<p>I printed a G1/8 thread in PLA where I can connect a compressor to have a small pressure container. Even though all measurements are correct and it screws in fine, it still leaks air.</p>
<p>Is there a way to make 3D prints airtight?</p>

[{'answer_id': 19542, 'author': 'iblue', 'author_id': 34449, 'author_profile': 'https://3dprinting.stackexchange.com/users/34449', 'pm_score': 2, 'selected': False, 'text': '<p>Yes.</p>\n<p>The issue is, that there are small gaps between the layers. But you can coat the print in an airtight material. While epoxy and similar materials work very well, they are somewhat too viscous and take a long time to cure.</p>\n<p>My special recipe for coating PLA prints with a fast-curing airtight thin layer is:</p>\n<ol>\n<li>Dissolve 1 g Paraloid B-72 in 20 ml acetone.</li>\n<li>Dip or otherwise evenly coat the print and dry at room temperature for 10-20 minutes.</li>\n</ol>\n'}, {'answer_id': 19543, 'author': 'R.. GitHub STOP HELPING ICE', 'author_id': 11157, 'author_profile': 'https://3dprinting.stackexchange.com/users/11157', 'pm_score': 2, 'selected': False, 'text': "<p>In theory, yes you can without any additional materials. But it requires a very high level of perfection for your 3D printer's output.</p>\n<p>&quot;Gaps between layers&quot; are not the issue. There is no &quot;gap&quot; between the extrusion at layer N and an identical-path extrusion at layer N+1 if layer N+1 is extruded correctly and remelts the surface of layer N sufficiently to bond everywhere. There are <em>grooves</em> between layers from the extrusions not having perfectly rectangular cross-section and rather slighty rounded edges, but these are not &quot;gaps&quot;.</p>\n<p>Where gaps do come in to play is from inconsistent extrusion. If at any point the printer fails to resume extrusion where it's supposed to, or extrudes slightly less material than it's supposed to, there's a possibility that the complete remelt/bonding described above does not happen. It's also possible that grooves <em>turn into gaps</em> under high pressure, by providing a surface where the pressure can act like a wedge to separate weakly-bonded layers.</p>\n<p>Also involved here are issues with the filament quality. If the filament contains air pockets or has absorbed moisture, there will be tiny bubbles bursting in the extrusions, making a potential path for air to pass through.</p>\n<p>I have not succeeded in producing an air-tight container, especially not at high pressure, but I have made test containers for a vacuum that take several minutes to return to ambient atmospheric pressure after the pump is removed. This was using PLA with a non-high-temperature-capable hotend. I'm planning on revisiting this at some point with the temperature cranked way up (now with all-metal) with PLA and other materials to see if there's any practical viability to the theoretical possibility of getting it right.</p>\n<p>Short of that, iblue's answer to use an airtight coating is a great option if you can deal with the dimensional changes or compensate for them in designing your parts.</p>\n"}]
['https://3dprinting.stackexchange.com/questions/19541', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/34449/']