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Originally Posted by HarryM1BYT

I just had it in mind that the suggested German solution was just too expensive for two small aerosol cans. I take some serious persuading that it really contained something different.

It is nothing really different. With a basic compressor or air brush you could do the same thing (maybe even better), providing you make allowances for the expansion and contraction on the poly due to heat variations.

Like you, I believe the kit is overpriced, but it does have shiny things on the can, so it MUST be the best HERE is just one example, and even has Spraymax(­™?) technology, 400ml can for similar monies as the two small cans. With a 500ml primer HERE.(I have used this aersol system before, and it is not too bad to use for a rattle can. with adjustable fan).

I wonder if the 2k type lacquers may be a bit hard, and possibly chip through use? A cheaper acrylic on a properly prepared headlight may be more long lasting



The cling film was just something read about, to throw into the mix - really I wondered if anyone else had heard of such a suggestion.

I knew what you were suggesting, but I still imagine that it was some kind of vinyl system that has been on the market for a while now.


One difference between attempt 1 and 2 was that I washed the lens in soapy water and sun dried it, after I had prepared it for spraying in 1. For 2 I gave it a final wipe with isopropyl. Despite that....


After getting it prepared in 1 - I could see like a slight feathering marking in the lens, similar to the marks in my own MII lenses. I assumed it was a peculiarity of the lens or marks on the inside of the lenses. The marks became even more obvious after I had sprayed the test lens, plus the misted, cracked lacquer surface.


With my more aggressive 'attempt 2' using 100 grit, those feathering marks had disappeared - so it was obviously original lens coating still in place.

There are cheap polishing kits available, with a drill adapter, for less than £10. (they are just various descending grades of wet and dry paper, a drill adapter and polish, so you could already have the components in a shed). EXAMPLE KIT


I have done my MKII lenses a few times (without any lacquer), the first time sanded down, then polished up, then they have just needed the regular annual re-polishing up since then. Not knowing how thick the polycarbonate might be - I've been a bit wary of being too aggressive when sanding it back, but from my experiment, it seems to be essential it be done quite aggressively.

The kit I used, similar to the one I linked above, has 80 grade wet and dry, and used it on a gouged and cloudy Passat headlight. Once you get up to around 2000 grit, you start to see it becoming clear. I was even tempted to leave it at 3200 grit, as they were nearly perfect at that stage! But the polish made them sparkle. There is a UV polish to add, but it is a similar product to RainX, in that it washes off within a few weeks.


Another thought has occurred to me, because the old lacquer is so difficult to remove - might it actually be the original lacquer coating which deteriorates, rather than the actual surface of polycarbonate of the lens?

It is the old lacquer that breaks down, if you look at some 'failed' lights whilst you are out and about, you will see that feathering, and yellowing around the edges of it. Although in saying that, the polycarbonate will, I have no doubt, break down once exposed to the elements and driving in traffic.



When rubbing it down, try to use a flexible pad behind the sanding media, and not use fingers. As you lean into the paper to rub it down, you could rub fine grooves into the surface of the lens/remaining lacquer. Maybe light rubbing down the fresh lacquer with 3200 wet wet and dry, between coats will allow a decent quality build.