I want to start this off by saying I do plan to do more thorough and scientific testing. But, we’re actually gearing up to move in a couple weeks. Since I’m reassembling some of the project guns I’ve been working on before the move with 3D printed parts, I wanted to have an answer beforehand.
My main question was whether or not 3D Printed Polymers will become weaker when exposed to lubricants and solvents used for firearms. I only have/print with PETG and PLA at the moment, so they’re the only two that’ll be tested. Later, I may also test nylon.
Setup was dead simple. I’ve been working on a bunch of 3D Printed follower designs for the Mossberg 500 I just acquired. This has left me with an abundance of nearly identical followers.
I simply took 2 of each type of polymer and submerged them in both gun oil and barrel cleaning solvent.
I also had several on hand that weren’t exposed and thus act as a control.
The parts were submerged for 12 hours before testing.
Then, I simply applied pressure on the sides of the followers until they cracked or split in half. The amount of pressure wasn’t recorded, but just by “feel”/hand. So super unscientific, but it should at least give some indication, especially if there’s significant degradation in the part.
You’ll have to forgive me, in that when I originally did the test I was only intending to do it for myself. It wasn’t till today when the parts were already tossed that I thought: “Oh, this would be great to share!” As a result there are no images.
Let’s start with the PLA. The PLA prints that were soaked did feel like they broke far easier than those which were not. The breaks also occurred cleanly along layer lines. When breaking the PLA prints that weren’t soaked, it felt like far more force was required, and they didn’t tend to break as cleanly, which is interesting. They tended to crush/deform before layer adhesion was broken. When layers did break apart from each other, it tended to not be one clean separation, but there’d be parts where additional layers held on.
The PETG prints didn’t seem to be adversely affected by the solvent or oil, both being too hard to crush with my fingers. This lines up well with a chart I found, which suggests PETG has a strong resistance to most chemicals and oils.
I don’t want to jump to conclusions on this without any more scientific input. But, this does seem to suggest that PLA might not hold up to long term exposure to gun oils. I’m putting these preliminary findings out, just to get the word out – as maybe someone else can test in a scientific manner before I can. (Please let me know if you do! I’d love to see the results!)
But, if nobody else takes a look into it, I’ll set up a more scientific testing method after I move, circling back around to this in maybe a months time.