[Niall McAllister]

hi all,
I know this topic has been covered in the past, but, can't find the answer i need, so,
I've been asked to quote a big new house which is fitted with Pilkington Activ glass ( to get round the scottish laws about accessability to windows). what are the problems using trad on this glass and are there any pointers to avoid the problems.
also, while I don't use wfp, how does this fair with activ glass?
thanks
niall

[Roger Slater]

I use wfp on this so called self cleaning glass with no problems, this is a very clever gimmick by pilkington its suppose to use the suns rays to stop the glass from becoming dirty, what a load of cods wallop. I have custys i do 6 weekly with self cleaning glass and its really dirty when i goto clean them, and also how does self cleaning glass clean bird poop off?

Never tried trad on this type of glass so don't know about that.

[jakeandmia]

I have a couple of custys with this glass and find wfp is a better way to clean,when i did it trad the blade never seemed to slide as good as it did on normal glass

[DaveG]

dont quote me but i thought self cleaning glass was coated with something that stops stuff sticking to it and when it rains it "cleans" it...

But in the summer when people want their windows nice and clean............it dont rain!!

apart from the last 2 summers lol

[Tim82]

Yeah I did a self cleaning glass clean, trad, and the window was sticky and the squeegee seemed to stick to the glass, didnt get a good finish.

[michael papworth]

dont quote me but i thought self cleaning glass was coated with something that stops stuff sticking to it and when it rains it "cleans" it...

But in the summer when people want their windows nice and clean............it dont rain!!

apart from the last 2 summers lol

Yes, you're very close, but not quite right. There's a little bit you've missed out.

The glass is coated with one or more thin films of titanium dioxide (TiO₂). This chemical has TWO amazing properties.

The first is that it can oxidise organic matter.

So what does that mean? Oxidise, in this context, means low-temperature chemical burning. Organic materials mean natural deposits like bird poo and films left by plant materials - essential oils and such. This is the basic muck that we find on windows, plus dust and traffic film.

The second property is that it is super-hydrophilic. That means that it is completely wetted by water and a film of water on the surface is very thin. The contact angle is almost zero degrees. Because the film is so thin, it evaporates very quickly.

We're all familiar with hydrophilic glass and we notice that it dries from the top!

In order for the TiO₂ to work, it needs plenty of sunlight. It then oxidises the "muck" on the windows and turns it to dust. This is then just washed away by the rain.

For this self-cleaning glass to work well you need (i) lots of strong sunlight and (ii) torrential rain. Fine if you live in Florida, not too good if you live anywhere in the UK.

The film is made up of particles in the 10nm to 100nm range. (nm = nanometers). If I understand things correctly, the glass can have up to 10 films, one on top of another.

The thickness of the film is therfore a few microns thick. Personally, I wouldn't take a squeegee anywhere near it for fear of scratching. The TiO₂ itself is very tough (being a ceramic material) but being so thin I imagine that it would scratch quite easily.

PS:
1 mm = 1000 microns
1 micron = 1000 nanometers.

You can see micron sized things under a microscope. Nanometer sized things need an electron microscope to see them.

Hope this helps clarify things a little.

Summary 1:

It's a 2-stage process.

Stage 1 - Bright sunlight oxidises (=burns off) organic materials.

Stage 2 - Torrential rain washes the surface clean.

(If you understand that much, you understand more than the people who sell the stuff!)

* Not enough sunlight? Won't work.

* Light rain or drizzle? Won't work.

Live in UK? It won't work - since we don't get enough sunlight and the rain we get is usually quite light and prolonged.

Summary 2:

* Using a squeegee could scratch the glass if there's any dust left. These scratches CANNOT be polished out as polishing would take off the  TiO₂ film.

* Other have noted that the blade doesn't slide well - and you don't want to be using detergents on this glass anyway.

* WFP is ideal since it agitates the dirt off the glass and simulates a good downpour to rinse the stuff away.

[DaveG]

dont quote me but i thought self cleaning glass was coated with something that stops stuff sticking to it and when it rains it "cleans" it...

But in the summer when people want their windows nice and clean............it dont rain!!

apart from the last 2 summers lol

Yes, you're very close, but not quite right. There's a little bit you've missed out.

The glass is coated with one or more thin films of titanium dioxide (TiO₂). This chemical has TWO amazing properties.

The first is that it can oxidise organic matter.

So what does that mean? Oxidise, in this context, means low-temperature chemical burning. Organic materials mean natural deposits like bird poo and films left by plant materials - essential oils and such. This is the basic muck that we find on windows, plus dust and traffic film.

The second property is that it is super-hydrophilic. That means that it is completely wetted by water and a film of water on the surface is very thin. The contact angle is almost zero degrees. Because the film is so thin, it evaporates very quickly.

We're all familiar with hydrophilic glass and we notice that it dries from the top!

