# BH Auto Foam dilution ration in a pump sprayer



## FallenAngel (Oct 24, 2015)

Hey guys, just got 5L of BH Auto Foam and I will use it as a prewash trough pump sprayer. What is a correct dilution ratio, if i use 2L of water in a sprayer? Is 150ml in 2L of water too much ? I want it to remove as much as it can but still to remain LSP safe. Thanks in advance :car:


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## Kimo (Jun 7, 2013)

8% is best I find

Not too bad car then 4%


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## sm81 (May 14, 2011)

4-10% is good. Like Kimo said 8% is recommended if car is dirty.


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## clav604 (Dec 25, 2012)

I do abot 9-10% on bottom of cars


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## FallenAngel (Oct 24, 2015)

Thanks for your replies, 8% it will be .


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## great gonzo (Nov 4, 2010)

I use 350ml in a 5 litre spray bottle. This works extremely well. Couldn't get on with it at all as a snow foam tho what ever the dilution rate. 

Gonz.


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## steelghost (Aug 20, 2015)

It's worth mentioning that "LSP safe" is not a line that you either cross or don't cross - different LSPs will be more or less affected by detergents, and what is "LSP safe" for one will not be for another. In top of this, a given wash product may have a different effective strength depending on factors like how hard your tap water is, and the temperature you apply to the vehicle at.

Try it out, let everyone know how you get on


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## Blackmass (Jun 2, 2015)

I'm a thicko so please bear with me. I struggle with the ratios.

Say I want to make 3 litres with 8% of the Auto Foam. Would it be 240ml of Auto Foam and 2760ml water?
Or 3000ml AND add 240ml Auto Foam?


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## Kimo (Jun 7, 2013)

Blackmass said:


> I'm a thicko so please bear with me. I struggle with the ratios.
> 
> Say I want to make 3 litres with 8% of the Auto Foam. Would it be 240ml of Auto Foam and 2760ml water?
> Or 3000ml AND add 240ml Auto Foam?


Option A


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## jk1714 (Jun 26, 2014)

Been wondering about this myself. Thanks


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## azreal (Sep 24, 2012)

*Pressure washer dilution*

Just ordered 5l myself

I have a direct hoses snow foam lance on my nilfisk

I have added about 100ml in the 1 l bottle. Topped up with water.

The foam produced is quite thin. I have rotated all the way to - and + and cannot get thick foam like with the demon foam I used to have

What am I doing wrong.

Thank you


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## FallenAngel (Oct 24, 2015)

BH Auto foam is not a thick foam, it's dsignated to be thinner and to run off the car faster and pull the dirt with it. It's main selling point is a great cleaning power. If you want you can try neat Auto foam on your lance, thats what a BH recomends.


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## azreal (Sep 24, 2012)

Thank you. I did see it pulled the dirt of really well. 

Will try it neat later on


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## tigerspill (Nov 28, 2015)

What pump sprayer do people recommend? Is this a better option than using the poser washer. It certainly seems less work/


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## Kimo (Jun 7, 2013)

tigerspill said:


> What pump sprayer do people recommend? Is this a better option than using the poser washer. It certainly seems less work/


Wilko £2 one does me well

Lasted longer than my mesto already lol


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## adjones (Apr 24, 2013)

There is a disconnect here. A pump sprayer dilutes with water. A foam Lance dilutes with water AND air. For comparable strength, you should be much weaker in a pump sprayer than in your foam lance bottle.

For example, pump sprayer, 100ml in 1lit gives 10 percent active on the paint. 100 ml in a foam Lance bottle at max foam setting is 10 percent x 10 percent (by the foam lance) gives 1 percent active. If you create a foam, you almost certainly have further dilution. Being very conservative, let's say a factor of 2. This gives 0.5 percent active on the paint. That means that the pump sprayer, with the same dilution in the bottle, gives 20x the strength on your paint.


