Costs - Keep it Simple |
 In
Kenya in 1997, I produced 300 Nzi traps as a
practical demonstration of a "cottage industry" for small-scale
trap production. Traps
were produced on foot pedal sewing machines using
informal labour, and locally-available materials.
This is how traps are still typically made in Africa (Newsletter No. 5 at
BIOVISION) |
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Total cost with a
bottle or bag collector, including all labour, sundries,
and purchase of two sewing machines, was
US$7-9. These very low costs were possible only through wholesale purchases,
and do not include the costs of support poles (sapling trees are cut in Africa, no inner poles are used for the corner sleeves).
I have provided representative estimates of basic retail costs of
materials for North America in an EXCEL spreadsheet below . These prices are for direct "consumer" purchases,
and do not include duty, taxes, mail order charges, etc. The retail cost of an economical cloth trap in North America is about US$25 (+ sundries). Traps made out of higher-quality netting and optimal outdoor fabrics (Sunbrella) cost more (US$33), but will perform much better, and will last much longer. Although not always readily-available in the specific blues required for traps, purchase of "seconds" of hi-tech fabrics such as Sunbrella acrylic or Top Notch polyester is possible, and can greatly reduce costs. A robust alternative to a cloth trap is a relatively permanent painted plywood or plexiglass trap. My experimental plywood traps have special features and cost about US$70. A more basic format costs about US$50. Plexiglass traps are more expensive, but have the advantage of not having to be repainted. I have been testing both of these fixed formats for several years and have had good results relative to standard cloth traps. |
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It is easy to
dye cotton a bluish-green or turquoise shade equivalent to phthalogen blue with
sulphonated copper phthalocyanine reactive dyes. Unfortunately, the
results are not as colour fast as needed for prolonged outdoor use. |
