Building boom sprayer w/foam marker

[Acilia]

I just figured out how to make a foam marker system under $30: I used a large 4" aquarium bubble stone powered by an 12V air mattress inflator. I then filled an old hospital IV bag with foam solution and hung it from the tractor's roll bar. The trick was to use the IV needle to inject the solution into the air hose just before the air stone so the air pressure pushes the solution through the stone and makes copious amounts of foam on its way out. I was going to put the stone in a container to hold and shape the foam but found out that it was not necessary so I just tied the stone to the boom keeping it vertical so the air and the fluid flows from the top down. I found out (the hard way) that you must wrap the IV bag to the roll bag with duct tape, or the whole thing will go flying away at the first hard bump!

I purchased the 12V inflator ($8), some air hose and the 4" air stone($2) at Walmart. The IV bag was left over after giving my cat some fluids. I use commercial foam fluid because it lasts longer but dish soap might work too.

After adjusting the fluid rate, I get a 1" foam blob every 10'-15'. Very easy to see even on a field of 1' high vegetation.

 

[texasjohn]

Cool first post...and innovative...I may try this also...seems less complex than some other methods I have tried...and I have all the parts already.

 

[Acilia]

Thanks, I tried to make the foam marker with the bubbling tank approach as described in the earliest posts but found out that the long tube (from the tank to the tip of the boom) really slows down the flow of the foam. I used the cheapest large tube that I could find, a vacuum extension, but I think the corrugations on the tube increase the laminar friction too much. I was getting one blob every minute or more.
I then setup to make the foam at the tip of the boom, I tried several approaches using a 3D printer to make the custom parts. After many tries I discovered that injecting the solution into the air supply uses the force of the air pressure to move the solution through the stone, which does not do if the fluid is simply dropped on top. The size of the bubbles is proportional to the air pressure and the mix ratio, too much air makes the foam bubbles too large. Too much fluid keeps the foam from forming properly and makes it runny.
The IV tubbing is very flimsy, I don't expect it to last more than a couple of weeks. I'll be looking for other ways to hold and supply the liquid. I will also look into using a more conventional 'T' coupler to inject the fluid but worry that I'll have trouble adjusting the flow. Takes very little solution to make the foam and the flow needs to have a fairly fine adjustment. There is not a lot of difference between too little and too much.

Let us know how it works for you, and if you come up with a better way to supply the liquid.

 

[forester2]

I finally built one of these to the original specs except I used a portable air tank for the air supply (already had one). Get about 50gals of spray using a 7 nozzle boom. Foam marker concentrate is well worth the $. Refill air tank with a cheap Harbour Freight 12v compressor. Would love a continuous air supply if I can find something affordable and easily availible.

 

[sixdogs]

PineRidge--I know this is an old thread but that is really a good build on the sprayer with some good ideas.

 

[PineRidge]

Well it’s been more than a couple of years since I made this sprayer, I sold it years ago and I’m about to dive into making another so here we go again hang on.

My plan a few mowing seasons back was to be able to pull a liquid fertilizer sprayer behind my Z655 John Deere Zero Turn mower. I purchased I believe a Fimco 27 gallon unit from Tractor supply. I use a rocking piston pump to aerate a pond on my property so when I needed to use a foam marker I had the rocking piston pump on the back of the Deere.

Since the pump was 115 volts it was necessary to use a 12 volt inverter to bring up the voltage to run the pump. The pump pressurized a plastic carboy that was filled 3/4 full of water with a couple of ounces of the foam concentrate sold online. Also in said carboy was a large air-stone that generated loads of foam

I had the foam pumped to the simple PVC pipe boom that I constructed and all was well for 2 mowing seasons. I have recently purchased another John Deere Z740R zero turn that will be arriving next week. So I need to construct yet another foam marker (continued)

 

[PineRidge]

The new plan:
I really don’t want to put anything on the new mower other than myself that is. Since the sprayer that I now own is on wheels it’s very easy to connect to a zero turn filled with 25-gallons of fertilizer. I’m thinking of mounting everything on the sprayer itself. For the few times I’ll actually need it I want to pull the dry spreader for grass seed I’ll need to connect the grass spreader to the rear of the liquid sprayer. Am I talking convoy here, breaker, breaker?

And I want to get away from that 115 volt thing so I’m going to opt out of the rocking piston pump and the inverter for safety reasons around liquids.

I have a 12 volt large volume air pump ordered from Amazon that I’ll be trying. This time around I’m thinking about feeding the foam exiting the liquid tank to a foam generator that some used to make air-crete with should be a denser foam and add the the cling-time on the grass. I’m going to make the generator out of a short length of 2” PVC pipe.

At this point in time if anyone has any suggestions post them here as I’m open to all ideas.

BTW I still have a clean Z655 sitting around I’m needing to get rid of.

 

[PineRidge]

I ended up using a 5-gallon plastic carboy. Purchased a 12 volt aquarium air pump and connected a large air stone to it and dropped it in the carboy. When the pump is activated it generates foam that is then pumped through a short length of 2” PVC pipe that is stuffed with stainless steel wool. The resulting shaving cream consistency foam is then piped to the ends of my spray boom. It’s pretty simple and works really well.

BTW The Z655 has been sold and was replaced with a Z740R. Wish it would quit snowing so I can try it.

 

[koshari]

just set up a povvo marker basically using a cheap 12v automotive compressor,

then i used a 20l plastic drum with a barbed through hose into the lower outlet and put a 1" barbed outlet in the lid on the top for the foam to come out. the air hose has a shroeder valve on and to attach to compressor hose and act as a non return so no water gets back to compressor, simple but works fine.