Brother sealant is a temporary solution, I also been working in Toyota Capital Islamabad for 5 years. Automobile companies all over the world go for this process;
1.Red Oxide
2.Under coat,
3.Aster
4.Paint layer 1
5.Paint layer 2 and some automobile companies go for 3-5 coats.
6. Hardner
7. Lyker for shine.
They dont apply sealant because Hardner has 50% sealant.
so what happens is that Lyker is a clear coat tin layer and gets damaged with UV light as weather in Pakistan and mostly Asian countries, it also get damaged when you rub a dry cloth on the car body result in scratches in tin layer of lyker. Paint is under hardner is it is never damaged.
Sealant helps to add a extra coat on to lyker and sealant is a hard layer and is not eaily damaged with rubbing cloth and UV rays.
Regarding your question about compound we at Toyota use this compound for new and accident cars, more the light compound more has absorption in hardner.
for more information and querries you can visit our workshop.
a good sealant last for 3 years if properly applied.