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## 11redrex (Sep 11, 2014)

What he said. Neat in a foam lance, unless you've got a flash PW can turn your water pressure down on. 
You could work out your percentage if you knew exactly how much water is going through your lance in the time it takes to empty the bottle.
EG, my cheapo karcher K2 pumps out 6 litres of water a minute apparently. It takes around 5 minutes to empty the 1 litre my lance tank on full foam setting, so that's 30 litres of water (eek !) or 16%. 

100ml of foam with 900ml of water gives you 10%. You'd need to put 160ml in a hand sprayer/foamer to get 16%, ie the same strength, but you still won't get the thick foam we all like so much  through a hand sprayer or hand foamer as you would with a PW because of the lower pressure going through the nozzle. 


Mesto foamers are poop. And if you think demon foam is thick, wait till you get a proper foam off your lance !


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## steelghost (Aug 20, 2015)

The only factors in the dilution or "panel impact ratio" or PIR, as Bilt Hamber call it, is the ratio of water to Auto Foam (or whatever other snowfoam you might be using). The Auto Foam doesn't dissolve in the air, so the fact the solution is made into a foam has no impact on the PIR. Note that this not the same as saying it has no impact on the cleaning.

The area where there is real uncertainty is how much water the lance combines with whatever you put in the bottle. Unless the dial is marked with dilution ratios, this is a matter of experimentation and measuring flow per minute of foam, and how much the fluid in the bottle drops over the same period. By contrast, when using a pump sprayer the PIR is what you put on the bottle.


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## adjones (Apr 24, 2013)

steelghost said:


> The only factors in the dilution or "panel impact ratio" or PIR, as Bilt Hamber call it, is the ratio of water to Auto Foam (or whatever other snowfoam you might be using). The Auto Foam doesn't dissolve in the air, so the fact the solution is made into a foam has no impact on the PIR. Note


I would strongly debate this. The reality is that, in a foam, a lot of the chemical is isolated from the surface. It is trapped in the foam by all that air. It does not contact the surface so that means that the effective concentration is decreased. IF (BIG IF) the foam breaks down before it hits the ground, they have a point, but that isn't how snowfoams behave. I have never seen someone use a snowfoam and not show visible foam on the ground. This simple truth means that the effective concentration HAS been reduced by the air. I don't see how a scientific consideration can conclude otherwise.

In any case, their PIR clearly says that you should use the product miles stronger in a lance bottle, than in a pump sprayer. I don't think anyone can reasonably debate this.


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## steelghost (Aug 20, 2015)

One can reasonably debate anything  

The foam itself, which is fully in contact with the paint, is composed of the detergent diluted in whatever amount of water. It absolutely is in contact with the paint. There is nothing else for it to be in contact with! The fact that air is trapped in it is pretty much irrelevant to this point. The idea of a snowfoam is that it increases the dwell time of the detergent on the paint (or more accurately, on whatever muck is attached to the paint) increasing the ability to clean it off. 

You use the term "effective concentration" - honestly, how do you think that differs from the actual concentration of the detergent in the water? The answer is, it doesn't. The fact that a snowfoam allows some of the detergent to drip off onto the ground shows that snow foaming wastes some detergent - but then so does washing with a mitt. 

If BH say to use Auto Foam at higher concentration in a lance bottle, that's because they know that the average lance will add 10-20 times the volume of detergent in water, so if you pre-dilute the detergent in the bottle, what hits the panel will be further diluted, possibly by too much to have a useful effect. How much of course will depend on the PW, the lance and its setting - whereas in a spray bottle, whatever you put in the bottle is what lands in the panel. Let's assume you manage to get your lance set up so that the amount of water and detergent landing on the panel is exactly the same as with the pump sprayer. The cleaning effect due to the *detergent* is exactly the same for both - for as long as the detergent remains in contact with the panel. The foam will likely extend this (that's the point, after all) and hence may exhibit better cleaning due to that - I have also seen it written that the bursting of the bubbles gives additional cleaning power, and I can't comment on this. But the fact that a foam is being used to bring a certain concentration of detergent in contact with the panel does not change matters vs simply spraying that liquid on directly. It cannot - there is nowhere else for the detergent to go. The entire liquid is composed of the same concentration of detergent in water.


