what to look for in a water blaster ?

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199 posts

Master Geek

#1408897 18-Oct-2015 22:40

Sideface:
xlinknz: ... I'm leaning towards the Bosch as it has a more powerful motor, higher psi but for some reason a slightly less flow rate, any ideas ?! ...

The Venturi Effect

Pump fluid through a smaller hole - you get get higher pressure, and less flow.

Ummm no. You get higher velocity and less pressure in the neck of a venturi. The pressure is the force of the water as it exits the restriction divided by the cross-sectional area of the restriction - not the pressure in the restriction itself which is what the venturi effect is. Power is the limiting factor for pressure - you can get a force at the nozzle by using a smaller restriction but the pressure doesn't change because of the smaller opening. That's why it the volume or power needs to be taken into account for the purpose of purchasing - pressure alone doesn't tell the full story.

andrew027

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#1433778 24-Nov-2015 10:38

I just found this (still recent) thread. I had been looking for one myself and started by listing all the jobs I'd use it for: a moderate sized wooden deck on one side of the house; concrete patio at the back; concrete driveway/parking pad at the front; stone veneer walls at the front and back that get quite a bit of moss and mould on them; wooden fence around most of the property that also looks a bit green in sheltered places; wooden outdoor furniture and built in bench seats; the barbecue; the car; my road and mountain bikes; washing the house and windows (three storeys in one front corner, two along most of both sides, and one in the back).

I decided on Karcher based on availability, future serviceability, the range of accessories, and a couple of minor features that appealed. The size of my house ruled out anything lower than the K4 and the K5 or up was recommended. At that end of the range they have the aluminium pump, which I preferred and I went with the K6 as it will run longer than me before needing a break and comes in a kit with several accessories included (buying the K5 plus the accessories separately works out to be about the same price).

Karcher recently opened their own store in Lower Hutt and the guy there was very helpful explaining spec.s and features, etc. but admitted that it would be cheaper buying from one of the big hardware stores. I went to Mitre 10 Mega and their price for the K6 kit was only about $5 cheaper than at Karcher but I also managed to talk the guy into throwing in the telescopic spray lance (which will be useful for the high front section of my house) that sells for around $230.

So far I've cleaned the car, and the concrete back patio and outdoor furniture before the first barbecue of the season. I'm very happy with it. This weekend I'll do the much larger front driveway, the stone walls and the wooden deck, so that will be more of a workout for both of us.

richms

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#1433781 24-Nov-2015 10:42

TonyR1973:
Someone should tell Ohm's Law that it's wrong.

Ohms law only applies to resistive loads. Motors are not.

Richard rich.ms

xlinknz

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#1434117 24-Nov-2015 20:49

andrew027: I just found this (still recent) thread. I had been looking for one myself and started by listing all the jobs I'd use it for: a moderate sized wooden deck on one side of the house; concrete patio at the back; concrete driveway/parking pad at the front; stone veneer walls at the front and back that get quite a bit of moss and mould on them; wooden fence around most of the property that also looks a bit green in sheltered places; wooden outdoor furniture and built in bench seats; the barbecue; the car; my road and mountain bikes; washing the house and windows (three storeys in one front corner, two along most of both sides, and one in the back).

I decided on Karcher based on availability, future serviceability, the range of accessories, and a couple of minor features that appealed. The size of my house ruled out anything lower than the K4 and the K5 or up was recommended. At that end of the range they have the aluminium pump, which I preferred and I went with the K6 as it will run longer than me before needing a break and comes in a kit with several accessories included (buying the K5 plus the accessories separately works out to be about the same price).

Karcher recently opened their own store in Lower Hutt and the guy there was very helpful explaining spec.s and features, etc. but admitted that it would be cheaper buying from one of the big hardware stores. I went to Mitre 10 Mega and their price for the K6 kit was only about $5 cheaper than at Karcher but I also managed to talk the guy into throwing in the telescopic spray lance (which will be useful for the high front section of my house) that sells for around $230.

So far I've cleaned the car, and the concrete back patio and outdoor furniture before the first barbecue of the season. I'm very happy with it. This weekend I'll do the much larger front driveway, the stone walls and the wooden deck, so that will be more of a workout for both of us.

