3D Printed Chain Mail Armor: Failure Analysis

While dropping some recent 3D printed odds-n-ends into the show-n-tell box, I discovered the large sheet of square chain mail armor had a missing link:

Chain Mail Armor - the missing link
Chain Mail Armor – the missing link

Fortunately, the link fell off in the box and I recovered all the pieces for a failure analysis:

Chain Mail Armor - failed link - glue spots
Chain Mail Armor – failed link – glue spots

I’d glued the PLA together with IPS #4, a hellish mixture of plastic solvents including methylene chloride, one of the few chemicals able to chew into PLA, but there’s not much penetration or bonding going on.

Let’s try that again with a bit more solvent.

First, slide the bars into place:

Chain Mail Armor - failed link - bars in place
Chain Mail Armor – failed link – bars in place

I applied four solvent drops in two passes to give it time to work its way in, put four matching drops on the armor cap, squished the cap in place, tweaked the bar alignment, then applied pressure while contemplating the whichness of the why for half a minute while the solvent worked its magic.

Things look pretty good once more:

Chain Mail Armor - missing link - repaired
Chain Mail Armor – missing link – repaired

There’s no way to determine the repair’s goodness, other than by deliberately trying to snap off a bar, so I’ll just put it back in the box and hope for the best.

5 thoughts on “3D Printed Chain Mail Armor: Failure Analysis

  1. I sense a test jig, samples, tabulated measurement results and graphs coming on :)

  2. I got curious since the ePlastics site doesn’t mention PLA specifically, so I asked them what they’d recommend for gluing it, and they replied that IPS 16 is suitable.

    1. Looks like it’s MEK + dichloromethane, so, yeah, it’ll get the job done. Phew!

  3. Didn’t we have this conversation about CH2Cl2 vs THF oh, about six years agi? :)

    1. Around the time I was busy figuring out how to do chain mail without glue? Sounds about right … [grin]

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