MARQUIS, Sask. Ñ Darren Thul performs as many as five spray passes a year on the 11,000 acres he farms nears Marquis, including burnoff, in-crop, fungicide, insects, desiccation and fall Roundup. All this spraying puts up to 50,000 acres a year on his sprayers.
Thul said the biggest complaints farmers have about sprayers is they’re underpowered and hydraulically driven.
“When something goes wrong, it’s very expensive. We wanted to get away from those ($5,000) and $10,000 repair bills,” he said.
“We solve the horsepower issue by using highway tractors. They last for years and the ones we build are generally around 400 hp. Being direct drive, you don’t lose the 30 percent power due to pumping oil.”
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He said pumping oil is an inefficient way of moving anything.
“What we gain by this is our trucks hardly work at all. We’ve got full power and direct drive, so minimal maintenance is needed on these trucks. They should last anyone’s lifetime plus their kid’s lifetime.”
If problems do occur, such as a blown seal on the axle, a rear end or transmission, they’re less expensive to repair than a hydraulic drive motor on a hydraulic sprayer.
“And if the engine should happen to give you trouble, it’s the same cost as any engine.”
Thul has used mostly farm-built units for the last 10 years. Recently, he used a semi with conventional tires and no extra clearance. He removed the duals at the back, put the rims back on and ran single tires.
“We found in wet conditions we were having too much compaction and not enough clearance. We also found that any time you had moisture, you were done. With the highway tractor tires, you couldn’t get out of any type of moisture.”
While the trucks could handle hauling 1,200 gallons, fields were being damaged.
As the sprayer evolved, Thul started looking at different tire sizes. In the stock configuration, he couldn’t use large tires without them rubbing each other or the truck.
“I wanted more clearance and I found the biggest tires we could find Ð 81 inches (206 centimetres) tall. We decided to cut the frame and make a prototype. It worked excellent, so we knew we were going to be in business.”
Thul uses 380/90R54 tires, which gives him 79 cm of clearance under the frame. He builds the rims, hubs and lift setup for the front in his shop on the farm.
“The big tires raise the frame on the back end. On the front, we take off all the original stuff. We use the same axle, but there’s no spindle, brake parts or anything from the original. The front end is rebuilt, lifted and put back together.”
The steering has to be strengthened because the front end is wider.
“If you hit a trench in the field, you don’t want your tires to flop out on you. We have to make sure we build it beefy enough.”
Re-engineering the front end is tricky. Thul tried three setups, trying to figure out how to get more clearance. He eventually discovered that Dave Bryant in nearby Central Butte, Sask., had a patent pending on making highway tractors into spray units and had figured out how to get the lift he needed.
“We became partners and that was the start of Spray Monster.”
Because the front end was widened, the rear wheels also had to be extended. When Thul builds the rear rims, he adds a 30 cm extension from the hub to the inside of the back wheels. He also cuts the front fenders to make room for the large front wheels to turn.
For the suspension, he looks at every truck individually.
“We see if we have to put in any different air valves to stop flow from side to side, so you don’t get too much sway. Whatever it takes to build these things to be good enough to be in the field so they last is what we’re going to do.”
Thul has built single drive axle four-wheel sprayers and tandem drive axle six-wheel sprayers.
With the tandem axle units, he has to cut the frame between the two axles and add a 60 cm to one metre extension in the frame. The change in frame length depends on the original distance between the tires.
“Every time we do an original truck, it takes a lot longer to do the first one than it does the second. At this time, we’re going with a Marflex sprayer we purchase out of the States. We’re using a 1,300 US gallon tank on the four-wheeled unit and a 2,000 to 2,200 gallon tank on the six-wheeled unit. Boom lengths depend on whatever the individual wants. Everyone’s skill level is different.
“If your land is perfectly flat, with no ditches, you might go to a 120- to 140-foot boom. But if you spray under normal conditions, with hills, trenches in the field or things like that, you’ll probably go from 80 to 100 feet. My sprayers are 100 feet and they’re a nice match.”
A spray controller system comes with the Marflex sprayer and includes a push-button handset in the cab. Thul said producers can fold out one boom halfway and fold out the other half, lift up one boom or put one or both sides out.
To run the hydraulics and spray pump, the Marflex system includes a 20 hp Honda engine mounted on the back of the truck.
“It’s a self-contained unit that drives the hydraulic motor and water pump by belt. It doesn’t need anything from the truck. If someone isn’t happy with the gas engine, we can put a small diesel engine at the back, which is more expensive, or a hydraulic drive kit under the hood of the truck, off the motor. But that’s a fair bit more money, too. All the truck does is carry the unit.”
With the auto rate controller, Thul said the sprayer can operate from 10 to 50 km-h and speed is easy to maintain. For example, he sprays at 30 km-h, but if somebody wants to go faster, it has lots of horsepower to do it.
“The faster you go, the quicker you have to be on controls.”
Thul said fuel consumption for the sprayer works out to about 10 cents an acre.
“That’s what I used to think was a fair amount to spend on foam when we were using foam markers.”
Because Spray Monsters have so much power and traction, Thul said he can maintain 19 km-h going through water and mud. However, if he gets stuck, he needs something to help him get out.
“We wrap a cable around either one or both rear ends and make it so all you have to do is hook a cable to the back or front and pull it out, without damaging the unit. If the axles come, you know everything on top has no extra pressure on it. If you sink this thing and you want to pull it out full, you better pull from the axles.”
Thul said by starting with used highway tractors that are still in good condition, he expects the Spray Monsters to last a long time.
“These engines are never working. These trucks go millions of kilometres. The ones I’m building right now have four hundred and some thousand km on. You can imagine how many acres you can do with another 400,000 km. And that’s still really low mileage for these trucks.
“If you run a truck on the highway for 12 hours a day for one year, or you run it five times across a 5,000 acre farm, it takes 26 years to do one year’s highway use. And if in 10 or 20 years time you have problems with that truck, there’s thousands of them at wreckers, so you’ll never have problems getting parts. On most farms, somebody can fix everything on these units.”
Thul has used four highway tractor models when building sprayers and said there are certain trucks he can’t use. He has to look at the truck before he builds.
“I want to buy something that has a lot of life left in it and is in very good shape. A person is going to have this for the rest of their farming. They should never wear it out.”
The final cost of the Spray Monster depends on the truck he uses. The ones he’s building right now are 2000 Volvos with a little more than 400,000 km. He said the four-wheeled units will cost around $120,000.
“I’m going to stick with nicer trucks, so typically they’ll be between $110,000 and $130,000. If these things cost $120,000, you run it for five years and it’s down to $70,000 or $80,000, why would it ever go lower than that? The drive train was used to start with, so it was already depreciated.”
For safety reasons, Thul unhooks the top end of the transmission to limit speed between 55 and 65 km-h.
“I don’t want anything to go faster than that. If your kid gets out there, he’s going to go 60 mph (100 km-h). The tires are only rated for 30 mph (50 km-h), so if you go faster than that, you’re going to start looking at problems.”
Thul said the sprayer has lots of pulling power because it is built on a chassis originally designed to pull heavy loads. If producers want to hook a trailer up behind it and tow water with them, they can hook up the air line from the semi and keep it legal, with lots of braking power.
“That’s the ideal thing. I wouldn’t hesitate putting thousands of gallons behind it, with the proper trailer. Then you’re self-contained. You don’t need somebody dropping water off in the field. You turn it into a one-man show.”
Thul is building and selling the Spray Monsters from his farm, but as more go into the field, he may move to a dealer network.