In the end I went for a Nilfisk C130.2-8 [spec'ed between a Karcher 3.8 and 4.2] as it was down to $300 [from $500] at Mitre 10 as the new version has wireless pressure control on the lance. As much as I was tempted by the Bosch a uk 'which' mag comprehensive test reviewed the Nilfisk better. Despite the plastic finish it surprisingly is well built and came with a 8m hose. All that said I found that specifications on water blasters are somewhat misleading e.g. one brand will have a max flow rate another a rated flow rate. So far it has done what is expected. Note before buying I tried the neighbors Karcher entry level K2.090 which actually worked well despite the difference in specs. In hindsight I wouldn't place import on specs, get what does the job.

Warning: Its obvious Karcher and Nilfisk in particular make them money from the accessories. Most accessories are very expensive for what they are.

richms

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#1434123 24-Nov-2015 21:01

Check amazon for the accessories as well. I found the hover UFO cleaning thing for waaaaay less on there even when including the reshipping.

Richard rich.ms

Technofreak

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#1434218 24-Nov-2015 23:21

xlinknz: All that said I found that specifications on water blasters are somewhat misleading e.g. one brand will have a max flow rate another a rated flow rate. ...... Note before buying I tried the neighbors Karcher entry level K2.090 which actually worked well despite the difference in specs. In hindsight I wouldn't place import on specs, get what does the job.

Just like Peak and RMS when it comes to quoting stereo power outputs.

Or DIN and SAE when it comes to horespower

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andrew027

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#1434319 25-Nov-2015 08:28

xlinknz: Warning: Its obvious Karcher and Nilfisk in particular make them money from the accessories. Most accessories are very expensive for what they are.

richms: Check amazon for the accessories as well. I found the hover UFO cleaning thing for waaaaay less on there even when including the reshipping.

This is why I bargained hard to get the telescopic lance for free when buying the K6 (just shy of $1000, but came with one of the "Racer" hard surface cleaner heads and a soft brush, the "vario power" and high pressure "dirt blaster" lances, and two bottles of cleaner - one for concrete/stone and one for the car - so about $350 of accessories already included). With the lance I have pretty much everything I need, although I might buy a bottle of the wood cleaner.

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timmmay

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#1439353 2-Dec-2015 16:17

Which of these waterblasters are better for general round the house cleaning - deck, concrete (it's got a bit of moss on it), car, fence. Karcher (specs here) or Bosch (I think it's this one)? NB: getting on flybuys, topping up with a few dollars as I don't have quite enough points and some are expiring soon.

Consumer say Karcher wands are short and give you a sore back but didn't look at the Bosch.

Quick specs

Karcher (includes two lances):

1600psi; 6.0 litres per minute
1.4kw motor
Corrosion free for life pump
6m quick high pressure hose
High pressure lance
Dirtblaster lance
Wash brush
Car shampoo concentrate 500ml
Detergent injector hose
2 year warranty

Bosch (includes one lance I think, connects to Karcher accessories, which suggests that Karcher is the big player in this area):

Pressure: 130 bar / 1885 PSI
Flow rate: 400 litres/hour
Extremely powerful 1,900W motor
Versatile high-pressure 6m hose and 5m cable length
Rubber tyre wheels for quiet and easy mobility
Bosch Auto-Stop system ensuring energy efficiency and all metal pump
Self-priming, detergent suction system
Ready to use out of the box, no assembly required
Fold down handle, reducing storage space by 40%
Comes with rotary nozzle, 550ml detergent bottle, fixed brush, Karcher adaptor and variable flow patio cleaner, all of which are carried on the unit so all equipment is close at hand at all times
2 year warranty

MikeAqua

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#1439453 2-Dec-2015 18:37

Must have features in a water blaster

1) Wand length to suit your height for cleaning path driveways etc - most of them are too short for taller people.
2) In my opinion a petrol engine. On balance I think they are easier than dealing with extension cords, and you can reduce pressure by pushing the throttle to idle.
3) Detergent injection bottle

Mike

xlinknz

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#1440929 5-Dec-2015 11:30

timmmay: Which of these waterblasters are better for general round the house cleaning - deck, concrete (it's got a bit of moss on it), car, fence. Karcher (specs here) or Bosch (I think it's this one)? NB: getting on flybuys, topping up with a few dollars as I don't have quite enough points and some are expiring soon.

Consumer say Karcher wands are short and give you a sore back but didn't look at the Bosch.

