What Matter Most, Water Pressure Or Water Volume?

[lovenhim]

Hello folks. How is everyone doing today? I was curious about something. Now, this question is brand and is geared more for the DIY person than the professional detailer. When washing a vehicle, which is more important, pressure or volume? I do not have a pressure washer and simply use a good ole' large and heavy 3/4 inch water hose. I know that some people like to spray their car while others like to float water over it and let the sheer volume of water and gravity do the work. Some use a fine spray and pressure to wash the car and then do a final rinse with water flow to sheet water off rather than have it beed. Here is what I am wondering, if water volume is important and means more than pleasure, would not a simple brass flow valve with a 1/4 valve work better than a fancy expensive nose? Thanks for the help.

 

[Jon TDS]

Hi there! Welcome to AG. It differs from person to person. One of Mike Phillips' video in washing his car is actually by using a garden hose. Some benefits of pressure washer are use of less water, pressure when you need them like for wheel wells, more foam to lift some contaminants, etc.

Sent from my Mi A1 using Tapatalk

 

[SWETM]

When you are looking on the PW specs. The water volume is IMO the most important to compare with.

When compare when useing a hose. The mix of the highest pressure you can get without effecting the water volume would I look for.

 

[Bruno Soares]

Yeah, you don't want super high pressure for car washing but higher volume is better. But don't go for something with so much volume that it uses the same as a garden hose, you want to save some water while getting more cleaning power due to added pressure.

 

[UncleDavy]

It depends on the situation. Good pressure will blast dirt and salt off of the surfaces of the paint so less contact with the wash mitt is required. A pressure washer will also use less water but it does not rinse very well. The good ol’ garden hose with no nozzle is the best way to rinse. The flood of water will take all of the suds with it and if the car has some kind of coating, most of the water will roll off.

 

[DaveT435]

Spray from a good nozzle works fine. When using a garden hose the volume will be there, if you switch to a pressure washer then you would want to look at volume. The only time I sheet the water is when I'm done washing the car. For the most part it's the first drying step. If you have a good LSP on the car by using the sheeting method you can get 90% plus of the water off the car.

 

[lovenhim]

I think I need to clarify a bit. I do not own a preasure washer and I do not plan to purchase one. What I am interested in is using our 3/4 inch garden hose. Am I better off using a nossle which provides higher water preasure, or one that allows a large volume of water flow?

 

[DaveT435]

I think I need to clarify a bit. I do not own a preasure washer and I do not plan to purchase one. What I am interested in is using our 3/4 inch garden hose. Am I better off using a nossle which provides higher water preasure, or one that allows a large volume of water flow?

A regular adjustable nozzle is fine. No matter what setting you choose you'll have plenty of volume and it will give you a variety of pressures and pattern for different jobs. Usually high pressure for initial rinse lower pressure wider pattern for rinsing.

 

[Desertnate]

I think I need to clarify a bit. I do not own a preasure washer and I do not plan to purchase one. What I am interested in is using our 3/4 inch garden hose. Am I better off using a nossle which provides higher water preasure, or one that allows a large volume of water flow?

I say both!

I've got one of those nozzles with multiple settings. When I'm blasting off bugs, break dust, or heavy dirt, I'll use the high pressure "jet" setting. While rinsing off soap I'll use the "spray" setting. When I've finished washing, I'll go around the car with the nozzel on the "flood" setting and flood rinse the car which, when it's wearing a coating, leaves it nearly dry.

 

[LSNAutoDetailingLSNAutoDetailing is verified member.]

I do not own a pressure wash. There are two types of wash which Mike Phillips outlines, 1.) Gentle Wash and 2.) Aggressive Wash. Mike once stated it really doesn't matter, regular hose or pressure wash, it's following the entire process which removes bonded contaminants.

When I first started I would take a vehicle to a coin opp and use the pressure washer. What I noticed was the pressure washer never got off anything that I thought it would. After going through the routine for an aggressive wash, as outlined below, I found that step unnecessary and time consuming. Long answer to your questioning, IMO, a pressure washer is not required.

When a car comes in that hasn't seen me before, or is absolutely filthy due to neglect, (years of bugs, tar, etc..) a pressure wash really isn't going to do much. I typically follow these steps for an aggressive wash:

Once this vehicle as undergone this process, it's really negotiable whether a pressure washer or regular hose is going to make a difference.
1.) Wheels
2.) Wheel Wells
3.) Engine / Engine Bay
4.) Tarminator on bumper cover, leading edge of hood, rockers. I use McKee's Bug Scrubber and remove all the baked stuck on stuff. This works great for the melted crack-filler they use to repair the roads, and ends up on the sides of the car, looking like black string cheese.
5.) Pre-Wash to remove the tarminator
6.) Rinse vehicle
7.) Iron-X ---> Let it dwell, go right to foam gun, don't bother rinsing off the iron-x.
8.) 2BM Wash with wash mitts
9.) Clay --> This will remove bonded contaminants
10.) Compound/Polish/AIO
11.) LSP
12.) Final detail trimings (plastics, under hood, door jams, wheels, tire dressings, exhaust tip cleaning, windows)

For Gentle wash, I wouldn't use a pressure wash. Gentle wash should be:

1.) Wheels/Wells
2.) Rinse
3.) Foam
4.) 2BM
5.) Blow Dry
6.) QD or topping of LSP - < Optional>

The idea of the gentle wash is a maintenance wash. You don't want to use so much pressure that you degrade your LSP, to include trim, moldings, etc.

 

[glen e]

Water pressure for spreading/activating water based coatings, like Hydr02, water volume to Rinse a car.....In my mind, it's that simple.

 

[FUNX650]

What I am interested in is using
our 3/4 inch garden hose.

Am I better off using a nossle which
provides higher water preasure, or one
that allows a large volume of water flow?

•IMO:
-Your hose can only supply the amount of
water volume/water pressure that’s available
at the hose bib.

-With that in mind:
Hose nozzles don’t increase the amount of
water volume/pressure, per se; but, a hose
nozzle—one that adjusts to different types of
“streams”—can increase the velocity of the
water by accelerating it through the nozzles’
specially designed (manufacturer specific)
narrowed-channels inside the nozzles.

{This is what’s known as harnessing the
“Bernoulli Principle” (Re: fluid dynamics)}


Nowadays...
•I stay away from brass nozzles (lead possibility)

•Accordingly, my favorite adjustable nozzles are:
-Gilmour Full Size Zinc (pistol style)
-Bon-Aire Aluminum (fireman-style)


Bob

 

[Farmallluvr]

I use a rubber flex nozzle for rinsing,,you push it down with your finger and it flows out like an open hose without the wasting of water when you are not using it.
I also like to use the pistol grip style that is common as I like to blast off bugs,crap off the wheels and wheel wells as well.
The side mouldings,around the mirrors,door handles, window trim and where the bumper covers meet the fenders/rear quarters all trap dirt as well so I like to give a good strong rinse in those areas.