# Gas Powered Backpack Sprayer Setups?



## CH3NO2 (Apr 19, 2017)

I'm looking at alternatives to the Chapin 20V, Earthway S25 etc. I would like to be able to get more spray width from a handheld boom. I would also like to have spray volumes equal to or greater than 1 gallon per 1000 sq ft. (2g or more) for different applications.

Does anybody have experience with builds for something like a Solo 433, regulated down at the wand with a boom / teejet setup?


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## Ware (Jan 28, 2017)

CH3NO2 said:


> I'm looking at alternatives to the Chapin 20V, Earthway S25 etc. I would like to be able to get more spray width from a handheld boom. I would also like to have spray volumes equal to or greater than 1 gallon per 1000 sq ft. (2g or more) for different applications.
> 
> Does anybody have experience with builds for something like a Solo 433, regulated down at the wand with a boom / teejet setup?


I don't think the Solo 433 is a high volume sprayer - it is a high pressure sprayer:



> Output: 0.32 gpm at 145 psi, 0.45 gpm at 290 psi, 0.53 gpm at 435 psi


I think the reason we don't see high volume output from backpack sprayers is because of the tank capacity. Most are in the 4-5 gallon range, so if you had one that was pushing 2gpm it would be very inefficient because you'd have to stop and refill it every couple of minutes.

Have you considered a Gregson-Clark Spreader-Mate or a tow behind sprayer of some sort? To me that seems like the most logical way to deliver the volume you're wanting.

Just out of curiosity, what are you spraying that needs a carrier of 2+ gallons per thousand?


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## CH3NO2 (Apr 19, 2017)

Perhaps then the Maruyama MS75 unit...


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## Ware (Jan 28, 2017)

CH3NO2 said:


> Perhaps then the Maruyama MS75 unit...


Is weight a concern? The Maruyama weighs 21 lbs, plus another 55 lbs with a full chemical tank (6.6 gal @ 8.33 lbs/gal)... that's 76 lbs on your back. I know the Chapin 20V backpack doesn't meet your pump volume requirements, but just for comparison it weighs 10.5 lbs, plus 33.3 lbs with a full (4 gal) chemical tank... or 43.8 lbs total. I would definitely notice another 32 lbs on my back.

I would also have some heartburn with the <3.5 min spray time if utilizing the full 1.9 gpm capacity of the pump in a multi-nozzle application (6.6 gal / 1.9 gpm = 3.47 min). I guess the silver lining in that is it wouldn't weigh 76 lbs for long :lol:. Again, just for the sake of comparison, the 20V Chapin will theoretically run for 10.6 min with a single red TeeJet nozzle at the pump's rated 35 psi. I really feel like this is probably the sweet spot in terms of capacity (weight) and output (gpm) for a backpack sprayer.

Speaking of pressure, it looks like the minimum pressure setting is 90 psi on the Maruyama, which would put you at the very top of most TeeJet performance charts. According to the chart below, you could run 4 blue nozzles or 3 red nozzles without exceeding the 1.9gpm suction capacity of the pump at that pressure, but that would only give you 1.5-2.0 gallons per thousand at a ground speed of 2 mph - you mentioned wanting 2+.

​
All that considered, I still say a push or tow sprayer with a larger pump is your best bet, but I'll be quiet now.


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## CH3NO2 (Apr 19, 2017)

I was thinking of using an additional regulator at the handle to run multiple teejet nozzles on a boom. The Maruyama unit also has recirculation ability.

Will do some further research and post up what I find for additional comment. Just thought there might be someone here who might have been down this road.

I don't mind the extra weight, it is a trade off for less passes across the lawn.

The base case I am working towards is 1g / 1,000. 2.5mph @ 40psi. And then seeing what is possible from there.

I appreciate the angle of a tow behind, but that requires an ATV or some other vehicle that I don't have / need. My yard also has lots of odd curves and pockets so walking is easier for getting full coverage.


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## Ware (Jan 28, 2017)

So at 40 psi, red TeeJet nozzles spaced 20 inches apart and 20 inches off the ground would get you 1.16 gallons per thousand at 2.5 mph. They would flow 0.40 gpm each, so you could run up to 4 with the 1.9 gpm pump.

​
It looks like those gas powered backpacks are north of $700. Call me crazy, but that's not too far from the cost of a Spreader-Mate, which offers a 9 gallon tank, and rolls almost effortlessly in an 80lb broadcast spreader. The boom arms fold back for storage/tight spaces, and you can turn individual nozzles on and off as needed. How big of an area are you working with?


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## Grass Clippins (Apr 30, 2018)

If anyone has questions about the Solo 433, I have one with a watts regulator and teejet wand. Out of the box it's useless unless you're spraying pesticide on fruit trees or something. The minimum PSI is 90 psi, max is 450 psi, the regulator helps me dial it down to 40 psi. Get ready to spend a bit more money to get it ready for lawn care.


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## Greendoc (Mar 24, 2018)

Not his. I have sprayed 1000s of sq ft of lawn with the above items. The boom is fitted with AI 110-04 nozzles. With a regulator right before the trigger, pressure is reduced down to 40 PSI or lower. I cover 1000 sq ft in about a minute. No burning of lawns or killing of trees due to chemical overdoses.


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## Grass Clippins (Apr 30, 2018)

Greendoc said:


> Not his. I have sprayed 1000s of sq ft of lawn with the above items. The boom is fitted with AI 110-04 nozzles. With a regulator right before the trigger, pressure is reduced down to 40 PSI or lower. I cover 1000 sq ft in about a minute. No burning of lawns or killing of trees due to chemical overdoses.


Very nice...what type of regulator is that? I went with a watts regulator attached directly to the pump outlet. I don't have a boom but was considering it. I agree that once you get it set up for lawn their great but getting there is a pain in the A, at least it was for me because couldn't find anyone who had done any mods? I'll share a pic this weekend. I bought mine primarily for spraying glyphosate in the woods. I can get 9000 sq ft on one tank (6 gallons).


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## Grass Clippins (Apr 30, 2018)

Greendoc said:


> Not his. I have sprayed 1000s of sq ft of lawn with the above items. The boom is fitted with AI 110-04 nozzles. With a regulator right before the trigger, pressure is reduced down to 40 PSI or lower. I cover 1000 sq ft in about a minute. No burning of lawns or killing of trees due to chemical overdoses.


What's your starting procedure? We've got the throttle, tank regulator and pressure regulator. I know there's a certain order or process to setting the PSI. Do you set the tank regulator wide open, go full throttle and adjust the pressure at the wand?


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## Greendoc (Mar 24, 2018)

Grass Clippins said:


> Greendoc said:
> 
> 
> > Not his. I have sprayed 1000s of sq ft of lawn with the above items. The boom is fitted with AI 110-04 nozzles. With a regulator right before the trigger, pressure is reduced down to 40 PSI or lower. I cover 1000 sq ft in about a minute. No burning of lawns or killing of trees due to chemical overdoses.
> ...


I set for 0 pressure, start, increase throttle, increase pressure on the tank regulator, make final adjustments at my regulator. Depending on what I am doing, pressure can be 25-100 PSI. The regulator depicted is a small, non relieving regulator. That picture was taken back in 2008. Since then, that regulator changed to a Watts 263A. Heavy, but at least I can get overhaul parts for it.


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