Quick specs

Karcher (includes two lances):

1600psi; 6.0 litres per minute
1.4kw motor
Corrosion free for life pump
6m quick high pressure hose
High pressure lance
Dirtblaster lance
Wash brush
Car shampoo concentrate 500ml
Detergent injector hose
2 year warranty

Bosch (includes one lance I think, connects to Karcher accessories, which suggests that Karcher is the big player in this area):

Pressure: 130 bar / 1885 PSI
Flow rate: 400 litres/hour
Extremely powerful 1,900W motor
Versatile high-pressure 6m hose and 5m cable length
Rubber tyre wheels for quiet and easy mobility
Bosch Auto-Stop system ensuring energy efficiency and all metal pump
Self-priming, detergent suction system
Ready to use out of the box, no assembly required
Fold down handle, reducing storage space by 40%
Comes with rotary nozzle, 550ml detergent bottle, fixed brush, Karcher adaptor and variable flow patio cleaner, all of which are carried on the unit so all equipment is close at hand at all times
2 year warranty

Clearly one has superior specifications but without knowing the cost to you of both is is not possible to say which you should get. The question would appears to why wouldn't you get the Bosch ?

timmmay

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#1440942 5-Dec-2015 12:15

The Karcher is like $70, the Bosch $90. We had a look at them today, the Bosch has a longer handle and would probably be more comfortable to use. Neither are especially powerful, but we just want to clean deck, concrete, and car, so should be fine. The Bosch looks like better quality. I think I'll get that one :)

Technofreak

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#1473786 18-Jan-2016 13:44

I splashed out on the weekend, (excuse the pun) and finally bought a water blaster.

I vacillated between electric or petrol and finally decided on electric.

Then the decision was which brand, Karcher had a reputation for poor pump life. A lot of reviews favoured the metal pumps as used by Nilfisk and other brands, as the metal didn't split like the plastic Karcher ones. however they could corrode when not used on a regular basis.

I looked at Stihl, Bosch, Nilfisk and Karcher.

I was told that until recently the Nilfisk pumps were better than the Karcher pumps, but recently Karcher had leap frogged Nilfisk. The Karcher pumps are now made of a composite material for better life and don't have any corrosion issues.

In the end I went with a Karcher K5 Premium which came packaged with the dirt plaster, extra lance extension, power dirt blaster, "Racer" T350 patio cleaner and other various attachments.

I wanted something that would keep on going and would clean a reasonable area in a given time. The K5 covers nearly double the area of some of the smaller models. Also with a brand like Karcher there is plenty of after market availability of attachments etc.

I spent about double what I had initially thought I would spend however I think I would have been disappointed with anything smaller. I did briefly consider the K6 but decided I didn't need the extra "horsepower".

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andrew027

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#1473816 18-Jan-2016 14:05

Technofreak: I did briefly consider the K6 but decided I didn't need the extra "horsepower".

I got the K6 because I do need the extra power when washing the house (as mentioned earlier it's three storeys in the front and two along most of the length) which I do at least once and usually twice a year. Add to that it will run a lot longer than the lesser models so I can do decks, patios, fences, driveways, the car, etc. all in one day.

Another thing I used it for a couple of weeks ago was cleaning out the wheelie bin, which had a layer of built-up stinky crud on the bottom. I had previously tried (unsuccessfully) cleaning it with a detergent and a stiff broom but the dirt blaster lance made quick work of it.

BTR

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#1473819 18-Jan-2016 14:07

I have a Nilfisk and it works a treat, there is one particular attachment that you do not use on paint as it will remove it. It cam with two different nozzles as well as a attachment for spraying detergent.

Works a treat and is a lot better than my mates rubbish Karcher.

bluedisk

226 posts

Master Geek

#1473852 18-Jan-2016 14:35

We have the Karcher K5 with Patio cleaner. So far I have used it for cleaning 4 different decks in various states of disrepair in the last few months. If you use it as recommended it does a very good job of cleaning up old decks, even ones that I thought were shot. My process has been to first spray with Cabots Deck Clean onto a wet deck. Then leave for about 10 minutes, then use the patio cleaner head on the Karcher. On really manky/ fungusey timber, I'll repeat the process then coat with decking oil. Its way easier than I was expecting.

One of the decks was on Waiheke Island, where the owner had a water shortage and I was surprised at how water efficient this machine was.

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