Does anyone know if there are there any hydrophobic filaments or resins in the market? I have a part I need to make that can’t be allowed to stay wet and it would be better if we didn’t have to get it coated
I seem to remember reading somebody made a nylon that was designed to be hydrophobic and therefore no drying and easier to print. I am struggling to remember, whom it was.
Well thanks, your description led to this but I don’t think its really what I’m looking for. They only claim is slows water absorption.
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Yes that is what i was thinking. I was on the ferry and looking things up on the phone is a pita. Sorry I can’t recall anything else.
Hi Glen
Here are a couple of pieces of info I found, Looks like PolyProp is what you are looking for, I cannot find a filament in our inventory that says “PP” maybe if @Aman_Bains happens to see this thread he can comment. He is literally the expert in this field. Sorry Aman don’t mean to throw you under the bus, 
PP
PP is a thermoplastic 3D filament that is commonly used for creating food packaging, bottles, and containers. It is very lightweight, but don’t let this fool you. Whereas other materials absorb water over time, PP is hydrophobic, meaning it will repel water.
If your print needs to be watertight, PP is a good choice due to its flexibility and interlayer adhesion. This means it does not produce many gaps or holes in between layers when printing.
Along with being waterproof, it is highly resistant to other substances including aggressive chemicals such as alkali, acids, and organic solvents. In fact, PP is one of the strongest chemical-resistant 3D printing materials. It is also flexible and has good heat resistance.
PP GF30
If you need your 3D print to be weatherproof, then PP GF30 (Polypropylene 30% glass fibre) will be a great option. This 3D filament is not only waterproof, but it is resistant to highly aggressive environments, including high heat, UV, and chemicals.
The difference between PP GF30 and PP is the extra 30% glass fibre that is filled into the filament. This glass fibre allows PP GF30 to stay lightweight and water-resistant while adding in a bit of extra strength and rigidity. PP GF30 is commonly used in the automotive and aerospace industry.
All 3D has an article about it, but even in the article, they talk about storing it in a Dry Place. They ref because of the additives but does make you think
Interesting I just skimmed it. Ill follow up later. Back to back zooms today 
One note. it says to use clear packing tape because pp likes to stick to pp which is true but packing tape has release coat on it that will prevent it touching.
Hi Glenn
Can I learn a little more about your application?
Aman
Hi Aman
I have to make a small chamber that has a reservoir at the bottom that will have some water maintained inside and will be atomized in the empty space above in operation. the goal is to wet a material that is flowing by but when the material is not present I want the upper (inside) surfaces to reject water so whatever water that winds up there needs to flow off completely. In the design, I have a metal cover up there and have investigated a coating that will work but if I can use a filament that already has these properties to make this piece it would last longer and make a better part. PET and PP don’t really absorb water but they do not on their own reject water, there is still a bond there and the surface can stay wet until it evaporates, in some cases.