In order for the TiO₂ to work, it needs plenty of sunlight. It then oxidises the "muck" on the windows and turns it to dust. This is then just washed away by the rain.

For this self-cleaning glass to work well you need (i) lots of strong sunlight and (ii) torrential rain. Fine if you live in Florida, not too good if you live anywhere in the UK.

The film is made up of particles in the 10nm to 100nm range. (nm = nanometers). If I understand things correctly, the glass can have up to 10 films, one on top of another.

The thickness of the film is therfore a few microns thick. Personally, I wouldn't take a squeegee anywhere near it for fear of scratching. The TiO₂ itself is very tough (being a ceramic material) but being so thin I imagine that it would scratch quite easily.

PS:
1 mm = 1000 microns
1 micron = 1000 nanometers.

You can see micron sized things under a microscope. Nanometer sized things need an electron microscope to see them.

Hope this helps clarify things a little.

Summary 1:

It's a 2-stage process.

Stage 1 - Bright sunlight oxidises (=burns off) organic materials.

Stage 2 - Torrential rain washes the surface clean.

(If you understand that much, you understand more than the people who sell the stuff!)

* Not enough sunlight? Won't work.

* Light rain or drizzle? Won't work.

Live in UK? It won't work - since we don't get enough sunlight and the rain we get is usually quite light and prolonged.

Summary 2:

* Using a squeegee could scratch the glass if there's any dust left. These scratches CANNOT be polished out as polishing would take off the  TiO₂ film.

* Other have noted that the blade doesn't slide well - and you don't want to be using detergents on this glass anyway.

* WFP is ideal since it agitates the dirt off the glass and simulates a good downpour to rinse the stuff away.

Thanks Wally thats made things a lot clearer!!!! LOL

[Captain Scarlet]

Well as I mentioned in another post as it happens, I clean windows for somebody who was one of the big wigs at Pilkington ( he still holds shares in the company ) anyway his whole mansion is Pilkington activ...suprise suprise!!! Anyway he was skeptical about wfp, so he phone up Pilkington ( being a shareholder...talked to one of the top guys ) and he said only a cloth can be used. Well he le me use my wfp on his whole house....and he couldnt be any happier. So there we go, even Pilkington blokes use wfp!!! ha ha

[MJH]

dont quote me but i thought self cleaning glass was coated with something that stops stuff sticking to it and when it rains it "cleans" it...

But in the summer when people want their windows nice and clean............it dont rain!!

apart from the last 2 summers lol

Yes, you're very close, but not quite right. There's a little bit you've missed out.

The glass is coated with one or more thin films of titanium dioxide (TiO₂). This chemical has TWO amazing properties.

The first is that it can oxidise organic matter.

So what does that mean? Oxidise, in this context, means low-temperature chemical burning. Organic materials mean natural deposits like bird poo and films left by plant materials - essential oils and such. This is the basic muck that we find on windows, plus dust and traffic film.

The second property is that it is super-hydrophilic. That means that it is completely wetted by water and a film of water on the surface is very thin. The contact angle is almost zero degrees. Because the film is so thin, it evaporates very quickly.

We're all familiar with hydrophilic glass and we notice that it dries from the top!

In order for the TiO₂ to work, it needs plenty of sunlight. It then oxidises the "muck" on the windows and turns it to dust. This is then just washed away by the rain.

For this self-cleaning glass to work well you need (i) lots of strong sunlight and (ii) torrential rain. Fine if you live in Florida, not too good if you live anywhere in the UK.

The film is made up of particles in the 10nm to 100nm range. (nm = nanometers). If I understand things correctly, the glass can have up to 10 films, one on top of another.

The thickness of the film is therfore a few microns thick. Personally, I wouldn't take a squeegee anywhere near it for fear of scratching. The TiO₂ itself is very tough (being a ceramic material) but being so thin I imagine that it would scratch quite easily.

PS:
1 mm = 1000 microns
1 micron = 1000 nanometers.

You can see micron sized things under a microscope. Nanometer sized things need an electron microscope to see them.

Hope this helps clarify things a little.

Summary 1:

It's a 2-stage process.

Stage 1 - Bright sunlight oxidises (=burns off) organic materials.

Stage 2 - Torrential rain washes the surface clean.

(If you understand that much, you understand more than the people who sell the stuff!)

* Not enough sunlight? Won't work.

* Light rain or drizzle? Won't work.

Live in UK? It won't work - since we don't get enough sunlight and the rain we get is usually quite light and prolonged.

Summary 2:

* Using a squeegee could scratch the glass if there's any dust left. These scratches CANNOT be polished out as polishing would take off the  TiO₂ film.

* Other have noted that the blade doesn't slide well - and you don't want to be using detergents on this glass anyway.

* WFP is ideal since it agitates the dirt off the glass and simulates a good downpour to rinse the stuff away.

Very interesting post!!