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Old 19th June 2011, 01:10   #1516
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Default Re: Front windscreen sunfilm?

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Originally Posted by Ragul View Post
If one Hanky takes 30 mins to dry in the sun, how much time will it take to dry 10 Hankies?

I thought this case applies here... guess not! The effect should be cumulative as you put it.

--Ragul

Well 10 hankies in sun on a monsoon day - will not dry the whole day.

On the same day the one hanky dried in 30min (weather humidity etc. same) - you put the 10hankies one on top of the other - the middle ones will take several hours to dry.


Plus you applied the funda to the wrong problem


Quote:
Originally Posted by Ragul View Post
Is it really possible? Can the second layer be peeled off safely leaving the original film intact - to "con" an RTO inspector?

Will adding another 70% film on top of existing 70% film reduce the VLT further or will it remain at 70%? By how much?

Put differently - a 60% film on top a 70% film will result in a VLT of ____? (fill in the blanks) (10 marks)

--Ragul


You get a 0



PS: no offence buddy - just having fun.




Coming to one CR70 on top of another - even a single CR70 rejects almost 100% of IR (some places the claim is 99%, other places it is 97%) - so IR rejection and UV rejection are both moot for this case - even the first film would get rid of practically everything.

In visible things are tricky - the first film reflects and absorbs 30% and lets 70% through. The second film will reflect and absorbed 30% of the first 70% (i.e. 21% of the total input) and let the rest (i.e. 49% of the total input) through.

So prima facie 49% of the total input is let in by the second film - but wait: of the 21% that the second film reflected, some will be reflected back now by the first film towards inside of the car (because as far as the outer film is concerned, this is coming from inside the car) !

If only reflection and no absorption was going on, the multiple reflections will cause overall transmittance to go up by roughly 5.5%

i.e. overall transmittance will be close to 55% (not 49%) if only reflection was going one. If only absorption was going on (unlikely - if the film absorbs the light rather than reflecting it - it still ends up heating your car) then it'll be exactly 49%. For most other cases it'll be in between.


I just wasted some minutes writing it, and you have wasted some minutes reading it (unless you enjoy technical nuances) because 55% and 49% are virtually the same.


Also things like interference, angle of incidence etc. will make this more fun - that discussion belongs in one one of the "Technical Stuff" threads.





By the way, why would you want to reduce the visibility on the front screen? Please keep in mind that CR70 specs are 69% transmittance for light that comes perpendicular (90 degrees) to the film. For light that comes oblique (and unless you are driving a bus or a truck with vertical windscreen - all light that you are using to scna the road ahead is coming oblique) the transmittance is lesser for all 3M films - e.g. CR70 spec says 59% for a 60degree angle, and given the actual angles of many passenger car windscreens (all are smaller than 45degrees usually to horizontal) the transmittance will be even smaller.

In such a case you'll be losing way more than you realise, e.g. 59% one film = 36% two films. 50% one film = 25% two films.

I believe that this will become very dangerous for night driving.



sometime ago Mustang.101 posted about some film that behaves like a photo-chromatic glass - it gets darker when light is strong, and clears up at night. I guess that will be the best in all conditions.

Last edited by vina : 19th June 2011 at 01:22.
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Old 19th June 2011, 01:39   #1517
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Default Re: Front windscreen sunfilm?

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Originally Posted by ST7677 View Post
Indian RTO rules are archaic.
If I remember it correctly, probably the Inspector is correct. From what I remember the rule says that the front windshield should not have any film AND the front glass visibility should be at least 70% and side glass 50%.

Here's a link:

http://morth.nic.in/writereaddata/su...2608339380.pdf


Front and rear - 70%, sides 50%

From the reading it says "glass" it doesn't say anything about film. But "will be maintained in such condition" - this should give you leeway to include film+glass as glass. In fact the "explanation" they have make it mandatory to have a safety film (whether explicit or embedded in the windshield) of plastic on the windshield.

This RTO guy was just trying to show off - ask him to book a case.
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Old 19th June 2011, 12:44   #1518
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Default Re: Front windscreen sunfilm?

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Originally Posted by backrub View Post
swiftnfurious, I am also thinking about trying Sachin's Autoshop, is there anyone who has got the front windscreen installation done from there ?
ME ! I am quite happy with their installation. No issues as such. I got my side & rear windshields also done from there, am quite happy with the installation. The owners there are very customer centric and helpful. My friend also got his front windshield installation done twice for his cars and is also very happy.

