Originally Posted by ABT B7
What do you want to know?
- Double layers are fine. I would say that when you see a limo in the daytime that you really can't see into at all it is most likely doubled up.
- Whatever the base layer or 1st layer looks like is what it will continue to look like from the outside, just darker or the traits become more prominent i.e. silvery or bluish etc. Make sure you have complimentary front/rear base layer for continuity.
- If using multiple tint products I would lay my best tint first. I.E. the ceramic extrusion or Huper.
This rear window is double tinted. Driver door is single.
Front 2 windows are single layer 20, all 5 rear windows are the same 20 layer then a 5. (This ceramic tint is super reflective, note how you cannot see through the fronts in this shot, but compare to how light they look in the above shot.)
Doubling up works best on static windows, but can work on moving ones as well. The varieties of tint come in different thicknesses so be careful when doubling up not to exceed the tolerances of free motion in the window. Cars differ on these tolerances, our Audis are pretty tight and if you go too thick you will exacerbate the scoring issue whartung is experiencing.
BTW, all brand names aside - dyed film<junk metal extrusion film<precious metal extrusion film (not common now)<modern ceramic extrusion film
All films fail over time there is no end all solution, look for an installer with a lifetime warranty. Backing glue, substrate, dye and extrusion layers are all prone to fail, it could be de-lamination, loss of adhesion, scoring, or color shift. Dyed films tend to turn purple over time, the metal extrusion films turn greenish, my jury is still out on the ceramics - I've had 'em on for 8ish months now and see no signs of degradation yet.
Also - there are a limited number of machines capable of making these products. One key in manufacturing is creating an equal layer of dye or extrusion from the beginning of the roll to the end. The tint brands have varying levels of QA. The more expensive the brand the higher the QA standards. The best guys reject more film than the bargain brands and their materials have better capabilities.