Large volume pumps 8 and 10gpm, gun washing, hose and gun volumes to reduce hand vibration, larger flow, etc

Hello, this is sort of two part topic, not sure if I should have made two topics, I’m new here.
Since using my 8gpm and gun washing fences and decks, my hands are just getting inured, it takes a week to heal after maybe 4-8 hours gun washing a fence or deck. I am presoap, then washing entire thing with shorter lance, old fashioned power washing it, no softwash, that’s what I mean by gun washing? I fixed wrists with velcro stretch wrap brace things, wear thick big leather padded harley winter gloves, nitrile gloves, and my hands feel like severe arthritus, if I knew what that felt like? ya. I also started using #15 and #20 nozzles. I love how fast this thing is compared to my medium machine, but I am almost ready to bag it. I washed 4 gpm for decades, no side effects. I had no idea this would even be a thing, I am bummed by it. I don’t mind arm shoulder back leg workout, but the arthritus type side effects, I can barely use tv remote or pick up stuff.
Soooo, I joined here to ask. I have asked youtube and power washing store, etc.
Here is my theory: so, 3/8 150ft hose, 3/8 whip line. I check pump valves and o rings by the way. All look new and clean. The shop said the vibration could be going up line from pump. Pump seems fine. It just seems like low level vibration from the sheer force of hp and gpm?
The power washing place other place, said ditch my 3/8 whip and 3/8 pump reel and get 1/2 inch whip, 1/2 inch reel fittings, and at least first 50 feet 1/2 inch. Now I want to save this mission, I came this far, willing to spend more if chance I can make this better. I am now also thinking of the 250 dollar 50 gpm guns, it is bigger, and has 1/2 in and 1/2 out, instead of regular guns that have 3/8 in and 1/4 out. I also am going to get 1/2 fittings on hose ends, no 3/8 anywhere, all 1/2 through oversized huge gpm gun. My theory is this will lower the vibration of the 3/8? I think 8 gpm is supposedly good on 3/8, I don’t know what my problem is, if anyone else can relate to this? Oh, one of the youtube I subscribe, he said hydraulic static pressure isn’t affected by using bigger hose, so I don’t know about my theory.
I also have a new general 10.2 pump, and if I make everything 1/2, I would like to put that on. Maybe that will tone down my hp a little ? I like the big volume and lower psi for decks and fences. My buffer tanks plumbed 1 1/2 inch and I have plenty of back water from houses here for the 10.2. Ya, I apologize for any noob stuff long writing trying to explain this. Thanks! -nate

Sounds like you would benefit from a flow-actuated unloader instead of the standard pressure-trapped unloader. Also, get a Suttner 2315 wand. They require much less force to open the trigger and much less force to keep it open so you’ll definitely see an improvement from those two things combined. 8gpm and above is a beast. It’s just the nature of the machine.

Some of the other guys will have to chime in with their suggestions on which flow-actuated unloader. I don’t run one.


Thanks a lot for replying! I have a k7 unloader or something like that. It puts the power on gradually for a couple seconds to ramp up, really like that. I have a gun that is really low pull, it almost clicks into on postion, you can hold it with your pinky. It more feels like I am gripping all this pretty tightly, even though sometimes I remember to try and relax. It kind of seems like a combination of gripping it and the unique vibration of the power, not quite like a sander or multipurpose tool or riding harley or motocross bike. Those things can make hands feels funny, but not just trash them like this machine is, yikes.
Hey, I forgot, one other thing trying, I ordered one of the flat style guns, instead of how they are almost a ninety degree handle?
I also use a cheap angle coupler, at 45 degrees, and spin it all ways around the circle, to always be holding the gun in different ways with different direction forces on my arms and back, helps a lot. But, its the gripping the gun tight and the vibration that I think is the punishment.
Wondering what happens to anyone that goes from 3/8 hoses to 1/2 hoses, if this lowers that vibration of the power. thanks again, nate

Are you sure your K7 is functioning properly? Seems like I remember a bunch of guys complaining about it bypassing when it shouldn’t be and along with that came weird vibrations and some other issues. I don’t remember exactly. You might try to search that on here and see what you come up with.

As far as 1/2" hoses go I can’t help you there. I run an 8gpm too but I don’t notice any real issues with vibration or anything like you’re experiencing. After a long week of washing my wrist may be a little tender but I don’t work on Sundays and I’m always good to go on Monday.

If you don’t have the Suttner 2315 you could always pick one up and see if it’s easier to keep open than your current wand. They’re angled as well so it keeps the wrist in a flatter position and you don’t have to cock your wrist as much to hit gutters and second story stuff.

