Protecting Your Time Capsule Items
As long as you are going through the effort of preparing a secure Geocapsule, you’ll want to make sure your efforts are not wasted over the course of a multi-month or multi-year hibernation. So protecting your time capsule items is very important.
There are 5 levels of protection that we recommended for above ground Geocapsule packages:
- The exterior rock (or log) housing
- Protective, unsealed polyethylene bags that enclose organic items placed in the time capsule
- The stainless steel capsule itself
- Separate poly freezer bags for capsule items
- Archival paper, archival pens, and special air conditioning packs for the capsule enclosure
Your Time Capsule’s Internal Environment:
Remember that if your time capsule adventure expects a retrieval in only a few months or years, a smaller thermos or vacuum jar will suffice. This still assumes it is protected under a Geocapsule or hollow rock/log. But a fully stainless steel time capsule is necessary for an extended retrieval time. That enclosure is discussed more on the Selecting Your Time Capsule page.
Regardless of your capsule’s size, you must also protect its contents. This is what to do.
Common Sense Rules:
Consider 1) environmental extremes and 2) length of placement when selecting your “keep-sake” articles. To avoid overheating of the Geocapsule’s internal space, you should seek a drop-site that is in constant shade. Weather extremes over multiple years, may affect capsule contents when stored above ground. Common sense solutions for these issues mean that you should:
-Choose practical items.
-Question how each item in your capsule may be affected by extremes of temperature.
-Never include liquids and never include food.
-Avoid gummed labels, and anything that could melt, leak, or deteriorate because of heat or cold.
-Avoid wool, silk and nylon fabrics
-Include no plants or vegetation
-Include no batteries
Preservation Kit Items:
In a small enclosure like your stainless capsule, deterioration of organic material accelerates with any intrusion of air (oxygen) and moisture (humidity). The following will control those problems.
Within each stainless steel or aluminum container, you should also insert a single packet of inexpensive silica gel (called a desiccant). This is sold in granular form in art supply and hardware stores. Desiccant buffers humidity that leaks into the container. It’s cheaper to buy this product over the counter than off the Internet, but a good alternative is to purchase it as part of a time capsule archivist kit. (See the Retailers page).
Over time, oxygen will speed the breakdown of organic materials, so you need to eliminate it. A commercial product called “Ageless” scavenges or sucks up oxygen that could leak into your capsule container. Ageless should be used in larger time capsule containers. (See Retailers page).
MVP Document Bags:
“Moisture-Vapor-Proof” bags (right) are high security sleeves for your photos, letters, papers and other keep-sake items. Your most valuable organic items should be inserted into this packaging, which is a combination of aluminum, poly and nylon material that keeps air and moisture out. These bags are also available in archival kits. (See Retailers page).
Heavy Duty Polyethylene Freezer Bags:
Some wood, paper, newsprint, or petroleum residues that accompany your small treasures into the tight capsule enclosure can expel light gasses and acids. Over time, colors from fabrics, paints and wood can “bleed” into other articles. So you’ll want to separate each group of organic items into multiple polyethylene freezer bags. Keep them unsealed so air -pressure does not build.
Acid Free Paper:
Standard paper that has not had its acidity neutralized will yellow and deteriorate over time. In the small capsule container, that process accelerates. So special acid-free archival paper (available from office supply stores) is recommended to ensure its survival over time. Archival approved gel pens are also recommended for writing. The gel ink in these writing tools will not fade inside the capsule.
Will your long term time capsule survive without these special additions. Possibly. But weigh the surviving value and importance of your capsule items when deciding to follow or ignore the recommendations.
For other details the Minnesota Historical Society has prepared a PDF download that will support the above information and give other suggestions.
Next Page: Time Capsules Underground