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## adjones (Apr 24, 2013)

steelghost said:


> One can reasonably debate anything
> 
> The foam itself, which is fully in contact with the paint, is composed of the detergent diluted in whatever amount of water. It absolutely is in contact with the paint. There is nothing else for it to be in contact with! The fact that air is trapped in it is pretty much irrelevant to this point. The idea of a snowfoam is that it increases the dwell time of the detergent on the paint (or more accurately, on whatever muck is attached to the paint) increasing the ability to clean it off.
> 
> ...


I think reasonable debate might be out the window as we are missing some really critical concepts here.

The volume of the foam is absolutely and totally critical. The chemical which is trapped in the volume of the foam is NOT NOT NOT in contact with the paint. The only chemical in contact with the paint is that which is right at the interface. This is a really well appreciated concept, in fact it is the same argument which is made to suggest that the foam encapsulates and traps dirt away from the surface. Your discussion is basically saying that this argument is total nonsense. If you extend this to a logical end with a very thick foam, lets be silly and say it is a foot thick. Are you honestly telling me that you believe that the chemical which is in the foam, 1 foot away from the paint, is actually doing any cleaning?! Thus the effective concentration IS different. If half the product ends on the ground as a foam before it touches the paint, then half is wasted. Compare with a scenario where the product all contacts the paint and does some work. The effective concentration is obviously higher.

My absolutely simple argument on the foam versus pump sprayer was that the concentration in the lance bottle HAS to be higher to get the same concentration, even ignoring any air arguments. If Bilt Hamber are arguing otherwise, the person responsible needs to go back to secondary school and learn some simple logic.


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## steelghost (Aug 20, 2015)

There's two separate things here, and before we go any further, we need to separate them.

Where we are in absolute agreement is that the concentration of fluid in your foam lance bottle must be higher than in a pump sprayer, in order to take account of the fact that the lance will dilute it before it gets to the car's surface.

Where we differ is the idea that the air is in some way having any effect on the "effective concentration" of the foam. 

Let's take the hypothetical example of a foam a foot thick - sure, the foam that is out the outside of that layer isn't doing anything, and if it falls to the ground without having touched the car, it will not have done anything useful.

But consider what is happening at the actual interface of paint and liquid - the same solution at the same strength is touching the paint (and any contaminants on top of it) regardless of whether you're using a foam, or pump sprayer. Foam is not a set of little bubbles, each of which is separately contained - it's a continuous liquid, which happens to have air trapped in it by nature of the foaming agents. It's constantly moving, but at the boundary between paint and foam, the liquid is in continuous contact with the panel just as it would be if you had used a pump sprayer. 

The use of foam doesn't reduce the "effective concentration" - it just means you have to use more snowfoam solution / water to cover the car, and achieve the same actual PIR, to borrow BH's term.

Of course the thing you are looking to achieve is some degree of mechanical cleaning by the bubbles of air on the contaminants, and the dwell time of the foam meaning that the detergent has longer to work. There's no mechanical action when using a pump sprayer, and because you're typically using considerably less snow foam concentrate, some see this as a more economical way to pre-wash. I can't say how much effect the bubbles have on the cleaning effect, although it follows that if the detergent has longer to act (due to the dwell time of the foam) it will be more effective.

If you used the pump sprayer and just kept spraying the car over and over, you'd also have detergent that would run off the car without doing anything, albeit potentially with an improved end result vs a single application due to increased dwell time.


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## Cuffy (Oct 7, 2015)

Sent from my D6503 using Tapatalk


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## adjones (Apr 24, 2013)

steelghost said:


> There's two separate things here, and before we go any further, we need to separate them.
> 
> Where we are in absolute agreement is that the concentration of fluid in your foam lance bottle must be higher than in a pump sprayer, in order to take account of the fact that the lance will dilute it before it gets to the car's surface.
> 
> ...


I am afraid that my months on thermodynamics in university would lead me to disagree.