Thanks, say, that is interesting you mention the unloader. The place I bought the machine, they are great people, anyways, they asked me to send them a vid of the unloader bypass hose hitting hard when I called them other day. They asked about the unloader, I told em…Ever since I got machine, it shot right off the plumbing I had set up to the buffer tank. I had to add a second tank because it agitated so much air into water tank it was putting air into feed line. It was like white water rapids in the tank. Then I added six feet of half inch hose to the 8 feet of 3/8 inch bypass hose, and zip tied two huge steel chrome wrenches to the end of hose in the bottom of second buffer tank because when you let off the gun trigger, the explosive force on the bypass hose was , well, a lot. It would slam the two wrenches around in barrel each time I let off trigger.
I never had a bypass type unloader or ran and 8pgm 24 hp (had an 8 gal 13 hp 1900 psi cat with greens spring unloader, no bypass) before. Anyways, I was like, hey, how do these guys put the bypass into their buffer tank, this is crazy. Maybe the k7 isn’t supposed to do this?

I think this may be ok? Or something similar? I also like that is has 1/2 in and 1/2 out, my k7 is 3/8 out. Not sure the inlet size. Maybe the k7 is the whole problem here>?!!
If I go to 10.2, I would like 1/2 inlet/outlet anyways I think?

I think the pain is just the nature of the game bud, I’ve always complained my arms and hands are sore and so do my guys at the end of the week it’s been like that since the start, not to mention my shot knees from ladders and back and neck pains from being hunched over a bench tig welding 8 hours a day in my previous field. Good quality ergonomic guns do help like the suttner that Texan mentioned. Don’t work yourself to death there is still plenty of life left once the curtains close.

2315 gun. Pressure trap unloader. If a vendor tells you to use 1/2 hose or fittings find another vendor that actually knows what they are talking about. Is your machine mounted on isolaters? It sounds like you are washing decks or whatever with high pressure if I understand your writing. Don’t do that.

Thanks MMH, yes, the years add up huh, didn’t know about stretching or using better form when I was younger, didn’t matter then that much. Now I am always working around the parts of body that got a little worse for wear over the years. I suppose it gives me something to think about washing, the different ways I can be standing or holding gun etc to change up the forces on different worn out parts of body.
I always thought welding would be cool to learn.

Hi Innocentbystander, thanks. I was looking at other unloaders, wondering if the k73 is not working that great or something.
May try the green spring unloader or General Pump ZK1 unloader, prob zk1 for the gradual pressure on effect.
I have a steel skid, with 4 or 6 rubber round bushings under it. I do have a box of those round rubber skid mounting discs. I could put my skid on more wood, that are set on the rubber bushing things, even two or three layers of this, if this would lower vibrations up hose to gun? Is that what you are getting at?
I like the higher gpm nozzles now to lower psi.


I would try the 2315 gun that displaced mentioned and a zk1 unloader. Seems others have had issues with the k7. I wouldn’t get a pressure trapped like ibs mentioned. You’ll hate going from a flow unloader to a pressure trapped. I finally switched over to a flow and love it. They’re so much better than a pressure trapped.

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I second the 2315 gun, its capable up to 12gpm and is different than holding a 90° gun , way easier on my body , Get as many 90° fittings out of your lines as well, lots on here also dont flow water thru their hose reels and just use them for hose storage. Also make sure you always flowing water thru your chem lines when soft wash rinsing because you can draw in air and cause vibration and unwanted cavitation.

Sounds like the ole stud needs to go out to pasture and retire on the good hay and sweet feed. Muscle was a good horse back in his prime… In the 70’s…

I don’t see any mention of a mosmatic swivel before your gun; are you just twisting the hose in the QC? You’re still fighting a lot of torque that way. The swivel will help your wrists a lot


My hands used to feel like they were vibrating well into the next day. Then I quit being a ■■■■■


Thanks Jake, never heard of that, I looked it up, ya, that looks real nice.

Thanks! No chem washing through my power washing equipment,! lol
I was thinking of opening up my whip, reel and fittings its all bottlenecky in there.
Say, the suttner 2016 looks same shape easy pull, more half price because it isn’t ceramic ball made for chem, I wonder if that’s only diff,

Ok, marinegrunt, thanks for help. I am gonna get that zk1 from somewhere, ya, the ramping up power over a couple seconds is pretty nice stuff right there!

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This power washing bigger machines stuff is lots to learn, I thought I knew a lot, lot I don’t know, thanks everyone,