I’m prepping for building a quiet, windproof puffy. I’ll be using a breathable inner layer and Apex insulation. But for the outer fabric I want it to be as windproof as possible, still have some amount of breathability (think gore windstopper), be as lightweight as possible but also quiet. A tough list of boxes to check.
I’ve ordered a bunch of fabric swatches and samples for 1) WPB fabrics 2) softshell fabrics 3) calendared nylon/poly in various weights.
For ballparking the wind resistance, I plan on at least starting with a breath test. To pass, I ideally want to turn blue in the face before I can push any air through. Noise and weight are pretty self explanatory for testing.
But what’s the best way to ballpark the breathability? It doesn’t need to be very breathable, since it’s a static piece, but if there is any sort of moisture that does develop inside, I don’t want it to just condense on the inside of the outer shell and in the insulation. I’ve seen the “air pump” tests with the water column on YouTube, but as I understand that’s a test for air permeability, not breathability.
Can I just rubberband a fabric swatch over a glass tube with water and place it over a burner, as a pass/fail for if steam is able to escape through? I’m open to suggestions.

