Building A Boom Sprayer With A Foam Marker

After borrowing a boom sprayer powered by an electric pump I was just not impressed with the pressure that the electric pump was capable of maintaining. After a bit of research we decided to make a boom sprayer for the New Holland TC-40D powered by a Hypro PTO driven pump. And since it was always near impossible to know where we had already sprayed with the borrowed sprayers we decided to construct a foam marker for the new boom sprayer.

The foam marker is independent from the boom sprayer. That is it can be added to just about any sprayer that you may already own. The foam generator is very simple to build compared to the boom sprayer itself. A good foam marker can be constructed for as little as a hundred bucks, not quite sure why they cost $800. to $1500. commercially.

I acquired a compact 12 VDC aquarium air compressor that is capable of a continuous air supply. It will be mounted in a Tupperware box along with two miniature 12 VDC solenoid air valves.

One solenoid will control air to the left foam generator and vice versa. Each flexible air line will run to a foam generator fashioned from a 5 gallon fuel Jerry Can, containing an air stone & the same foam concentrate used in AG booms. The stuff is readily available at 29 bucks a gallon and it is mixed with water somewhere around 160:1 so it goes a long way. It makes foam in the consistency of shaving cream. The output from each generator will run to a small tube at the end of each boom where it will dump on the grass. The foam concentrate was purchased from Agri-Supply.

The air compressor will be powered through a DPDT switch. In one position the compressor will run constantly to initially prime the system. In the other position a small onboard solid state timer will cycle the air compressor automatically. There will be two pots on the board, one to control the on time (pulse), the other to control the time between on cycles (pause), so it should be easy to adjust according to our ground speed.

There will be a SPDT switch that will control each of the two air solenoids so that foam can be dumped from either the left or right boom as needed.

I like to recycle wherever possible. It's good for the environment and in most cases saves some money too. The first picture is of an old section of rusty fence gate that my next door neighbor donated to me. It was constructed of 1" X 1" X 1/8" steel tube, which was perfect material to make the folding boom out of. I really like recycling, especially when it saves me $$$$.

Click on any thumbnail for a full size picture.
This is how the boom starts out, from a section of old rusty gate.

And I needed to fabricate 4 hinges from angle iron so the boom could collapse
when it strikes an immovable object or for storage purposes

This picture shows both boom end sections.
One section is still rusty while the other section has had all the rust and
paint removed using a simple process of electrolysis.

Here's the setup that we use to remove rust & paint via electrolysis. To learn more about
this process click here. Note: We keep this outside because of the
hydrogen gas which is created in the process. Watch your cigarettes!

The battery charger is kept dry inside the pole barn and Romex wire runs out to the bath.

The platform that was used for the boom sprayer was a Carry All
We used treated 2 X 12s for the base and back-drop and attached them using carriage bolts.

Close-up of hinge & return spring in fully collapsed position.
You'll need to have some slack in the hose to the nozzles
to allow for the boom to collapse without damaging the hose.

Chains were added to both ends of the boom. Lowering the boom so the chains
just touch the ground sets the nozzles at the correct working height. The fitting on
the very end of the boom is where the foam will eventually exit. In our case the nozzles
are on 20" centers so the foam needs to leave the boom 10" beyond the last nozzle
or the nozzle spray will hit and dissolve the foam.

I stopped by a local hobby shop and picked up two packages
of Du-Bro fuel can cap fittings.

I used two standard 5 gallon poly fuel cans and drilled a hole in each
jug being careful to place the hole pretty close to the spout so the
fitting could easily be placed in the jug using a pair of needle nose pliers.

Add an aquarium air-stone purchased from Wal-Mart and weighted with
a couple of stainless steel bolts to keep it in the bottom of the jug.

Tuck the completed assembly down in the jug. At this point if you fill the jug with water
to within a couple of inches from the top and add just a bit of foam concentrate, then add
just a couple of psi air pressure to the aquarium tubing the jug will produce great gobs of
foam with the consistency of shaving crème. All you need now is a reliable air source.

We purchased a new Boyu 12 VDC aquarium compressor from eBay for $45.00
It is rated for continuous operation and should suit our needs.

We purchased a solid state Mark-III timer from www.allelectronics.com for $9.95
The timer is adjustable for the pause & pulse cycles and will be used to cycle the compressor.
I made a couple of minor modifications, adding a heftier relay to handle the compressor, two 250K pots,
and two 220 microfarad. electrolytic capacitors to increase the cycle rate to 2-60 seconds respectively.

Keep in mind that a timer is an option. The foam marker can just as easily be controlled with a simple
on/off switch or foot switch if you so desire to keep it simple.

We purchased two miniature 12 VDC air solenoids from Surplus Center. The solenoids
will be used to switch the air supply from the left or right side foam tank.

The compressor, solid state timer, relay, and solenoids are all housed in a
Tupperware container to keep them dry and tidy.

This is how we laid the components out on the Carry-All. We used a 65 gallon poly
tank for the chemical

Since the compressor is mounted lower than the Jerry Cans an aquarium check
valve should be used on each Jerry Can to prevent soap solution from siphoning back to the
compressor in the off cycle

This is the cap that we remove to drain our 65 gallon tank. The strainer assembly
is just to the left of the drain.

