Surface Cleaner for red exposed aggregate concrete drive/paths

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alisam

830 posts

Ultimate Geek

#293011 21-Dec-2021 07:23

For the last 25 years I have cleaned the drive and paths laid all around the house with a pressure washer (water blaster).

Neighbours say I should use Wet and Forget or 30 seconds, otherwise I would damage the concrete. But after 25 years, I don't think it has had a detrimental effect.

Also, the last time I used one of these products, I nearly poisoned our two cats.

Ideally, I should clean the drive and paths every 18 months.

It seems to be taking me longer to do it and wondered whether I should hire or purchase something similar to these

(1) Whirl-A-Way / Surface Cleaner – HydraFix Online

My pressure washer is an electric Briggs and Stratton.

If I purchased one, I would be thinking to buy just the 'head' and attach my own wand (brass, longish and quick connect) because they are a lot cheaper.

But some come with wheels and the others I assume (but don't know) must use a type of hovercraft effect.

Anyone have any experience on using surface cleaners.

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Jase2985

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#2836182 21-Dec-2021 07:43

i love a good surface cleaner. only ever used a karcher one, but its great because it keeps the water jets an even height above the surface and its as harsh as just the wand its self. its also way faster.

compound

88 posts

Master Geek

#2836183 21-Dec-2021 07:46

I have a bit of experience. Concrete is not likely to get damaged unless it is already in poor condition or you are cleaning with very high pressure ie over 4000 psi. Your little electric cleaner will suit something like the BAR1400 14 inch cleaner or smaller. Too big a cleaner for the waterblaster volume will end up doing a poor job since the rotation speed will be too slow. The only small unit with wheels would be the Mosmatic. The website is Australian but BE Pressure is in NZ (the actual manufacturer/wholesale supplier ). They have a NZ website and supply to dealers throughout the country.

Goosey

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#2836185 21-Dec-2021 07:47

I use both pressure washer and the occasional product from wet and forget (helps buy time... the last time I pressure washed was 2 years ago....and im just starting to see a need for a 2 day pressure washer bender (but nervous about frowns from the neighborhood as we go into water saving season.....but still, I need to get this done before the local council introduce water charges in about 6 - 8 months time).

Their store team are really helpful and will try and answer all your questions if you feed them the correct info about your circumstances.

alisam

830 posts

Ultimate Geek

#2836190 21-Dec-2021 07:55

Goosey:

I use both pressure washer and the occasional product from wet and forget (helps buy time... the last time I pressure washed was 2 years ago....and im just starting to see a need for a 2 day pressure washer bender (but nervous about frowns from the neighborhood as we go into water saving season.....but still, I need to get this done before the local council introduce water charges in about 6 - 8 months time).

Their store team are really helpful and will try and answer all your questions if you feed them the correct info about your circumstances.

Which 'store team' are you referring to? Wet and Forget?

timmmay

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#2836193 21-Dec-2021 08:03

If it's worked for 25 years I'd keep doing it, unless you're starting to see wear or damage you think is caused by the cleaning.

I do generally find physical contact such as a brush more effective than water blasting alone, however as the brush gets larger there's less force per square cm. Probably best to see if anyone has used one.

Cleaning products can help. When I wash the house I spray on wet and forget, brush it, leave it 5 mins, and wash it off, which is much more effective than water blasting.

eracode

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#2836195 21-Dec-2021 08:25

My understanding is that using a water blaster to get rid of mold etc on concrete can blast out the 'fines' (sand used in making) in the concrete, making it rougher so that next time the mold has more surface area on which to grow.

Wet n Forget certainly push this idea to sell more of their product.

Sometimes I just sit and think. Other times I just sit.

alisam

830 posts

Ultimate Geek

#2836290 21-Dec-2021 12:15

compound:

I have a bit of experience. Concrete is not likely to get damaged unless it is already in poor condition or you are cleaning with very high pressure ie over 4000 psi. Your little electric cleaner will suit something like the BAR1400 14 inch cleaner or smaller. Too big a cleaner for the waterblaster volume will end up doing a poor job since the rotation speed will be too slow. The only small unit with wheels would be the Mosmatic. The website is Australian but BE Pressure is in NZ (the actual manufacturer/wholesale supplier ). They have a NZ website and supply to dealers throughout the country.

Have you tried cleaners with and without wheels?

If so, which do you prefer?

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compound

88 posts

Master Geek

#2836302 21-Dec-2021 12:39

alisam:

Have you tried cleaners with and without wheels?

If so, which do you prefer?

