Selecting Your Time Capsule



An above ground option (a hollow rock or hollow log Geocapsule with stainless container) should be considered when:

1. Your projected retrieval time may extend from days to years.
2. You feel confident about identifying a remote placement site where your Geocapsule can be totally camouflaged by the surrounding terrain and is invisible even to those who may come within feet of the cache.
3. Your internal Geocapsule items are few and have insignificant value beyond family.
4. Your internal Geocapsule items will be able to withstand environmental extremes if exposed over time.

To purchase either an above ground Geocapsule (i.e. hollow rock or log together with a stainless steel capsule) or a below ground stainless steel tube, retail costs are in the range of $75 to $150. This generally includes turn-key archiving materials and supporting documents.

Artificial Hollow Rock/Log Geocapsules


The Hollow Rock Alternative

We have been testing time capsule alternatives since 1999. Over that period, we have studied and rejected many options. We now feel the hollow rock and hollow log Geocapsules are your best above ground options for this adventure. We  do not sell them. We only offer manufacturer links on our Geocapsule Products page. The Geocapsule is a two piece set: a simulated rock or log, and the stainless steel capsule itself.

Material Advantage: Textured structural polyurethane provides a perfect camouflage as well as a durable long term shield for your stainless time capsule. Its hard framework has a granular exterior, and its natural character makes it virtually indistinguishable from millions of other small surface boulders whether viewed from close up or far away. For this very unique adventure, “indistinguishable” and “unremarkable” are words that define its splendid disguise.(Arrow below identifies the false rock.)

These 2–3 lb. housings are designed for strength, and security over many years of exposure to seasonal weather extremes. They are crafted to withstand wide ranges of hot/cold, freeze/thaw, UV rays and weather. And they are available in a range of natural earth tones, textures, styles and sizes.

Variations: Your choice of rock color should approximate that of your drop-site. A few regions have dominant earth tones like white sandstone or red rock in the southwest. In most areas however, a mixed light brown tone is a universal color.

As camouflage that neither despoils the environment nor attracts unwanted attention, the hollow-rock and hollow log Geocapsules succeed exceptionally well. (See various photo examples of hollow Geocapsule placements on the Geocapsule Photos page.)

Avoids Digging: The above ground Geocapsule choice confronts the most frequent opposition of those who have the heebie-jeebies about digging any hole in the ground, even if that activity is not proscribed. And it serves up an effortless opportunity to participate in a Geocapsuling experience.

These simulated natural housings are simply the best protective storage volume for securely concealing your time capsule.

 The Hollow Log Alternative

A larger artificial log housing will accept the longer (one foot long by three and a half inches in diameter) stainless steel capsule.



The simulated log is virtually identical to a real log. In fact, all the Geocapsules found on our Geocapsules page are exact duplications taken from life-molds of the real thing.




The exterior Geocapsule housing is only a first level of security for your capsule. Remember that you are not just disguising your cache; you need to add structured levels of security to ensure the content’s survival up to many years.


The Stainless Steel Time Capsule Insert

A stainless steel capsule is hidden underneath the artificial rock (or log) housing for complete camouflage. Stainless steel is the best protective container for your capsule items because it can be permanently sealed from oxygen and humidity intrusion. It will not rust, it is structurally sound and is well suited for this type of application.



Primary drawbacks to above ground time capsule placements relate to perceived risk of discovery or other environmental factors. These presumed risks are so minimal as to be inconsequential if your preparation and placement are well considered. See Choosing Your Drop Site for a broader consideration of these factors.  Spring-Capsule-Trek

Be realistic: If you want to preserve keep-sake items, you should lock them in a safe, not in a wilderness time capsule. Minimize risks as detailed in these pages and your high hopes for secure delivery to a future generation will succeed. That’s what this adventure is all about.

So choose the appropriate Geocapsule, seal your capsule containers as directed, select your drop sites with intelligence, and then expect with confidence that your small treasures will survive as intended.

For more detail on preparing the above ground, hollow rock and hollow log Geocapsules, see the page Protecting Your Time Capsule Items.

