I’m wondering if it’s possible to 3D print or cast and mold (@seanhagen) a threaded adapter for a water faucet.
A friend has a water filtration appliance that is meant to hook up to the end of her kitchen sink, but she has an unusual pull-out spray faucet with threads that don’t fit any of the provided adapters. Home Depot and Canadian Tire both say that they have nothing in that size, and concluded that her only option is to buy a new kitchen faucet.
I think PLA is out of the question, as we can’t have it melting from the hot water. I don’t know if ABS would hold up (and not contaminate), and if it could be made water tight. Casting and molding an adapter is another option, but I also have no knowledge of the material properties and food safety of standard resins. Any information or suggestions are appreciated!
On Wikipedia, they state that PLA has “a glass transition temperature 60–65 °C, a melting temperature 173–178 °C,” and “Due to PLA’s relatively low glass transition temperature, PLA cups cannot hold hot liquids.” If you can confirm that this does not apply to 3D printed objects, I would like to know.
The thread size is something around 7/8"-15/16". I only had a tape measure on hand so I don’t know exactly what it was. Would you need a tap and die set even for a 3D printed part? I worry that it will be similarly difficult to find the right tap and die for this faucet.
You could definitely mold and cast something like that ( although I’d want to see the part in person just to make sure ).
As far as food safe, I think it should be fine – most of the Smooth-On resins can be baked for a few hours at ~170 degrees to fully cure them. I think after that it’d be fine. I’m going to email the Smooth-On folks to make sure, though.
I know that resins can be food-safe – wood is coated with epoxy resins all the time for food applications.
The biggest issue with printing will be that 3D printed objects have lots of little crevices to trap bacteria and PLA will definitely not stand up to the dishwasher.
@seanhagen, thanks for the info and for looking into it with Smooth-On. The threaded parts are pretty standard-looking, and I could probably borrow them for an evening if I give my friend some notice.
Thank you for contacting Smooth-On with your inquiry. Our materials are designed and primarily used for mold making and casting. We do not have a product recommendation for the application that you describe. Properly cured parts cast from TASK® 11 urethane plastic resin is suitable for some FDA/USDA applications but for dry food contact only.
It will be up to you as the user to determine the suitability of our products for your application. We always recommend doing a small scale material test before using our products for a critical project or application.
I do have a faucet attachment that I get plenty of use out of but its not for same purpose you want. Almost all hot water from taps are below the 60C level. That can burn people quite easily. I think mine is at 55C but that’s pretty high. Yes needs to be cleaned and dishwasher is a bad idea. But I use a cleaning agent meant for cleaning and sterilizing wine equipment so that works fine on 3d printed parts
