Appendices To Manual > E - Sieve Set Construction Manual

Sieve Set Construction Manual BioSand Water Filter Humanitarian Service Last Revised: March 2005 BUILD A SIEVE Estimated Time: 30 minutes per sieve Tools Needed: • •

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Hammer Nails Saw Tape measure ½” staples (if readily available) 1” x 1” wood strapping

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1” x 4” timber (or whatever is locally available) ½” (2 gauge) screen ¼” (4 gauge) screen - 5 gauge is also acceptable mosquito mesh (14 gauge screen)

Note: The gauge indicates the number of slots per inch, so 4 gauge screen would have 4 slots per inch. Screens must be metal, not nylon or fiberglass.

1. Construct a square frame for the sieve.

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The suggested size is 18” x 24” (45cm x 60cm). This size is intended for use by two people.

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A smaller sieve can be constructed if only one person will be holding it.

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Other sizes may be constructed depending on the material available and the preference of the users.

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A group in Brazil suspended their sieves from ropes so that they don’t have to hold the weight of the media; they only have to shake the sieve.

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The two longer sides can be made longer than 24” to form handles.

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Don’t make the sieve so large that it is too heavy to hold when filled with media, or that the weight of the media deforms the screen.

2. Cut a piece of screen that is larger than the frame, so that there is 1” extra on all sides. 3. Centre the screen over the frame. Tip: For the mosquito mesh screen it is necessary to add a piece of ½” screen for support. Place the mosquito mesh on the frame first, followed by a piece of ½” screen the same size, so that when you flip the sieve over and use it, the ½” screen will be underneath the mosquito mesh, supporting it.

4. Nail staples through the screen and into the frame on all 4 sides. If staples aren’t available, pound a nail in halfway, and then bend it over and pound it into the frame.

5. Bend the excess screen back on itself so that the bent edge lines up with the outside of the frame, and the excess overlaps the rest of the screen. Doing so avoids sharp edges that could cut your hands while sieving.

6. Cut the 1” x 1” wood strapping to the same lengths as your frame to form a covering frame.

7. Nail the covering frame over top of where you’ve nailed the screen to the frame.

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8. Repeat the process until you have three sieves, each with a different screen size: ½”, ¼” and 14 gauge.

NOTES •

A well-built sieve will last for a long time so it’s worth taking the time to build it well and make it comfortable to use.

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Never use a sieve that has ANY holes in the screen or where the screen is separating from the frame.

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When the screen wears out, simply remove the wood strapping, pull off the old screen and attach a new piece of screen to the existing frame.

#12, 2916 – 5th Ave N.E. Calgary, Alberta, Canada T2A 6K4 Telephone: (403) 243-3285 Fax: (403) 243-6199 Email: [email protected] Website: www.cawst.org

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