A correctly-sintered SLS or MJF part (printed in PA 12) will have some inherent water resistance, and you can apply coatings to enhance this. Silicones and vinyl-acrylates likely provide the best results, while polyurethane is not recommended for waterproofing. If you’re going for complete water resistance, we recommend a dip coating method. As well, an MJF part with a wall thickness over 4 mm is inherently watertight.