Quote:
Originally Posted by backrub View Post
Any ideas on the prices of front windshield film from Vkool top of the range like CR70 of 3M.
I remember some accessories shop quoting a 12K or so for a swift for V-Kool front windshield. I am not able to recollect it correctly though now.

Edit:: In one of the shops, they actually have a small demo where they have a hexagonal box with a 100W bulb in the center. In each wall [glass / plastic], he has a different brand of sun film stuck and once he lights up the bulb, it starts radiating heat in less than a min. He actually has 3M and V Kool back to back and the difference is TOO BIG to ignore! Though V Kool costs a bomb, its equally impressive.

Last edited by swiftnfurious : 19th June 2011 at 12:51.
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Old 19th June 2011, 12:49   #1519
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Default Re: Front windscreen sunfilm?

I got my windscreen sunfilm coating done from Vkool. They give a big discount to TBHP members.

I have driven in pouring rain and in the dark on highways and dirt tracks. No issues - but then again, the Fortuner's highbeam is pretty powerful.

It makes sense to get the highest quality sufilm for the windscreen. And getting it done from the company outlet if possible, because of warranty honour etc.

Overall, the 30% reduced visibility is worth it for the daytime heat + radiation reduction. We traveled in 40-50 degree centigrade temperature during our early June MP trip, and within the car we didn't feel the heat.
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Old 19th June 2011, 13:10   #1520
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Default Re: Front windscreen sunfilm?

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Originally Posted by nilanjanray View Post
I got my windscreen sunfilm coating done from Vkool. They give a big discount to TBHP members.

I have driven in pouring rain and in the dark on highways and dirt tracks. No issues - but then again, the Fortuner's highbeam is pretty powerful.

It makes sense to get the highest quality sufilm for the windscreen. And getting it done from the company outlet if possible, because of warranty honour etc.

Overall, the 30% reduced visibility is worth it for the daytime heat + radiation reduction. We traveled in 40-50 degree centigrade temperature during our early June MP trip, and within the car we didn't feel the heat.
How much did it cost you and which VKOOL outlet gave you discounts for TBHP ?Also please share the before and after discount cost.Thanks
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Old 27th June 2011, 18:38   #1521
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Default Re: Front windscreen sunfilm?

Quote:
Originally Posted by vina View Post
Here's a link:

http://morth.nic.in/writereaddata/su...2608339380.pdf


Front and rear - 70%, sides 50%

From the reading it says "glass" it doesn't say anything about film. But "will be maintained in such condition" - this should give you leeway to include film+glass as glass. In fact the "explanation" they have make it mandatory to have a safety film (whether explicit or embedded in the windshield) of plastic on the windshield.

This RTO guy was just trying to show off - ask him to book a case.

I don't think this in conclusive. This is more about manufacturing specifications. Do note that by default glass does not have 100% visibility. A lamented glass has even lower visibility. This just specifies that the front glass should be lamented and have 70% visibility (manufacturing specification).

There is a separate section which covers tinting regulations please provide link to that.

Also, do note that, if you apply a 70% film to say a 90% glass, then net visibility is only 63%.
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Old 27th June 2011, 19:37   #1522
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Default Re: Front windscreen sunfilm?

Quote:
Originally Posted by ST7677 View Post
I don't think this in conclusive. This is more about manufacturing specifications. Do note that by default glass does not have 100% visibility. A lamented glass has even lower visibility. This just specifies that the front glass should be lamented and have 70% visibility (manufacturing specification).

There is a separate section which covers tinting regulations please provide link to that.

Also, do note that, if you apply a 70% film to say a 90% glass, then net visibility is only 63%.

All the films in the market give their transparency with glass . e.g. CR70 film lets 69% light though and CR50 lets 49% through when used with glass.

even other specs (IR, UV etc.) are with glass.

Last edited by vina : 27th June 2011 at 19:50.
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Old 28th June 2011, 13:00   #1523
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Default Re: Front windscreen sunfilm?

Quote:
Originally Posted by vina View Post
All the films in the market give their transparency with glass . e.g. CR70 film lets 69% light though and CR50 lets 49% through when used with glass.

even other specs (IR, UV etc.) are with glass.
Yes agreed, but it is with basic glass.
Most cars today have more than basic glass (lower than standard visibility). I know Honda cars comes with Green tint from factory which do block IR/UV to some extent.

Anyway, the point is what does the law book say about tinting, if you can share that section, that will be helpful to all.
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Old 28th June 2011, 13:15   #1524
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Default Re: Front windscreen sunfilm?

