Waterproof product design is one of those things that looks simple on a render and gets hard the moment a prototype goes into a bucket of water. Outdoor electronics, marine gear, handheld tools, lighting, and wearables all need housings that keep water and dust out while still opening for assembly, charging, and service. At eCadCam in Los Angeles, we have found that most enclosure leaks trace back to a few early design decisions. Here is how we approach them.
Start With the IP Rating Your Waterproof Product Actually Needs
Before modeling anything, decide what “waterproof” means for your product. The most common yardstick is the IP (Ingress Protection) code defined in IEC 60529. It has two digits: the first covers solids and dust (0 to 6), the second covers water (0 to 9).
- IPX4 – protected against splashing water from any direction. Typical for outdoor fixtures and many consumer devices used in the rain.
- IP65 / IP66 – dust-tight and protected against water jets. Common for industrial controls, enclosures that get hosed down, and outdoor equipment.
- IP67 – dust-tight and protected against temporary immersion (the standard test is 1 meter for 30 minutes).
- IP68 – continuous immersion beyond IP67, under conditions the manufacturer specifies (depth and duration).
Pick the lowest rating that genuinely fits the use case. Every step up adds sealing features, tighter tolerances, more expensive tooling, and more testing. A garden light rarely needs IP68; a dive accessory absolutely does. If you plan to claim a rating on packaging, budget for third-party testing too.
Sealing Methods in Waterproof Enclosure Design
Once the target is clear, we choose how each joint will be sealed. Most products combine several of these:
O-Ring Face and Radial Seals
O-rings are inexpensive, reliable, and well documented. A face seal sits in a groove on a flat flange and is compressed when the halves are screwed together; a radial seal sits around a bore or plug, which works well for caps and round housings. The groove geometry is what makes or breaks the seal. We size grooves from the O-ring supplier’s published guidelines for squeeze and gland fill, rather than guessing, and leave room for the ring to expand with temperature.
Gaskets and Formed-in-Place Seals
For large or irregular perimeters, a die-cut or molded gasket is often easier than an O-ring groove. Formed-in-place (dispensed) gaskets are another option for production runs. In CAD we design a defined compression stop so the gasket is squeezed by a controlled amount instead of crushed.
Overmolding and Potting
Some parts never need to open. Overmolding a TPE skin over a rigid core, or potting electronics in resin, can eliminate seams entirely. The tradeoff is serviceability: a potted board cannot be repaired.
Ultrasonic Welding and Adhesive Bonding
Permanently sealed housings can be ultrasonically welded or bonded. Weld joints need specific energy-director or shear-joint geometry designed into the part from the beginning.
CAD Details That Prevent Leaks
The seal itself is only part of the story. These design details matter just as much:
- Stiff flanges and enough fasteners. A thin flange flexes between screws and opens gaps. We add ribs and space screws so compression stays even around the perimeter.
- Continuous sealing paths. The seal line should never be interrupted by a screw boss, a parting line, or a sharp corner. Generous corner radii help O-rings and gaskets seat properly.
- Buttons, ports, and cable entries. Every opening is a leak path. Membrane switches, sealed connectors, cable glands, and silicone keypads each need their own sealing strategy.
- Pressure equalization. Sealed housings breathe as temperature changes, which can pull water past a seal. A breathable membrane vent lets air move while blocking liquid.
- Material and surface finish. Seal surfaces need to be smooth and flat. Sink marks from injection molding or layer lines from a 3D print can create leak paths, so we keep sealing faces away from thick sections and specify finish where it matters.
- Tolerance stack-up. Compression depends on several dimensions adding up correctly. We check the worst-case stack so the seal still works at both ends of the tolerance range.
Prototyping and Testing a Waterproof Design
We recommend prototyping seals early. SLA and PolyJet prints are useful for checking fit and groove geometry, and simple dunk or spray tests on prototypes catch most problems before tooling money is spent. Keep in mind that printed parts can be slightly porous or less flat than molded ones, so a prototype that leaks is not always a design failure. We also design with the final production process in mind, whether that is injection molding, CNC machining, or low-volume 3D printing, because each affects flatness, draft, and seal surface quality.
Get Help With Waterproof Product Design in Los Angeles
Whether you are sealing an outdoor sensor, a marine accessory, or a rugged handheld device, our team can take you from concept through sealed-enclosure CAD, prototypes, and manufacturing-ready files. With more than 22 years of experience, eCadCam handles product design and CAD, 3D printing, and 3D scanning under one roof. Request a quote today: call us at 213.489.1173 or visit our studio at 4212 San Fernando Rd, Glendale, CA 91204.