Pricing and Product Options: There are several artificial rock shapes, sizes and earth tones to choose from together with pre-assembled Archival Kits. You can link to manufacturers on our Geocapsule Products page. Prices depend on the size of the housing, and whether its an above or below ground selection.

Ammo Cans…Never Recommended


Er… No! As above-ground time capsules, U.S. military issue ammunition cans are neither sensible nor acceptable for Geocapsuling activities.  For short term scavenger hunts or for use in the sport of geocaching, these boxes may suffice (though we prefer hollow rocks or logs). But they’re visibly incongruous to any wilderness area so invite discovery. Since our retrieval time frames are usually longer than typical scavenger hunts we recommend more secure and more environmentally compatible options. Other commonly used containers for the sport of geocaching, like 5 gallon plastic buckets and Tupperware containers are also unsuitable housings for time capsules.


Time Capsule Options: Below Ground

Underground is not an option for almost any public property, unless…as an example…a municipality wants to bury a time capsule at City Hall. An underground time capsule (a stainless steel housing) can be considered when:

4-Stainless-Array1. You want near total internal and external security for your hidden capsule.
2. The projected retrieval may extend from 10 to 100 years.
3. You need to protect valuable items inside the secure container.
4. You are concerned about above ground exposure to weather elements over the years.
5. The terrain (also the land manager or private owner) allows for digging.
6. Your Geocapsule is probably going to be deposited on private land, or on public land as a cornerstone insert, or as an archived capsule for buildings or parks, or on other public land with permission from land managers.



The Stainless Steel Time Capsule…  Underground

Your underground options are most likely on private property, special permission placements on public property, backyard, or “back 40” choices. There may be other underground options we haven’t considered. Your best alternative for long term preservation underground is a non-rusting stainless steel housing that is well sealed and protected from environmental elements.

Long Term Survival: Stainless steel will survive to over 100 years. Cost for the stainless steel time capsule (without Geocapsule housing but with archivist kits) is in the $50 to $125 range.

Stainless steel containers have screw-on tops that are sealed with silicone.



The Plastic PVC Pipe Time Capsule…Not Recommended


PVC-PipeA four to six inch diameter PVC pipe with end caps sealed by silicone is a low cost choice for short periods of storage underground…but with reservation.

Inexpensive PVC, or polyvinyl chloride pipe, is the common plastic drain pipe you can buy at your local home center or hardware. The problem with this lightweight material is that it emits chemical vapors, which break down organic materials within a restrictive atmosphere. The small enclosed space of your time capsule will accelerate this biodegradation. PVC pipe can also crack if not buried deep enough to prevent freezing. So PVC housing material is never recommended by responsible archivists.

A Teeny But: You still might consider PVC pipe with the following caveats:

If your time capsule will be underground for a relatively short time, organic deterioration may be negligible. If the PVC pipe contains no perishable items like paper, soft wood, fabric, photos, or more fragile organic articles, then you may see little deterioration or damage. You could wrap or enclose items in heavy-duty polyethylene bags to inhibit the intrusion of destructive PVC vapors. But even polyethylene sleeves will not totally shield items from the gradual intrusion of harmful vapors.

So if you are planning for a future-generation’s time capsule retrieval many months or years away, you should avoid the PVC pipe option. And if you can’t be certain when your Geocapsule will be retrieved, without question it will be best to look at other, safer underground capsule housing choices.

Other Options? Are there alternative poly materials that could work well underground? Yes… and no. If sealed well, structural polyethylene, polypropylene and polyurethane (not PVC) are excellent long term time capsule housing materials without the negative consequences of PVC. These polymers last at least 50 years in wide extremes of temperature. But unfortunately, this piping material cannot be found at your local home improvement centers.

So, your best…and currently available…underground option remains the stainless steel tube as discussed above.


Military Ammunition Box for Underground Use…Never Recommended

An ammo box (or ammo can) should never be placed underground for use as a time capsule because over time the steel container will rust and its rubber seal virtually assures the invasion of water and humidity.  As a below ground container ammo boxes simply carry too much ecological risk, so they should be rejected in favor of much better and more secure alternatives.

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