Low-Cost Foam Spray Marker

Low-Cost Foam Spray Marker SPRAYING Accessories 18-3-34 A number of years ago FARM SHOW ran a story about how to make a low-cost foam spray marker using cans of shaving cream. As I remember it, you could build this "Poor Man's" foam marker for less than $3. Could you provide details about it? (Bob Bettenhausen, Rt. 1, Streeter, Ill 61364) Editor's Note: USDA researchers came up with the idea, which we ran in FARM SHOW's Vol. 7, No. 3, 1983 issue. It's ideal for farmers who don't have large acreages to spray, and consists simply of a can of shaving cream mounted in a piece of PVC pipe on the end of the boom. Here's how it works: Depending on boom length, one can should last for 8 to 10 acres, applying a blob of foam every 30 to 50ft. To make the marker, you start with a 7 1/2 in. long piece of 3-in. dia. PVC pipe which holds the can. The tricky part is making the trigger which presses down on the shaving cream can button. Cut out a 3-in. wide, 4-in. section from another piece of 3-in. dia. plastic pipe, and fashion it into a "T" shape. The firing pin, or top of the "T", should be about 1/4-in. long (see photo). The trigger sits inside the top of the 3-in. pipe and is held in place by a nail that goes through the arms of the "T" and the pipe. The trigger arms should be beveled slightly to fit against the inside of the pipe. It's important to center the firing pin over the top of the shaving cream can but to have the nail, the trigger's pivot point, slightly off center so when the trigger is pulled, the firing pin presses down on the button. After fitting the trigger, place the shaving cream can in the pipe and drill a hole for a nail to fit through on the bottom of the pipe at the proper height to make contact with the firing pin. You can drill a small hole through this nail and insert a safety pin so it's quick and easy to remove the nail to insert a new can of shaving cream. Next, cut a notch in the top of the pipe to make room for a 3/16-in. dia. plastic tube extension that connects to the can's nozzle. The tubing can be cut to any length as long as It gets the foam out of the marker. On windy days, you may want to use a longer length of tubing to drop the foam nearer the ground. To increase the size of the foam blob, you can split the tubing at the end and insert a small funnel. The final step is to run a length of cord from the top of the trigger to the tractor. When you want to drop a blob of foam, just pull the rope. The marker attaches to the spray boom with a pair of hose clamps that run through two slits cut in the back side of the PVC pipe.

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