Spare rear panel?

Discussion in 'Getting Started' started by orcinus, Aug 8, 2019.

  1. orcinus

    orcinus Well-Known Member

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    Bleugh. My rear panel’s developed cracks.
    They haven’t spread all the way through, and are limited to the rear surface (the one facing the T-nuts), so i guess it’ll be okay for now (unless is spreads catastrophically all of a sudden), but i was wondering if spare panels will be available for order later?

    I swear i didn’t overtighten them. They were fine, and there were no cracks until i started manouvering the whole thing around and aligning and tightening the extrusions. Then, the next thing i know, there’s cracks on literally every outer T-nut (and, interestingly, none on the middle ones that attach to the Z stage).

    I guess they should’ve been even looser than finger tight, to accommodate for the stresses during alignment and maneuvering the frame around.
     
  2. orcinus

    orcinus Well-Known Member

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    Yup, it was stressed… When i untightened them just now, the whole panel unbuckled (audibly) a little.
    It might be a good idea to update the build manual and leave tightening the rear panel as the very last thing.
     
  3. Greg Holloway

    Greg Holloway Administrator
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    Thanks for pointing this out, I have updated the docs.

    We shall see what we can do about sending a replacement panel. Can you confirm which one it is that has cracked please.
     
  4. orcinus

    orcinus Well-Known Member

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    It’s the one referred to as the Electronics Panel by the docs.
     
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  5. orcinus

    orcinus Well-Known Member

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    Uh oh, bad news. All the panels developed cracks overnight. They were fine yesterday and this morning.
    I checked up on the Toolchanger half an hour ago, and literally every single panel has cracks.

    I didn’t even tighten most of the nuts full 90 degrees!

    Temperature stress (had A/C on most of the day @ 21C, then opened the windows in the evening at 30 C)? Aliens? I’ve got no idea what’s going on… Did i flip the nuts wrong? I don’t think it’s possible to install them the wrong way around, right?
     
  6. orcinus

    orcinus Well-Known Member

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    Just checked, and nope, definitely oriented right. Also, some of the cracks are now several cm long o_O
     
  7. orcinus

    orcinus Well-Known Member

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    A video of undoing one of the nuts, just to demonstrate how (not) tight they were:



    Here’s what one of the cracks looks like up close:

    [​IMG]

    The “wings” above the crack aren’t surface damage, they’re inside the acrylic.

    It looks like some of the threadlocker ended up wicked into some of the cracks.
    Could the threadlocker somehow precipitated this? I’ve used genuine Loctite 243, albeit a bit older bottle (in fact, i’ve just noticed it didn’t cure completely since yesterday).
     
  8. orcinus

    orcinus Well-Known Member

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    UPDATE!

    Yes, it’s Loctite 243!
    Don’t use it on the panels!

    Here’s a closeup of an edge that was exposed to a tiny drop of 243 that ended up on the bottom plate:

    [​IMG]

    Apparently, it’s common knowledge too (of which i was completely unaware of until now):

    https://www.google.com/search?ei=Qi...hUKEwjIrO-in_fjAhVmw8QBHYKACj0Q4dUDCAo&uact=5

    It might be a good idea to put up a warning NOT to use Loctite 243 on the panel nuts/screws in the docs!

    Edit: i’ve spread around some Weicon threadlocker on the edge of one of the panels (they’re ruined anyway) to see if that has the same effect or if Weicon is safe to use. Will update in 24-48 hours.
     
    #8 orcinus, Aug 10, 2019
    Last edited: Aug 10, 2019
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  9. Jonas

    Jonas Well-Known Member

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    Thanks for highlighting this for the rest of us!

    Jonas
     
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  10. orcinus

    orcinus Well-Known Member

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    Jesus christ this thing acts fast…

    This is after only 8 hours:

    [​IMG]

    And this is Weicon:

    [​IMG]

    Slightly better than Loctite, but you can see it just about starting to develop cracks and seeping in.
    Bottom line: don’t use *any* threadlocker, or if you use one, test it out for 24 hours on a piece of scrap (the circular cutouts for the extruders should work nicely).

    The original cracks around the screw holes, meanwhile, have continued to spread, and are now 5cm long in some places. And they’re all blue-hued, i.e. the 243 continues to seep and spread along them.
     
  11. Greg Holloway

    Greg Holloway Administrator
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    I have updated the docs. We shall arrange a set of replacement panels to be sent out to you!
     
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  12. blarbles

    blarbles Well-Known Member

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    Same thing happened to my panels - all are cracked around the screw holes and I barely hand tightened them.

    I used 242. Wish I had read this first.
     
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  13. jfb

    jfb Well-Known Member

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    Really glad I've seen this thread - I certainly didn't know about the effect of 242 (and similar) on plastics. Thanks for posting.
     
  14. jfb

    jfb Well-Known Member

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    @Greg Holloway just had a quick look at the docs and they still recommend using thread lock on the electronics panel - does that need updating too?
     
  15. Greg Holloway

    Greg Holloway Administrator
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    yes, i must have missed it.....
     
  16. Greg Holloway

    Greg Holloway Administrator
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    can you link me to the step where it says it. i can't find it....
     
  17. orcinus

    orcinus Well-Known Member

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  18. Greg Holloway

    Greg Holloway Administrator
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  19. blarbles

    blarbles Well-Known Member

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    @Greg Holloway So am I eligible for replacement panels too since I was following the instructions before you fixed them?
     
  20. Krayn

    Krayn Well-Known Member

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    So I was a bit lucky with this. When I started building my machine this earlier this week I was a bit impatient to get started and so I didn't thread lock any of the external acrylic panel bolts. I didn't have thread lock on hand, and figured those were easy enough to thread lock later. I ended up picking up thread lock about half way into the build once I got into the mechanical bits that actually run the machine. This means the only cracks that ended up developing are all on the rear panel that the electronics mount to.

    [​IMG]
    [​IMG]
    Essentially cracks where blue threadlock was used. It's a good thing I found this thread as I wasn't far from adding thread lock on the remaining external panels.
     

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