far as I know the injection molded parts are made of abs, which luckily is soluble in acetone. The ABS will be dissolved in the acetone, then once the acetone dissolves it leaves only the abs behind which bonds to any other ABS present. This allows for some cool things such as ABS smoothing, or in our case, gluing 2 abs parts together.
Try taking some ABS glue and spreading it on the outside of the threaded insert, try and keep this amount as minimal as you can to avoid it leaking into the threads, but you will also want to make sure there is enough to properly bond the 2 pieces together. Because the threaded insert has crossing threads, once the ABS glue is added to it and starts to melt the ABS on the injection molded part it should be able to flow back into the threads and fill it up again. Once it is all dried out the ABS should have sort of been able to to flow back into where it needs to be and hold that piece in properly.
As a secondary measure if you have a soldering iron you can melt a bit of the surrounding abs and move it overtop of the threaded insert, once again please make sure that you are careful to leave the threads alone. If you melt a little bit of the abs over the top it may help to hold it in place better. But I wouldn’t rely on this method, try the ABS glue first and see how that works, if it seems strong enough then don’t even bother with the soldering iron.
You can technically replace the whole body, although this might end up being a bit of a job to complete. It would involve having to completely disassemble the motion system to get the toolhead off and then re-assemble everything again. Not out of the realm of possibility, but not the easiest thing in the world.
I have seen the insert sets that have 2 or 3 different ODs for a given thread size. It would definitely be a pain to have to get the toolhead out of the printer. Bondtec sells an “updated” toolhead and extruder. They have a good set of instructions for removing the toolhead.
