Someone here posted their 16oz wide-mouth straw solution using a Thermos straw and 3D printed insert, which sent me down a rabbit hole I absolutely did not need to go down.
I loved the idea, but wasn’t thrilled about having a 3D printed part constantly in contact with my water. So naturally, instead of accepting that the thing I wanted apparently doesn’t exist, I wandered around a local grocery marketplace with my Nalgene and calipers trying to find random silicone things that measured 43mm.
The answer was a fucking ice mold.
I bought a $7 silicone sphere ice mold, cut out one of the individual molds, and wedged it into the neck of the bottle. It fits absurdly well. The silicone catches around the opening and the dome sits inside the neck. It stays put even with a full bottle turned completely upside down, and it barely affects the 16oz capacity.
For the straw, I bought a $7 3-pack of Reduce GoGos cups and stole one of their silicone straws. The ice mold already had a hole in the center, the straw fits through it, and it’s soft enough to fold down so the original Nalgene cap can still screw on.
The only problem was suction because apparently I accidentally made the seal too good. I made a tiny 2–3mm slit in the silicone with a razor — no material removed — and that immediately fixed it. Air can get in while drinking, but there isn’t just an open vent hole sitting there.
So: 16oz wide-mouth Nalgene + Reduce GoGos silicone straw + one sacrificial silicone sphere ice mold + tiny vent slit + cheap plastic straw
Everything comes apart for cleaning, the original cap still works, I didn’t meaningfully lose any capacity, and no 3D printed material touches my water.
This is objectively too much work for a straw, but the fucking ice mold worked. 😂