Ultimate Waterproof Geocache Container

thingiverse

This is a waterproof 3D printable container designed for geocaches, but it also serves other purposes. The container seals with o-rings and has several features that limit water entry and keep the interior dry. Everything can be customized to create an optimal container for your specific needs. ## Features * All parameters are customizable, including the container size, number of sealing o-rings, text labels, etc. * Option to include multiple concentric seals for extra water resistance. * The design automatically determines which standard sizes of o-rings fit best with the chosen parameters and includes part numbers (o-ring "dash number") on the inside bottom of the container. * Optional exterior cap clips latch onto the container when closed and resist the cap from backing off due to vibration or weathering. * Inside the cap, a pocket with perforated material is included for desiccant such as silica gel. The pocket can be filled with whole silica gel packets in larger sizes or beads for smaller sizes. Even if no liquid water enters the container, humid air inside can condense when temperature drops. Including a desiccant mitigates this. * O-ring grooves have retaining clips and raised sections to form a better seal with the suboptimal surfaces FDM printing produces. * No overhangs greater than 45 degrees, including threads. ## Parts The container consists of two parts: The container body and the cap. An optional third part is the cap for the desiccant pocket (if included). The pre-made STLs include all the necessary parts. Using the customizer, individual parts can be selected. ## Pre-made STLs The customizer can create containers with custom specs, but the pre-made STLs included here cover a few common configurations. They are provided in 3 sizes (small, medium, large), with 1 or 2 o-rings, and with/without clips. If you're unsure which to choose, a good compromise is `medium-2seal-noclips`. Two o-rings provide a better seal but make the top of the container larger and require ordering an additional size of o-rings. Clips can help prevent the cap from backing off on its own, but can also be prone to snapping off in some circumstances and cause opening and closing to require more force. Here's a list of included sizes, dimensions, and which o-rings are needed for them. For 1-o-ring versions, only the smaller of the two o-rings is required. #### Small * Inner diameter: 25 mm * Inner height: 30 mm * O-ring numbers: #126 and #134 * McMaster part numbers: 2418T148 and 2418T153 #### Medium * Inner diameter: 50 mm * Inner height: 70 mm * O-ring numbers: #141 and #149 * McMaster part numbers: 2418T16 and 9452K156 #### Large * Inner diameter: 75 mm * Inner height: 100 mm * O-ring numbers: #151 and #153 * McMaster part numbers: 2418T18 and 9452K158 ## Material Selection The design automatically selects standard o-ring sizes that are available from many manufacturers. If rendering the design with OpenSCAD, the chosen sizes are printed to the console. I'm not sure how to view these when using the customizer, so the size numbers are also printed on the inside bottom of the container. **Sizes:** The design automatically selects standard o-ring sizes that are available from many manufacturers. **Durometer:** I recommend using soft o-rings (for example, durometer 50A) for better sealing on the rough 3D-printed surfaces. **Material:** A range of o-ring materials should work, but Buna-N is generally a pretty good choice. McMaster-Carr carries suitable o-rings that fit these specs under the category "Oil-Resistant Soft Buna-N O-Rings". ## Grease The sealing and functioning of this container can be improved by adding grease to a few spots: * Greasing the o-ring grooves and o-rings themselves can help seal small gaps in the 3D-printed layers surrounding the seals. It can also extend the lifetime of the o-rings. * Adding a small amount of grease to the main screw threads can help them operate smoothly. There should be no need to grease the desiccant pocket threads since they are not frequently operated, and the grease may interfere with the desiccant. * If using external clips, a small amount of grease can be added to the upper exterior surface of the container to decrease abrasion on the clips and help prevent them from snagging.