The same solution may be touching the paint, so the actual concentration is the same. But the effective concentration is different. At the paint interface, with a liquid, you have a thin film of a given concentration. Thermal velocities dictate that the chemical within this is, more or less in instantaneous contact - the chemicals zip around such that the time taken to get from one side of the film to the other is negligible. With a foam, there is an extremely thin (i.e. the bubble wall thickness) layer in contact. Since the thickness of the layer of product (i.e. foam) is large and, as you said, the product is not actually dissolved in the air, there is a huge path length for active chemical to reach the paint surface, when it is in the bulk of the foam, we are talking about thousands of times the distance (and thus time) for active chemical to move around. This means that the active chemicals at the paint interface are relatively immobile compared to when using a simple liquid. So the actual concentration is the same, but those chemicals are being used up and deactivated with time. The fact that the replenishment takes much longer with the foam means that, if you look at the real world, dynamic concentration, rather than a theoretical snapshot, that the effective concentration, with the pump sprayer is higher.

Yes, the foam lasts longer, but it is not hundreds of times or even thousands of times. So it does not account for this difference. Moreover, I have seen many foams which simple are too dilute to sufficiently reduce the surface tension and adequately wet the surface. Some people show pictures where their foam, when well broken down, is beading - this is a clear sign that the wetting is insufficient. This also doesn't consider the loss of foam which never gets near the surface and is wasted - yes you get drip off with a pump sprayer but you shouldn't be spraying so much on that you lose most of it to the ground before it does any good, that is bad technique.

So, once more, I am


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## delz0r (Mar 5, 2014)

I enjoy the science stuff. Far too many people in the detailing community take hearsay as absolute fact. I wish it was possible to buy detailing chemicals directly from chemical engineers.


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## steelghost (Aug 20, 2015)

adjones said:


> I am afraid that my months on thermodynamics in university would lead me to disagree.
> 
> The same solution may be touching the paint, so the actual concentration is the same. But the effective concentration is different. At the paint interface, with a liquid, you have a thin film of a given concentration. Thermal velocities dictate that the chemical within this is, more or less in instantaneous contact - the chemicals zip around such that the time taken to get from one side of the film to the other is negligible. With a foam, there is an extremely thin (i.e. the bubble wall thickness) layer in contact. Since the thickness of the layer of product (i.e. foam) is large and, as you said, the product is not actually dissolved in the air, there is a huge path length for active chemical to reach the paint surface, when it is in the bulk of the foam, we are talking about thousands of times the distance (and thus time) for active chemical to move around. This means that the active chemicals at the paint interface are relatively immobile compared to when using a simple liquid. So the actual concentration is the same, but those chemicals are being used up and deactivated with time. The fact that the replenishment takes much longer with the foam means that, if you look at the real world, dynamic concentration, rather than a theoretical snapshot, that the effective concentration, with the pump sprayer is higher.
> 
> ...


Now I want to know what the conclusion to the last part of your last sentence is 

I'm aware that there is always a equilibrium between depletion and migration around any reaction site - my feeling was that the foam was a sufficiently dynamic environment for detergent depletion at the paint interface to be negligible, but I admit that I have no specific data to base this supposition on (and no time to comb the literature for relevant papers, nor do sufficiently rigorous testing with pump sprayers and foams guns to reach a conclusion either way!) It feels like the 'tighter' foams would suffer more from this effect than runnier ones, though?

In any event thanks for the discussion - even if not appreciated by all the thread's participants :thumb:


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## dooka (Aug 1, 2006)

BH AF is a funny one. It is an awesome product, but you do need a lot in the foam lance to be effective, not like others where an inch or so suffices, the only downside to Auto Foam.

You want between 5-8% diluted product hitting the paint. My advice is, use it in a pump sprayer, much easier to dilute and works even better in my opinion. Certainly my go to pre-wash ..


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## 11redrex (Sep 11, 2014)

delz0r said:


> I enjoy the science stuff. Far too many people in the detailing community take hearsay as absolute fact. *I wish it was possible to buy detailing chemicals directly from chemical engineers*.


Bilt Hamber.

That is all.


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