I prefer wheels but I run a 20" version and 21litres per minute. Big volumes of water mean faster operation so though you use more water per minute than a smaller machine you get the job done faster so the time saved saves water. The little yellow 14"version has no wheels so it brushes over the surface meaning more chance of catching and getting knocked out of place. Also more arm effort than one with wheels to operate. Any version of surface cleaner matched to the waterblaster will do a better job than a standard nozzle. Commercial operator tests suggested up to 75% time saving and better finish than a standard 40 degree fan nozzle for a large driveway.

alisam

830 posts

Ultimate Geek

#2836584 22-Dec-2021 08:20

The Briggs and Stratton Specifications are:

Does this make a difference to the models suggested?

compound

88 posts

Master Geek

#2836993 22-Dec-2021 17:21

Unfortunately that waterblaster is only 4.1 litres per minute under operating pressure. Sure as Karcher says, it saves on the water useage, but it could take 6 times longer to do the same job so no real water savings against a larger machine. The low water usage plays badly against all the surface cleaners I know of as minimum is about 6-7 litres per minute. Way down at 4 lpm you will get pressure drop, blocking nozzles and bad striping due to low rotation speed. I think you will be disappointed trying a surface cleaner on a waterblaster that small is my personal opinion.

alisam

830 posts

Ultimate Geek

#2837120 23-Dec-2021 06:36

compound:

Unfortunately that waterblaster is only 4.1 litres per minute under operating pressure. Sure as Karcher says, it saves on the water useage, but it could take 6 times longer to do the same job so no real water savings against a larger machine. The low water usage plays badly against all the surface cleaners I know of as minimum is about 6-7 litres per minute. Way down at 4 lpm you will get pressure drop, blocking nozzles and bad striping due to low rotation speed. I think you will be disappointed trying a surface cleaner on a waterblaster that small is my personal opinion.

I feel a bit deflated now after spending time researching different models.

I had come to the conclusion I needed a small model with wheels.

I have searched for my water pressure model and none of the sites I have visited mention the 4.1 litres per minute, only the 12.1 litres per minutes.

I hope other readers will come across this topic and find it useful.

compound

88 posts

Master Geek

#2837146 23-Dec-2021 08:30

For your peace of mind the 4 litres comes from making a calculation of

required electric brake horsepower = (gallons per minute x psi) / 1460

(1.1 x 2000)/1460 = 1.5 horsepower, which would be about right for a motor wattage of 1380 watts

The max flow they claim is basically the water that could go through the machine if it had no nozzle to produce pressure, basically a useless figure that means nothing. For a machine that outputs 12 litres per minute it will require a 3hp or 2.2kW motor to run it at pressure. That translates to 15A plug as the motor will be drawing 13A or more.

alisam

830 posts

Ultimate Geek

#2859020 31-Jan-2022 10:19

Just a follow up on GPM/LPM.

For my Pressure Washer the specs are:

Below are the specifications for a Karcher (NZ Web Site) I have chosen at random.

From a web site I found this formula

(US Liquid) GPM = LPM * 0.26417205236

Therefore, GPM for the Karcher is 9.5 x 0.26417205236 = 2.5 GPM.

Looking at another Briggs and Stratton petrol, it has the same LPM specified.

The Briggs and Stratton uses '(max)' but the Karcher does not.

But looking at the Karcher Manual it is clearer:

How does anyone know the actual GPM/LPM coming put of the nozzle?

It isn't specified (as far as I can see) in most web site information or manuals. The word 'max' probably gives a clue that it is NOT the GPM/LPM coming out of the nozzle.

I've done quite a bit of searching on the web, but nobody seems to explain the difference between flow rate out of the hose and flow rate out of the nozzle.

I still need to buy a Surface Cleaner which is just the disk. But I need to know the size of a Pressure Washer that is domestic rather than commercial.

compound

88 posts

Master Geek

#2859178 31-Jan-2022 12:39

Nozzles are sized by orifice diameter which is the sum of (gallons per minute)x(square root of (psi/4000))

This number is a formula sum, not a diameter in mm or inches etc. All nozzles are sized on this calculation so if you have a QC waterblaster nozzle that is green, the numbers on it would be something like 25030 which means a 25 degree spray angle and 030 hole size. Red starts 00, yellow 15, white 40 and the last numbers are the orifice size eg 020, 025,030,035,040.......

So if your nozzle ended in 030 you can say by the nozzle chart that at 2500psi you will flow 2.37 gallons per minute. At 3000psi the flow would need to be 2.6 gallons per minute. Any extra flow would be bypassed internally in the pump as the regulator would be lifting or you would need more HP and achieve more pressure to flow the full amount of water as the nozzle is a fixed size.

I see inflated water flow figures a lot and they can get away with the white lie as they dont claim the flow rate at that pressure. Open gun with no nozzle and you might get that flow rate but once you put a nozzle on you will not see the same flow as internal restrictions (the nozzle is the biggest) will reduce the flow achieved out the pointy end.

Watch out for when they say "max"on the pressure figures as well. Usually means what the pressure gauge reads on the unloader spike, not the pressure you get continuously while pulling the trigger.