MARKING DEVICE

Paint Marker Device

Project Driver:

A liquid marker offers a durable marking which cannot blow away and, if the paint is chosen well, will bind sand, leaves, grass etc. to create a "caked" mark which cannot easily be mistaken or misplaced.

This picture shows an Afghan deminer using a Schiebel metal detector. Note the red and white painted rocks in the background. A paint marker could greatly reduce the time and effort needed to mark the ground when large areas are searched with few targets. Accidents have occurred because deminers rely on visual memory to mark the ground they have searched. (See minefield tour of Cambodia for completely different techniques used there)

Grass marked with paint

Left: spray head (left side)

Centre: spray head (right side)

Right: handle and trigger

These pictures show an experimental paint marker developed at UWA by James Trevelyan and tested later in Pakistan with satisfactory results.

The marker uses acrylic paint, diluted with water, which is pumped from a spray bottle head (cost approx $1) attached to the rod of a metal detector. A small reservoir holds enough paint for about 150 squirts. The spray head is activated by a handle near the metal detector hand rest which pulls a cord, activating the lever at the spray head.

Important Details

1) A small plastic part attached to the lever at the spray head covers the paint nozzle when the trigger is not being pulled. This prevents the nozzle from drying out and hence blocking the spray head. We tested this by leaving the spray head unused (with paint of course) for 1 hour, 2 hours and 4 hours with daytime temperature of about 38 degrees Celsius (approx 100 F). There were no problems.

2. Fine stainless steel mesh screen filters are essential in the inlet tube, and, for convenience, in the tube used to fill the paint reservoir.

3. The paint reservoir is designed so that deminers can have several in their pockets in case they run out. The paint reservoir should be easily changeable.

4. The spray head needs to be cleaned at the end of each day using water.

5. A specially designed reservoir filling set-up and spray head cleaning set-up would be essential for practical operation in the field.

Left: close up of grass marked with white paint, right: larger area marked with many spots.

Cost estimates:

These are not available at the present time, but the final cost is expected to be below A$5 per unit for materials

Further Work:

Awaiting reactions and comments from deminers.

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All graphics by Demining Research Team. Aug 1998.
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