Thursday, March 22, 2007

Updated WAPI Page

To look at an updated version of this page, including the Stainless Steel WAPI, click here.

Thursday, July 28, 2005


Thank you for visiting our WAPI webpage. Hopefully there is everything you need to know about WAPI's and if you have any questions or are interesting in making or receiving WAPI's don't be afraid contact us.

Wednesday, July 27, 2005

What are WAPIs?

The reusable WAPI (Water Pasteurization Indicator) is a simple, low cost device containing a special soy wax that helps users determine when water has reached pasteurization temperatures. The wax melts at the same temperature as the water is pasteurized.

Disease-causing organisms in water and milk are killed by exposure to heat in a process know as pasteurization. Boiling is often recommended to achieve pasteurization. However, contaminated water and milk can be pasteurized at temperatures well below boiling, saving time and fuel.

Water heated to 149 degrees F (65 degrees C) for a short period of time is free from microbes, including E Coli, Rotaviruses, Giardia and Hepatitis A virus. At 160 degrees F (71 degrees C) milk and foods are pasteurized.

The WAPI can be used successfully over most fuel sources including wood, charcoal and gas. It also works especially well in conjunction with the solar cooker. With good sun, simple solar cookers can pasteurize water for a family at a rate of about one liter of water per hour.

Tuesday, July 26, 2005

Why make WAPIs?

The WAPI, a reusable Water Pasteurization Indicator is a simple, low cost device that can be used to determine when water has reached pasteurization temperatures.

The Importance of Pasteurization

Water related diseases are responsible for 80% of all illnesses and deaths in the developing world. An estimated 1.5 billion cases of diarrhea occur each year, resulting in the death of nearly 2 million children. Worldwide, about 1.3 billion people do not have access to safe drinking water, including nearly half of the population of sub-Sahara Africa.

Producing WAPIs and distributing them to families living in areas of the world where clean water is unavailable positively impacts world health.

Monday, July 25, 2005

Directions- How to use a WAPI

Using solar energy to pasteurize water


1. Pour water into a black pot or jar.
Thin metal pots are ideal. If necessary, pots and lids may be painted black on the outside, with flat, nontoxic latex paint. Glass jars, painted black on the outside, also work well. Lids should have a small hole in them or be loosely screwed on to release steam pressure. Tip: Place a vertical strip of tape on the jar before painting, then remove the tape leaving a space through which to view the WAPI

2. Place a WAPI, washer down and wax up, into the water with the end of the string outside of the pot or jar. The washer end of the WAPI should rest on the bottom of the pot or jar and the wax end should be higher. Replace the lid.

3. Orient the solar cooker as you would for cooking. In general, face your cooker easterly in the morning and westerly in the afternoon.

4. Set the pot or jar in the solar cooker. If using a panel-type solar cooker, such as the CooKit, you can speed the pasteurization by placing the pot or jar inside a clear, heat resistant plastic bag. Though a plastic bag is required for cooking in this type of cooker, it is often not necessary for pasteurizing.

5. Leave the cooker in a sunny place for a number of hours, reorienting if necessary. Allow at least one hour per liter of water.

6. When the WAPI wax melts and falls to the bottom of the WAPI, the water has been pasteurized. Even if the water has cooled by the time you check it, as long as the wax is at the bottom of the WAPI then pasteurization has occurred.

7. Allow the water to cool before drinking.

8. Keep the water covered until use to prevent recontamination.
Don’t let fingers or unclean objects touch clean water.

If you aren’t sure, re-pasteurize the water.

Sunday, July 24, 2005

How to make WAPIs?

WAPI--- Production Process and Materials

1. 3/8”outside diameter x 1/4” inside diameter poly carbonate tubing. Usually comes in 8 ft. lengths.
2. 4 pound test mono-filament fish line cut into 15” lengths.
3. 2 each washers .174”x.4375”x.32” flat, 18-8 ss. (#8 washer)
4. 1 each flat washer, 18-8ss, 3/8” IDx1”OD.
5. Myverol 18-06 K wax.

Production Process

Station 1 – Cut tubing into lengths of 2 1/2”. Use PVC pipe cutters (easiest)

Station 2 – Using a small propane torch, heat one tube end and crimp closed with pair of pliers and let cool.

Station 3 – Put wax inside tube ( about 3/8” of wax) and add large washer over non-crimped end.

Station 4 – Using the propane torch, heat opposite end of tube and crimp using pliers. Let cool.

Station 5 – Drill 1/32” diameter hole in each flattened end of tube.

Station 6 – Cut fish line to 15” lengths. Tie one small washer (3/8”OD) to one end of fish line. Thread this line through one end of the tube, up along side of tube, under and through the large washer, and through the hole at the opposite end of the tube.

Station 7 – Tie a small washer (3/8” OD) at opposite end of fish line.

Station 8 – Insert instruction and WAPI into plastic bag (6 1/2”x3 1/4”). Snack bag.

Monday, July 18, 2005


Who to contact?

Is your club or organization interested in making WAPI's?
Would you or your organization like to donate funds so that others can purchaxe materials to make WAPI's?
Are you interested in receiving WAPI's?
Do you just have questions?

You can reach us at solarwapi@yahoo.com
We'd love to hear from you.

Where to find supplies?

The following suppliers were used for materials:
1. Washers – Fastenal Corp., 5358 N. Barcus, Fresno, CA. 93722, 550-271-3006.
2. Fish line – any sporting goods store.
3. Tubing – U.S. Plastic Corp., 1390 Neubrecht Rd., Lima, Ohio 45801, 1-800-537-9724.
4. Wax – Mitsubishi International Food Ingredients, 1-800-287-9989 (Customer Service line) Ask for your local rep.
5. Snack bag – any super market.
6. Instructions. We will send a copy to you. From there find the cheapest place that prints. We had ours done at a local middle school but we supplied the paper.

We would be happy to come out and show you how to build and package.