Lessons learned - 400 hour tear down

[DeweyOxberger]

So I'm at 400 hours of printing on my V3 and I just did a fairly detailed tear down and inspection of the print head (I'm replacing it with e3d). I noticed a few things worth mentioning.

First: Early on I had a hockey puck and major stringing. I turns out that did some damage to the bowden tube (and I didn't notice). The HE end of the tube is hollowed out a bit for the last cm or so. If you find you have hockey puck inspect the end of the bowden tube. You may need to cut off the last cm.

Second: The HE280 connector was slowly rotting due to excess heat in the HE power contacts. Once I noticed the rot I did a test and found the connector was heating to 60c on the surface. You may want to tell the HE to heat up, wait 30 seconds and touch that connector, if you notice it's warm it's on the road to an early death. The contact resistance was up to 0.50 ohms. The bulk of the resistance was in the wire to pin barrel (I measured it 4-wire). The metal showed signs of thermal stress. IMO that connector isn't good enough for 2.2 amps so I broke out the lines and used a Dean's connector for those pins (because that's what I had in my junk box and it's good for several amps). That was probably causing all kinds of inconsistency in the temperature.

Third: With the 4-wire meter out I went ahead and checked the crimp barrels on the thermal cut-off switch. They weren't holding up well either. In fact I found they were easily intermittent. The slightest wiggle would increase the resistance to 0.3 ohms. There was signs of thermal issues there (discolored and oxidized).

Lastly, I bought the e3d v6 with the bowden tube and found the tube was 32" long and you need closer to 34" - Ugh. The tube was way stiffer walled and I like it much better (I suspect you want stiff walls to minimize storing "spring energy" in the walls).

Anybody know a good source of bowden tube that is stiff-walled?