Quote:
Originally Posted by ST7677 View Post
Yes agreed, but it is with basic glass.
Most cars today have more than basic glass (lower than standard visibility). I know Honda cars comes with Green tint from factory which do block IR/UV to some extent.

Anyway, the point is what does the law book say about tinting, if you can share that section, that will be helpful to all.

Even sheet glass used for windows has a green tint if you look on the sides. Also, 3M (and Llumar I believe) does its testing with the relevant glass (i.e. automotive grade) as defined in US standards (I think ASTM)

Law says:

front and rear must have over 70% visible light transmission, all other glasses over 50%.

On whether to use film at all it seems to be ambiguous, but in Delhi, traffic police allows the film as long as the above standards are met (they check with equipment to measure light transmission).

In most other cities the cops don't care a damn.

Last edited by vina : 28th June 2011 at 13:17.
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Old 28th June 2011, 22:25   #1525
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Default Re: Front windscreen sunfilm?

Which is the best place to get Windscreen film fixed on my new Innova in Hyderabad ? I am looking at LLumar or 3M, because VKool seems too expensive.

Any idea of how much this should cost me? I presume I can legally go for darker (50% VLT) film on the windows and rear - how much can I expect to pay to get the film done an Innova?

I am getting a Silver Innova - any recommended shades of film that look best on this colour?

Thanks for your advice.
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Old 28th June 2011, 23:09   #1526
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Default Re: Front windscreen sunfilm?

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Originally Posted by vartakavi View Post
Which is the best place to get Windscreen film fixed on my new Innova in Hyderabad ? I am looking at LLumar or 3M, because VKool seems too expensive.

Any idea of how much this should cost me? I presume I can legally go for darker (50% VLT) film on the windows and rear - how much can I expect to pay to get the film done an Innova?

I am getting a Silver Innova - any recommended shades of film that look best on this colour?

Thanks for your advice.

Legally - front and rear 70%, other windows 50%

In hyderabad - nobody gives a damn about the law.

Let me know if you find a good place to get the work done - I need it done too.
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Old 28th June 2011, 23:48   #1527
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Default Re: Front windscreen sunfilm?

Quote:
Originally Posted by vina View Post
Legally - front and rear 70%, other windows 50%

In hyderabad - nobody gives a damn about the law.

Let me know if you find a good place to get the work done - I need it done too.
I got 3M CR70 fitted for my car at IndianDecars, Banjara hills and very happy with the installation and the results. The installation guy is very professional.
If I remember correctly, it costed me around 5.5K approx. As the windscreen for Jazz is huge, it might have costed more.
Would certainly recommend. PM me if you need the contact details. It is also listed in TBHP.

Last edited by adimicra : 28th June 2011 at 23:52.
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Old 29th June 2011, 02:03   #1528
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Default Re: Front windscreen sunfilm?

Quote:
Originally Posted by vartakavi View Post
Which is the best place to get Windscreen film fixed on my new Innova in Hyderabad ? I am looking at LLumar or 3M, because VKool seems too expensive.

Any idea of how much this should cost me? I presume I can legally go for darker (50% VLT) film on the windows and rear - how much can I expect to pay to get the film done an Innova?

I am getting a Silver Innova - any recommended shades of film that look best on this colour?

Thanks for your advice.
Barring the first two cars that we owned, we have not installed film in the last three cars (Baleno, Santro and Innova) that we purchased. Especially with Innova, there are many reasons - visibility is excellent w/o the film and it really matters in the night when the multiple blind spots of Innova with poor visibility from the sides can wreck havoc. In the day, you will not find the AC insufficient even without it.

Getting some sun is good for the bones and joints in the old age. Finally an evening ride in the car, especially on the airport expressway looks a surreal experience, what with king size windows in the Innova and a beautiful setting sun. Of course the privacy is a bit less but I am fine with that!
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Old 29th June 2011, 13:22   #1529
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Default Re: Front windscreen sunfilm?

Quote:
Originally Posted by vartakavi View Post
Which is the best place to get Windscreen film fixed on my new Innova in Hyderabad ? I am looking at LLumar or 3M, because VKool seems too expensive.
Quote:
Originally Posted by vina View Post
Let me know if you find a good place to get the work done - I need it done too.
I have got it done for my scorpio at Pit-stop Somajiguda.

Reliance Autozone also provdies geniune stuff. Both the places have good installers

cheers
NH
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Old 29th June 2011, 16:41   #1530
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Default Re: Front windscreen sunfilm?

Has anybody fit the front windshield sunfilm on their Tata Nano in Bangalore? I checked with the authorized dealer and they do not have it.

Any recommendations on brands / installers?
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