Well, I have concluded my original spar urethane longevity test with the two year update. Headlight Restoration-new UV sealant idea
And now I am ready to try the unpolished version, and see how long it lasts, but I am testing it head to head against Opti Coat 2.0 to see which lasts the longest. The test car is the same car in my original thread, a 1998 Mercury Grand Marquis that does not get too much washes or wax jobs, plus it sits outside 24/7. The passengers side light will be treated with the Minwax spar urethane(unpolished version) and the drivers side with the Opti coat 2.0.
Minwax Spar Urethane/mineral spirits VS Opti-coat 2.0
Here is my step by step process for this test.
Both lights were washed, and then masked off with painters tape to prevent scratching paint and chrome trim.
Here is my sandpaper of choice, 1500, 2000 and 3000. Anything more aggressive and it would have been overkill, the old spar urethane treatment is very soft and thin, so it was very easy to remove.
I use this meguiars sanding backing pad to aid in the wet sanding process.
I soak all the sand paper in a bucket of water with grit guard. My chosen soap for lubricant is Meguiars hyper wash.
I soak the light down by spraying water before wet sanding.
And begin sanding, starting with 1500, 2000 and finish with 3000.
Close up picture of sanding "slurry" remnants of 2 year old spar urethane.
Now here is where the whole process changes, the opti coat side needs polished before application and the spar urethane does not and is ready for application now. Here is my polisher of choice for the opti coat side, my dewalt rotary with orange and black pad.
The compound and polish I used for the opti coat side is Megs M105 and M205.
And here is the drivers side light after polishing and ready for Opti coat 2.0. But first it needs a wipe down with IPA to remove all polishing oils, and insure a proper bond.
Here is the finished side of the Opti coated headlight. I applied it with the provided sponge, and basically followed the instruction on the syringe.
Here is my spar urethane supplies, I use a measuring spoon to make sure I get the 50/50 spar urethane/mineral spirits correctly mixed. I use a plastic wax free cup, and use a pop sicle stick to mix everything up.
Here is what the mixture looks like.
And here is my applicator, a blue scotts shop rag folded up.
I wipe the mixture on side to side with the spar urethane. Remember, I did not polish these lights before applying this sealant as it is not necessary and hopefully provides a better "bite" for the sealant and maybe lasts longer as well.
And here is the finished Spar urethane side.
Both lenses look good after the process, but I must say that in my opinion, the spar urethane side looks slightly better than the opti coat side in person. But the real test will be which will last longer. I will keep up on this, and try and take pictures every 3 months and post here, if anyone is still interested. Please keep giving me suggestions on this process, as I am still learning myself. And I encourage other members to do tests like this to get more comparison and get different climates factored in as well.