I'm planning to use the Gyeon Syncro kit, I heard the coating would last about 2 years. How do you know when it's time for a new coat? And do you just apply the new coat on the old coat or do you need to remove the old coat first?
Syncro kit is Gyeon Mohs with some other things.
Mohs is a very good ceramic and what I was going to use until I did more research and talked to the guys at Esoteric who strongly recommended the Miyabi coating for first timers.
This guy wrote a very useful thread as he had access to way more cars to coat than a typical owner would have in a lifetime. After trying all of them his best picks were either Kamikaze Miyabi with ISM or just Miyabi.
Think I`m done messing around with coatings, final thoughts...
Mohs is an excellent product, but my understanding is it is harder to work with than Miyabi as it has a much shorter flash time. With Mohs if you try to do a whole hood for example you might find that the product has already gotten tacky by the time you go to buff it off.... whereas with the Miyabi I did a whole hood, wiped it down after 5-10 minutes, and then 1-2 hours later when I was inspecting the work in better light I was still able to buff out high spots (streaks). This really saved my bacon as if the product had set up hard I would have had to remove it and reapply.
Only other advantage of Miyami is that it has a much glossier "candy" like finish where-as the Mohs coating is a bit warmer. Kind of comes down to your personal preference and the author of the thread I linked comments that some products are better on dark finishes than light finishes.
Any ceramic coating will eventually wear out. You will probably know when it is wearing out as the shine will be gone and it won't be beading as well. If maintained well (washed properly and correct top coat applied every 1-2 months) you should get 18-24 months out of most consumer grade coatings.
When it is time to apply you want to remove what's left of the old coating with either a chemical removal spray (available for some finishes) or you will have to polish the coat off so new coat will stick to clear coat. This is needed for removal of Miyabi and is probably the only real drawback I can see to it.
Probably when my coating starts looking worn I will just pay a professional detailer to polish off the old coating, and then I will do application of a new coating myself. If someone else did that part and I did the coating in good weather (warmer temps, lots of light) it really shouldn't take more than a few hours to do 2 coats of the Miyami and one coat of the ISM, I believe that is supposed to be good for about 2-3 years.
Good luck.