Looking in the opening of the tank you can see the agitator assembly that keeps the
chemicals mixed with the water.

Here you can see the watering type wand (high volume, low pressure)
& the slack that is needed in the hose to enable to boom to be collapsed

Here you can see the RV plug that used to make the electrical connection
to the tractor. You can also easily see the 5" casters that were installed.

We used cam & groove fitting to connect the Hypro pump to the suction & discharge
hoses. We also used propriety fittings so that the two lines couldn't be
accidentally connected incorrectly.

Close-up of parked pump showing cam & groove plug & cap. These types of pumps
are prone to internal corrosion when they are not in use, however if a 50/50 mix of water
and anti freeze is added to the pump before the blank-off cap and plug is installed before storage
this problem is eliminated since it seals out air. Air is necessary for the corrosion to take place.

Once the boom sprayer is disconnected from the tractor the suction & discharge
lines can be coupled together keeping debris out.

This is the manifold that we put together. 1=pressure relief bypass 2=return to tank 3=pump outlet
4=boom 5= gun sprayer 6=adjustable pressure regulator to dial in
the required sprayer pressure 7= glycerin dampened pressure gauge.

I added a wind up reel that holds 100' of hose for the wand and a length of PVC to park the wand in
when not in use so it's not flopping around on the platform.

Close-up of the reel equipped with ball valve & quick coupler to make attachment of
wand or gun quick and leak free

I wanted to eliminate drilling holes and keep the tractor looking as original as possible.
3 conductor wire that was pulled to the right fender control area. This wire was connected to a
two position Carling waterproof SPDT switch that controls the foam output between the
left and right side of the boom.

Wires pulled (7 conductor from sprayer & 3 conductor from left/right fender) to a point under the
instrument cluster where it was all fused, connected, and insulated properly.

We mounted the switch to control the spray rig. 1st position is off, second position is automatic
timed operation of air compressor and 3rd position is manual run or purge for initial startup.

New waterproof SPDT Carling switch that controls the foam to the left/right side of the boom.
I never used the original rabbit/turtle switch that was mounted here since there is another on the joystick
itself, so I installed the new switch then pulled the paddle handle off the original switch and installed it on
the new switch. It looks stock and the paddle is much easier to find with my finger when I need to
reverse the foam output.

RV plug/receptacle that I used. When the sprayer is no longer connected I tuck the receptacle behind the seat.

We sprayed a section of concrete to show the even spray pattern that the boom puts down.

Close-up showing a foam ball almost ready to drop

We started doing a bit of experimenting
and used the end of a plastic watering can covered with a ladies hose on the end of the boom.
It puts down grapefruit sized balls of foam that stick to the grass and are very easy
to see from a distance.

This is what it looks like spraying and laying down foam at the same time.
It really works slick!

Here you can see that it's very easy using the gun sprayer from the tractor seat.
although with the 100 foot of hose on the reel you could use it in the garden just as easy.

I ran roughly 150 gallons of water through the sprayer to test it and in that time used a total of only
2 gallons of diluted foam solution, so the foam concentrate should go a long, long way.

The features of this boom sprayer include:

~ 10-foot collapsible boom with a full 12-foot spray pattern
~ Two boom height chains (one on each tip) to easily set proper boom height to achieve proper spray pattern
~ Boom utilizes seven TeeJet brand spray bodies with diaphragm check valves for drip-free shut-off,
XR-80 degree nozzles, and nozzle strainers
~ Both boom tips are equipped for foam marking
~ Foam generators utilize a commercial 12 VDC diaphragm air compressor rated for continuous operation
~ Air compressor can be switched from manual to timed operation with the flip of a switch at the instrument panel
~ Foam can be directed to either boom tip with the flip of a switch on control cluster (right fender)
~ Solid-state timer is fully adjustable on both the pulse (on time) and pause of air compressor cycle
~ Hypro brand 6 roller PTO pump protected by an in-line 80-mesh strainer and equipped with proprietary
cam lock couplers to prevent incorrect inlet/outlet hose connections.
~ Parked Hypro pump has a set of cam & groove caps to seal pump when not in use and protect it from corrosion
~ 65-gallon poly tank with easy-to-see gallon markings to assist with the ratio of water/chemical mix and also
equipped with internal agitator to keep chemicals thoroughly mixed
~ Twin ball valves to isolate poly tank
~ Spray manifold equipped with adjustable pressure regulator, glycerin dampened pressure gauge, and ball valves
to isolate boom or wand
~ Trigger spray gun with adjustable spray tip & quick attach coupling
~ Watering type wand (high volume, low pressure) with quick attach coupling
~ Hand reel with 100 foot of EPDM hose equipped with ball valve on quick coupler to make attachment of wand or
gun quick and leak free
~ Two separate 5-gallon foam generator tanks. Each controls one side of the boom for hours of use between refills
~ Parking hangers for both wands, the PTO pump, and the flexible intake/return lines
~ Electrical connection is made from sprayer to tractor via a 7-pole trailer plug & receptacle for quick hook-up
~ 5-inch castor's for easy moving of sprayer within the pole barn