Intermediate Question How many SF of Concrete per hour?

[Camelot]

Hey guys and gals...I'm adding an 8gpm machine to my repertoire (woohoo!)...At the risk of opening up a can of worms, how much concrete can be done (roughly) per hour? I am not interested in drive time, setup, breakdown, etc. I'm talking about from the time I start walkin' with my 30" vacuum surface cleaner...At 8gpm, how much concrete can I expect to clean in an hour (assuming everything goes the way it should and I'm on a competely flat piece of concrete)?

I'm trying to get a feel for what to expect with an 8gpm machine (yes it's hot water)...thanks for any help!

- John

[MMI Enterprises]

John,

Answer can't really be based on the gpm of the machine but rather the diameter, setup efficiency of the surfacer, and how much cleanliness is willing to be foregone. The rinsing will of course be subject to the gpm of the machine but you've kind of limited the discussion with just surfacer use.
I can and have on occasion talked all day about how a sufacer is not actually near as limited to machine size as some would have us believe. As I always say it comes down to time on contact and adjustment/sizing of the tips. See the bars all spin plenty fast enough whether it on a 4,5,8,10, etc. sized machine. Now don't confuse what I saying here folks as of course an 8 will always produce more cleaning units compared to a 5 so it of course is capable of cleaning better on the given area. What comes to play though is that ya still have to move the machinery over the area no matter what it is hooked to.

But to sort of answer your question, I suspect you could do anywhere from 3k to 8k an hour with a 30" machine. Straight up walking with just minimal overlap can see well over 10k per hour on other types of swathy machinery.
For instance, fast walking a 24" machine of another type(floor scrubbers) I can do 10k in 45 min... is about same time on same area if normal walking a 32". These are different type machines but walking is walking..Manufactures on other hand tend to claim much better footages in their specs and are just based on math rather than real world situations.
Now getting back to pressure machinery, an 8 cleans better so in theory if bar is speedy enough and your willing to sacrafice some of its extra cleaning power by walking faster than say a 5 gpm it should in theory gain you more sq footage getting done but at a 5gpm level of cleanliness.(if it does not stripe the slab that is from walking too fast). So again, my best guestimate for an 8 being run real fast could see you doing 8k per hour since I know I can do somewhere around 5k with a 5gpm with 5gpm results. Actually though when it comes down to it.. these machines (well mine at least) do not put out to spec since the pumps get wear on them and there are restrictions of water traveling through hosing and such. I get no where near 5gpm at my tip but I still push big diameter surfacer just fine.
Very interesting topic!

[A and J POWERWASHING]

good anwser kevin

[tools000]

it will do a little under or about 8000 feet pre hour

[tools000]

that is if it is a hot unit

[David O'Connell Jr.]

A LOT depends on the surface.
We spent ALL DAY cleaning 40,000 sqft. (2 people, 2 8 gpm 2- 30" 8-9 hours of run time)
IT'S the rinse that kills you.

There is NO cream left on 99% of the 800,000 sqft we are cleaning, Its like cleaning a road (which it actually is)
The concrete is 25 years old.

[Camelot]

I understand all the pitfalls...I'm not new to cleaning concrete...I'm new to an 8gpm machine. Again, please assume the surface is flat, and the concrete is mildly dirty...just trying to get a ROUGH idea of what to expect in terms of square footage. I know there are a billion snags you can run in to like rinsing, uneven surfaces, gum, stains, prep, etc. Maybe a better way to phrase the question would be: All things being equal, how much more concrete will an 8gpm machine clean as compared to the same surface being cleaned by a 4gpm machine? Thanks for the responses...I appreciate it.

[tools000]

good job reef

[MMI Enterprises]

John, Would be easy to say it do no more and no less area if using same surfacer and not figuring in rinsing or complications. OR that it do twice the area if all were equal in way of expected results and but surfacer is larger. There is no way to figure a way around the rinsing or the compications though. Look at David's results.. he is at 2k to 2.5k only even with the big machines. Rinsing and moving hosing, etc. takes toll that just can't be figured accurately.
Best way I can figure to gain speed with larger setup would be an attempt to tweak both the rinsing and surfacing acts by increasing surfacer size and then configuring a half moon type shroud to it that forces the escaping water and debri to blow one direction only towards where you will be cleaning in an attempt to auto rinse or at least lesson the rinse process.

All things being equal, how much more concrete will an 8gpm machine clean as compared to the same surface being cleaned by a 4gpm machine?

None..if the surfacer is tuned and spinning sufficiently the same with the 4 compared to the 8. Reason being that the surfacer swath is the same and the operator will still be moving at a speed that is comfortable or normal. That speed so happens to be slow enough that a 4 or 5 gpm machine can keep up. In theory you could run faster with the 8 if the surfacer is underrated for what it's units could be pushing. Btw, my hydrotek bar/swivel does not get me same bar spin as my diy bar that was utilizing a deublin swivel.

[big mike]

One item that seemed to be missed here, is that he mentions a 30" vacuum surface cleaner. I can run my Big Guy way faster than my Mosmatic vacuum unit. The suction slows you down, as does the limited length of vacuum hose. Your money ahead if you're doing a large area (such as a ramp) if you set up your recovery equipment at the drain, rather than trying to vacuum it up with a surface cleaner. We only use the vacuum surfacer for smaller areas, and in poor drainage areas.