What i really want to know is how @dcbrock is getting 8gpm @3000 psi with a gx630. I’m all ears.
I know, right?
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Well, think of it this way. The 690 is exactly the same as the 630 just with a ‘better’ carburetor that gives it 22.1hp. My 630 is rated at 20.8hp so yeah, it’s gonna Power an 8/3000 just fine.
I did a bucket test and psi gauge to verify it.
My understanding is that you need 22hp for 8@3000 based off of 8x3000 divided by 1100, you have 2 hp less and 200 feet of hose getting 3000 psi, what am I missing here 
If I’m having issues with stripes, wouldn’t going in a circular pattern just create circular stripes? You’re still over lapping correct? I’ve read and watched videos on the “circle technique” but don’t see how it wouldn’t cause the same issues but just in a circular pattern vs. a vertical pattern. Can you elaborate more?
Striping and etching are 2 different things, one you fix by post treating the other you fix with your wallet. Any technique on crappy or fresh concrete will etch it, it doesn’t matter witch way your dancing.
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Well, with a two nozzle you’ll have a clean stripe and the middle doesn’t get as much ‘love’ so you get those tiger stripes.
The push pull method seems to eliminate the issue, thankfully.
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Im curious why 4 bar surface cleaners especially the smaller ones 16, 19s the nozzles arent spread out more to where they could cover almost the entire cleaner instead of just making the outside area larger
I’ve always wondered that myself. Got to call WW on Monday anyway, I’ll ask
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They wouldn’t spin as fast, you would get less cleaning per inch of forward movement. Same issue arises when using an oversized surface cleaner on an undersized machine. If you travel forward with your surface cleaner the top and bottom edge of the skirt will do the cleaning, if you move side ways with the cleaner your left and right edge will be doing the cleaning, as you can see what ever way you move you will be open to striping, it’s just the nature of a straight bar spinning in a circle. a 1 bar 4 nozzle surface cleaner just widens the cleaning diameter on the outside of your skirt giving you less of an obvious line. And yes they do clean better than a 2 nozzle, provided you have it matched to your machine, a wider pressure point will clean more in less time for the same distance of travel.
What he’s saying though, what would it do if you moved inner nozzle in say another inch. There’s a boatload of overlap in the spray the way they have now. With right angle on it, not going to materially effect speed of bar.
I hear ya. You’d think so. I thought it might. But it doesn’t.
Yes, definitely overlapping quite a bit.
Give it a try. I think you’ll see it works.
It won’t render it useless, it will still work, you just won’t get as much spin not earth shattering difference but you will notice it. The best way I can describe it is to grab a fidget spinner and blow compressed air on the outter edge and and work your way in to the bearing and see what happens, it’s the same principle with a surface cleaner.
You’re still getting thrust from the outer though, I agree that’s where a lot of the speed is coming from, just not sure how much it would affect moving inner in a little more. But you may be right. I do know that if I could invent a spray bar that cleaned well and could advertise a no streak bar you and I could both retire in about a year.
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I feel like it’s possible with a very large machine 14+gpm on a 19 in getting 25025 tips on a 6 bar would almost cover the whole thing but at that point also running a bigger surface cleaner would be way more efficient
Your correct, but now flow is getting divided by 4 nozzles. 2 where you want them for spin and 2 where you don’t want them for spin. 
I’ve spent many nights pondering on ways of retiring racer, true story lol.
Hey, my 4gpm with a 2 nozzle cleans as well as my 8 with 4 nozzle so not all that covinced the 4 nozzle all that much better. Best cleaning machine I’ve ever had, had a 3 prong mosmatic bar on it. never left stripes.
Hold on to that thing! Because that’s not the experience for a lot of us.
What kind is it?
My ultimate would be a carbon fibre 4 bar 4 nozzle 
. But no one puts that amount of engineering into a surface cleaner 
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It’s been gone. It was an old 32" Northern tool machine that had wheels and a rubber skirt that was a real pain, that a friend of mine had that he sold me for $200. He had put the swivel with 3 bar on it, think it comes with one anyway. But it cleaned nice.
Was a much older version of this. This one has 4 nozzles but spaced out so that may be reason they don’t stripe as much
https://www.northerntool.com/shop/tools/product_200660784_200660784
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