Soak car before using foam gun?

[Setec Astronomy]

But, if you then look at the same area after foaming, some more dirt is removed - to my mind, this is evidence enough the the foam does remove some additional dirt...

I'm just playing Devil's Advocate here...if you had simply, after drying, gone over it with the pressure washer again (no foaming), would it have looked the same as after the first picture, or after the second, or somewhere in-between?

In some of these recent threads, we (the forum members) seem to be treading into areas that are beyond objective "best practice" and into subjective/semantic pre-soak routines that are of perhaps unverifiable efficacy.

In my mind pressure washing will remain the best pre-treatment before contacting the paint with wash media, whether that pressure washing is accompanied by foam pre/post treatments or not.

[shagnat]

No science here, but, IMHO, pressure washing CAN be detrimental for a first step or even 2nd step, in rare cases, to clean a car.... my way of thinking is the pressure of the water pushing the dirt off the car could definitely cause scratched paint because the pressurized water could and would push "some" of the surfactants into the clearcoat and/or paint..... just my 2 cents.

[Bunky]

If suspect if that was happening they are using a higher powered gas powered washer and have it too close to the paint like how someone uses it to clean a deck or concrete.

[shagnat]

If suspect if that was happening they are using a higher powered gas powered washer and have it too close to the paint like how someone uses it to clean a deck or concrete.

Agreed. And as we all know, some folks think if a little is good, then MORE is better... NOT always

[PiPUK]

They're all either around 7 or close to 14 at 13.5. I originally didn't use the Iron X Snow Soap or the Bug Squash but slowly added them in. When I added in the Iron X I ensured that it still reacted with areas iron was present. The snow soap isn't as strong as normal Iron X but when I rinse the car off there is still some purple in the foam being rinsed off. And last I added the bug squash, I'm still trying to determine if it's better to add that to the foam lance or if it's more beneficial sprayed onto the surface of the car by itself. So far it seems like it's working pretty well and by putting it in the foam lance it does save time.

Obviously every car is different so it's hard to compare side by side. It may add no benefit at all but the cars seem to come cleaner easier during the following 2BM wash - and the foam lasts a bit longer.

As a chemist/manufacturer, I would never recommend all this mixing. Very quickly - you are compromising IXSS with the high pH you are producing. You are wasting money because your ISXX and degreaser/APC/Bug wash all have similar ingredients which you are duplicating. APC and degreaser can fundamentally be very similar, so again potentially duplicating. You are also compromising the safety of the wash because you are taking some nice safe products and adding aggressive things to them (which is also wasting money - why not just use aggressive all round rather than spending money on expensive safe stuff?). More than this again, you are potentially compromising the chemistry because you are almost certainly putting a load of sodium ions into the mix where ISXX specifically does not use said chemistry because of the obvious performance inhibition. Simply put, you are basically playing guesswork and I can guarantee you that you could do better if you just focused on finding a professionally formulated product that met your needs.

I'm just playing Devil's Advocate here...if you had simply, after drying, gone over it with the pressure washer again (no foaming), would it have looked the same as after the first picture, or after the second, or somewhere in-between?

In some of these recent threads, we (the forum members) seem to be treading into areas that are beyond objective "best practice" and into subjective/semantic pre-soak routines that are of perhaps unverifiable efficacy.

In my mind pressure washing will remain the best pre-treatment before contacting the paint with wash media, whether that pressure washing is accompanied by foam pre/post treatments or not.

Pressure washing once, drying and then doing it again is not going to do any good. If you pressure wash properly first time, you have removed everything that will come off with that method (or pretty darned close). By your suggestion, if you just keep pressure washing then the dirt will eventually all be gone - this is not the case, you need the detergents.

No science here, but, IMHO, pressure washing CAN be detrimental for a first step or even 2nd step, in rare cases, to clean a car.... my way of thinking is the pressure of the water pushing the dirt off the car could definitely cause scratched paint because the pressurized water could and would push "some" of the surfactants into the clearcoat and/or paint..... just my 2 cents.

In practice, none of this is of any significance. When you hit the surface with the water, the dirt is not being rubber against the surface, it is almost being blown off it. At some point, you have to get that dirt off there - how do you propose to do it? The use of the washer cannot intelligently be argued to be more aggressive than a physical wash mitt/sponge. Those are scenarios whether you actually have someone creating a big wet sanding pad - yet many proponents will say this causes no damage. Arguments based on lubrication and suspension are all well and good, but it would be scientific fact that these methods are (to one degree of another) resulting in abrasive material being rubbed against the surface. If you can come up with a method of getting the dirt off with low pressure and non-contact methods, you are right. Until we do so, non-contact methods will almost always be less aggressive that manual ones. As for surfactants/detergents being 'pushed' into the paint - no. That;s a bit like saying that throwing a football at a wall will push some of the football into the concrete. The surfactant molecules are miles too big to penetrate the paint, even with a pressure washer. In any case, given that H20 is practically the smallest molecule your paint will encounter - why would you assume that surfactants (which are 10s to hundreds of times larger) are the ones which would penetrate?

