Spray Can for Garden Use. http://www.durgan.org/URL/?YJTPX 19 March 2009 Spray can for garden use. Periodically it is necessary to have a spray can for use in the garden. I decided to improve on the normal commercial pump up spray cans. Since I have a compressor I decided to modify a 20 pound propane tank, which holds about 20 liters of liquid. The inside of the tank was sprayed with Tremclad paint to inhibit rusting. All the fittings are NPT, National Pipe Thread, fittings readily available in any NA hardware store. The tank is charged to about 3/4 full with a funnel from the top filler plug, with no difficulty. Pressure from an external source is applied to the typical tire inlet valve to a value of about 60 PSI. I found it takes about ten minutes to empty the tank, which is a fairly long time if one is spraying fruit trees in the Spring. The air inlet valve is called a snifter valve, and is the standard valve used to inflate tires, but has an NPT fitting to be installed on tanks. Here is one supplier of the snifter valve. The Spray nozzle is usually sold as a replacement for the typical spray tank. With my design the liquid comes from the bottom of the tank, so there is no necessity for an inside tube. The hole in the bottom of the tank is 7/16 inch and tapped for 1/4 NPT fitting.
I don't know that those tanks have a lining in them? If not they will rust pretty quick and plug your drain hole. I could be wrong but check yours to be sure before you put lot of time into it. Cheers Bob
Little effort is expended in making the assembly. Any tank would do but these propane tanks are readily available. The most pressing use it to spray fruit trees with sulfur and oil. Rust is secondary, usually the spray cans clog from solution residue. I got tired of buying those pump up commercial tanks every year. They are far to complicated with a built in pump and inner dispensing tube. Not one innovator amongst the manufacturers.
