pH of Some Common Products Unveiled

Reading this thread reminds me of my failure to pay attention to chemistry lessons at school. So far, the only bit I understood was the mention of residue which I do think needs more discussions, plus the role of dwell time
 
Lowejackson said:
Reading this thread reminds me of my failure to pay attention to chemistry lessons at school. So far, the only bit I understood was the mention of residue which I do think needs more discussions, plus the role of dwell time
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Residues are something that are everywhere and they are things which are often very hard to eliminate or, at the least, negate in effect. Think of a traditional cleaner - it will tend to consist of several groups of ingredients. You often have something to give alkalinity (this is the dominant class), something to deal with a small amount of water issue (like hardness), you might have a bit of solvent to boost cleaning and you will almost certainly have surfactants. The first two will typically be very water soluble and will be easy to rinse. The solvents will often be the same and will often be volatile. As such, these are pretty easily removed with a rinse. Surfactants are another matter entirely. Surfactants are almost never volatile - they do not evaporate away. In fact, the more you let them dry out, the harder they become to dissolve/rinse. Then we have the way in which they operate - they actually 'bond' to oils and dirt. This means that a residue is going to be inherently sticky (much of the time). In addition, surfactants also 'bond' with water - so a residue is generally going to be sticky to water (which is why dawn and similar can confuse people into thinking their LSP is stripped).

Dwell time - think of chemicals as little molecular machines. You put them onto the dirt and they buzz around cleaning. Like a machine, it takes time for them to actually work their way through the dirt. As such, you need an adequate contact time to do the cleaning. Of course, you can often get away with less time if you are going to be scrubbing/wiping/doing mechanical work.
 
Lowejackson said:
Reading this thread reminds me of my failure to pay attention to chemistry lessons at school. So far, the only bit I understood was the mention of residue which I do think needs more discussions, plus the role of dwell time
Click to expand...

I know the feeling. I'm seem to always think, "Boy, I sure hope there won't be a quiz at the end."

in all seriousness, I really do enjoy these discussions greatly. PiPUK does a great job of getting things explained so we can all understand. Good job Sir!

Bill
 
PiPUK said:
Dwell time - think of chemicals as little molecular machines. You put them onto the dirt and they buzz around cleaning. Like a machine, it takes time for them to actually work their way through the dirt. As such, you need an adequate contact time to do the cleaning. Of course, you can often get away with less time if you are going to be scrubbing/wiping/doing mechanical work.
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Doesn't this then support using a foam cannon or foam gun where the soap/foam clings to the paint to help reduce the amount of scrubbing?
 
I always look forward to your posts PiPUK

What does PiPUK mean?
 
Bunky said:
Doesn't this then support using a foam cannon or foam gun where the soap/foam clings to the paint to help reduce the amount of scrubbing?
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That is the idea behind snowfoam - you get longer contact, the dirt is softer and can be more easily removed with a pressure washer. The original idea was to get rid of that dirt before you touch the surface, I realise that many use it without the pressure washer and I do think that this negates a lot of the theoretical benefit. Snowfoam also tends to be very mild because the foam is much more dilute than you would realise - it may be 100:1 going through a lance, but that is the liquid. In reality, only a small part is in contact with the surface because much is trapped in the foam (think of there being a dilution in water AND air). That is also one of the reasons that an excessively stable foam is bad - the foam should break down and replenish the surface with fresh product. If the foam is really stable, most of the product resides in the foam and never gets anywhere near the surface (so it is totally wasted when you then rinse it down the drain).
 
PiPUK said:
That is the idea behind snowfoam - you get longer contact, the dirt is softer and can be more easily removed with a pressure washer. The original idea was to get rid of that dirt before you touch the surface, I realise that many use it without the pressure washer and I do think that this negates a lot of the theoretical benefit. Snowfoam also tends to be very mild because the foam is much more dilute than you would realise - it may be 100:1 going through a lance, but that is the liquid. In reality, only a small part is in contact with the surface because much is trapped in the foam (think of there being a dilution in water AND air). That is also one of the reasons that an excessively stable foam is bad - the foam should break down and replenish the surface with fresh product. If the foam is really stable, most of the product resides in the foam and never gets anywhere near the surface (so it is totally wasted when you then rinse it down the drain).
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How do you tell if a foam is stable?
 
ZL1 Mark said:
How do you tell if a foam is stable?
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Spray it on and see if it sticks like shaving foam (and clogs the drains after rinsed!) or whether it breaks down and flows off over a few minutes. It is a fine balance, in my view it should go on pretty thick but should star running off within a couple of minutes, give it 10 mins and it should mostly be gone. Some products out there fail because they are obsessed with the foam lasting absolutely ages, others fail because they run off too fast.
 
PiPUK said:
Spray it on and see if it sticks like shaving foam (and clogs the drains after rinsed!) or whether it breaks down and flows off over a few minutes. It is a fine balance, in my view it should go on pretty thick but should star running off within a couple of minutes, give it 10 mins and it should mostly be gone. Some products out there fail because they are obsessed with the foam lasting absolutely ages, others fail because they run off too fast.
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Any recommendations?
 
PiPUK said:
Spray it on and see if it sticks like shaving foam (and clogs the drains after rinsed!) or whether it breaks down and flows off over a few minutes. It is a fine balance, in my view it should go on pretty thick but should star running off within a couple of minutes, give it 10 mins and it should mostly be gone. Some products out there fail because they are obsessed with the foam lasting absolutely ages, others fail because they run off too fast.
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Great information from an angle I had not considered previously
 
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