[PiPUK]

Oh and more to the point of the thread...

Cleaning is predominantly driven by how effectively you 'wet' the soil you are attempting to remove. If you wet it adequately, you are most of the way to removing it. This is what you would learn in cleaning 101. So it follows that wetting the surface is almost always a good first step. My process will almost always involve an initial wetting/pressure wash to get rid of the large/loose soils. This is then followed by a prewash of some kind (whether it is a spray or a foam) and then a pressure wash which will get rid of much of the stuff that the pressure washer alone did not. In the conditions we get, this will rarely be enough as road films are tenacious buggers. So I will then do a contact wash which will remove everything else. What this means is I get as much bang for my buck as possible. If I put wash solution onto a dirty/dry car, I am wasting some of it acting on soiling which could be removed by water alone. Moreover, I will have more issues with it drying out (I prefer to pre-spray, rather than foam). By leaving the bucket wash to the end, there is as little soil on the surface as possible and thus the least chance of abrasion of the surface. I am not saying that this is the most complex methodology available but this is sticking to sound fundamentals and I believe that a professional process should be based around this.

[Jeremy1976]

I pressure wash, foam gun, let dwell, then 2 bucket.

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[idriveblackcars]

I pressure wash, foam gun, let dwell, then 2 bucket.

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Exact same method here. 2 black cars zero swirls. I wouldn't wash my car without a pressure washer. With the correct nozzle it's the best way to go.

[Eldorado2k]

Oh and more to the point of the thread...

Cleaning is predominantly driven by how effectively you 'wet' the soil you are attempting to remove. If you wet it adequately, you are most of the way to removing it. This is what you would learn in cleaning 101. So it follows that wetting the surface is almost always a good first step. My process will almost always involve an initial wetting/pressure wash to get rid of the large/loose soils. This is then followed by a prewash of some kind (whether it is a spray or a foam) and then a pressure wash which will get rid of much of the stuff that the pressure washer alone did not. In the conditions we get, this will rarely be enough as road films are tenacious buggers. So I will then do a contact wash which will remove everything else. What this means is I get as much bang for my buck as possible. If I put wash solution onto a dirty/dry car, I am wasting some of it acting on soiling which could be removed by water alone. Moreover, I will have more issues with it drying out (I prefer to pre-spray, rather than foam). By leaving the bucket wash to the end, there is as little soil on the surface as possible and thus the least chance of abrasion of the surface. I am not saying that this is the most complex methodology available but this is sticking to sound fundamentals and I believe that a professional process should be based around this.

I agree with this.^
That's similar to the steps I follow, except I prefer to begin by pre spraying the whole vehicle with Megs D114@1:128 with a pump sprayer while it's still dry as opposed to after rinsing it. I feel this helps it stay and cling onto the paint instead of having the chance to run down the wet panels. Doing this, especially onto a dirty vehicle makes a good difference in how much grime comes off during the initial rinse, prior to touching the paint with the wash mitt.

Of course it helps if the paint is already well maintained and waxed.. It's also ideal to do this when the paint is cool to the touch and not in direct sunlight, similar to how you would treat cleaning wheels. [when cleaning wheels, I always prefer to spray wheel cleaner onto a dry wheel as opposed to a pre rinsed wheel, especially if I'm using a product like Wheel Brightener, that way it makes direct contact with the brake dust]

[PiPUK]

I agree with this.^
That's similar to the steps I follow, except I prefer to begin by pre spraying the whole vehicle with Megs D114@1:128 with a pump sprayer while it's still dry as opposed to after rinsing it. I feel this helps it stay and cling onto the paint instead of having the chance to run down the wet panels. Doing this, especially onto a dirty vehicle makes a good difference in how much grime comes off during the initial rinse, prior to touching the paint with the wash mitt.

Of course it helps if the paint is already well maintained and waxed.. It's also ideal to do this when the paint is cool to the touch and not in direct sunlight, similar to how you would treat cleaning wheels. [when cleaning wheels, I always prefer to spray wheel cleaner onto a dry wheel as opposed to a pre rinsed wheel, especially if I'm using a product like Wheel Brightener, that way it makes direct contact with the brake dust]

Of course the counter argument is that applying to a dry surface means that the product cannot (as you say) run off. If the liquid does not run off, the dirt does not go with it and (particularly in warm weather) you can end up with the whole lot drying in place before you wash it off. This is also applicable to high foam products and it is something we see misunderstood by so very many people. We get guys looking for a product which clings for 30 minutes and don't understand that this is rubbish. If the wash solution isn't moving or doesn't have the interfacial region replenished with chemicals, nothing happens. A good foam product should break down in a reasonable time period. You get some contact time and then the soiling starts to move as the foam breaks down and run off. To double the effect, breaking down means that fresh product, presently trapped in the foam, is able to move to the surface and continue the cleaning. With a foam where you end up with piles of stable foam on the ground, the vast majority of the active product has done nothing more than make a foamy mess on the ground - it never got near the paint.