PC water cooling 90 degree elbows

Low-Profile 90° GPU Cooling Elbows

I thought i'd share these with the community since i didn't find much watercooling options out there to 3D print. I had a lot of trial and error to get these to be leak free. These are custom-designed low-profile 90-degree elbows made for a GPU water-cooling project where space is limited and standard fittings are too tall. The design is intended to help route tubing cleanly in tight GPU/multi-GPU setups while keeping the overall height as low as possible.

The elbows were printed in ABS for improved heat resistance. After printing, the parts should first be test-fitted and checked carefully for alignment, clearance, and sealing surfaces. Once fitment has been confirmed, the parts can be acetone vapor smoothed to improve layer bonding, surface finish, and water resistance. Just don't overdo it since the threads will "melt" away. Let the prints cure for some time after the vapor chamber, guides says this:

For ABS acetone vapor smoothing, I would wait:

Minimum handling: 1–2 hours
After removing from the chamber, let the surface flash off. It may still be soft, so do not press sealing surfaces or O-ring grooves yet.

Fitment / light assembly: 12–24 hours
The part should feel dry and no longer tacky. Still avoid fully tightening fittings if the part feels rubbery or smells strongly of acetone.

Before leak testing with water: 48–72 hours minimum
For water-cooling parts, I would wait at least 2–3 days so the acetone has evaporated deeper from the plastic and the ABS has hardened again.

Before installing near GPUs/electronics: ideally 5–7 days
Since these are custom water-cooling fittings, I would be conservative. Let them cure for about a week, then do a proper pressure/leak test outside the PC.

Rule of thumb: if it still smells like acetone, it is not fully cured.

Also remember that acetone vapor smoothing can slightly change dimensions. So check the O-ring grooves, sealing faces, and screw holes again after curing, not only before vapor smoothing.

Another options is clear coating the parts, but i find that option very tedious...

Use O-rings with a cross-section/thickness that matches the O-ring groove size as closely as possible. The O-ring should sit neatly inside the groove without being loose, pinched, or forced in. The O-ring thickness should be approximately as large as the groove it is designed for, so that it compresses properly when assembled and creates a watertight seal.

Important safety note: 3D-printed water-cooling fittings should not be considered as reliable as machined or commercial fittings. Plastic can expand, move, soften, or deform slightly with heat, and if coolant temperatures get too high, the fittings may lose O-ring compression or change shape enough to start leaking. Use these parts only in experimental/custom builds, and always pressure-test and leak-test the loop before running it near electronics.

Recommended workflow:

1. Print in ABS.

2. Check fitment on the GPU/project assembly.

3. Verify clearances and sealing areas.

4. Choose O-rings with a thickness matching the groove size.

5. Acetone vapor smooth only after fitment is confirmed.

6. Pressure/leak test before using near electronics.

7. Monitor coolant temperatures carefully during use.

These parts are intended for custom PC cooling/modding use and should be tested carefully before being installed in a live system. Since 3D-printed parts can vary depending on printer settings, material quality, post-processing, and coolant temperature, leak testing is mandatory.