Water Cannon as a Herbicide Sprayer?

[garybdavis]

I purchased several used water cannons to keep my portable welding under control. I bought four of them off ebay for about $10 each including shipping. These are the rechargable stainless water fire extinguishers that are pressurized with air.

Anyway, I've got a couple extra ones and was thinking about converting one of them to a herbicide sprayer. I plan to take the standard hose off and replace it with a slightly longer one with an adjustable spray tank nozzle on the end. Anyone ever done this? Any issues to watch for? Surely I'm not the first one to think of it.

[J hall]

Surely I'm not the first one to think of it.

Maybe you are.
It would work I guess, but I think a hand sprayer would be more convenient.

[hankj]

As long as the hydro dates are current, you can pump any low viscocity liquid from one.

I've seen a DIY type guy at a service station that had a 175 psi air system blow one up trying to pressurize it. They are usually rated for 150 psi max pressure.

It was not pretty.

Hank

[J hall]

I've seen a DIY type guy at a service station that had a 175 psi air system blow one up trying to pressurize it. They are usually rated for 150 psi max pressure.

It was not pretty.

Hank

I hope he didn't hold it between his knees to steady it

[hankj]

Actually, the service station was right across the street from the firehouse.

We heard the boom, looked out the bay doors, and saw people milling arond this poor idiot, so we jumped on the Squad and responded. He was lucky. The seam opened up on the side that was facing him. The can headed away from him, then hit the concrete island and bounced up and caught him in the chin.

Broke his jaw, but other than a liquid diet for a few weeks, he probably healed OK.

Hank

[Sandy]

Depends a whole bunch what the insides are made of. Almost all weed, bug and fertilizer sprays can be pretty caustic. If you notice they are all made from plastic, brass and stainless bodies and parts.

[hankj]

If Gary has what I think he has, it is a pressurized water fire extinguisher, which was very common until the early '70s.

Several over-pressure accidents that resulted in catastrophic failures pretty much put an end to the use of those, but I still have two, and properly cared for and charged, they are great class A firefighting tools!

Hank

[VinnieNC]

My dad and I have been using ones like this for years. We both have the 'wide mouth" tanks that have a 2 - 3 inch opening on top, some models have a much smaller 3/4 to 1 inch hole. The wide mouth makes it easy to fill and not spill the chemicals. We fill them up to the line and screw on the top snug, hand tight. Pressurize with the compressor until the gauge is in the green. I think this corresponds to around 100 psi.

To attach the sprayer wand and hose, you can peel apart the metal band that crimps the hose to the barbed fitting in the head. Once you have removed the hose, you can put your own braided high pressure chemical resistant hose on. Mine is about 4 feet long. Of course wand is on the other end of the hose.

The stainless steel tank will stand up to most herbicides and garden chemicals, but the plastic and rubber parts in the head will suffer and cause leaks if you don't rinse it out after each use.

Usually, when the chemical is exhausted, there is still a little air in the tank. It will spray about 15 - 20 feet depending on the nozzle.

One tip when pressurizing: When you put the air chuck to the schrader valve to pressurize the tank, hold it down until the needle is in the green and don't let up (on-off-on-off.) The reason is that once you get some pressure in the tank, as you lift the chuck off the valve, some chemical will escape out of the valve and squirt you. I usually get the compressor pumped up completely, and pressurize the sprayer in one shot.

Hope this helps.

-Vinnie

[garybdavis]

Ah, I knew I wasn't the only one who thought of this. I plan on using it for roundup and remedy for spot treatments here and there around the shop and fence. I'm guessing if I rinse it out good after each use, it shouldn't be a problem.

Thanks!

[jake]

if ya replace the seals with buna n or nitrile you will be in pretty good shape glycophosate is very hard on non compatible plastics and remedy is realy hard on metals same thing dont leave it in there i had a buddy leave 2-4-d in a stainless spray tank and it was leakin at the weld seams after 2 weeks of it in there.

i took one of my hand tank sprayers and put a truck rim valve stem in it and i shoot 40psi in it and it works wonderfully