Headlight sealant: spar urethane vs. opti coat 2.0

[Part-timer]

I used Hotrod's method and the result is fantastic. The lights are looking brand new. That was a week ago. It rained the last couple of days and finally it stop raining today. I inspected the light and saw water mark all over the lens. What should i do? It's looking so bad that i'm tempted to redo the whole thing again. suggestion please

How long was it after applying the spar mix, that the lenses got rained on?

[GalKonz]

I used Hotrod's method and the result is fantastic. The lights are looking brand new. That was a week ago. It rained the last couple of days and finally it stop raining today. I inspected the light and saw water mark all over the lens. What should i do? It's looking so bad that i'm tempted to redo the whole thing again. suggestion please

You gotta renew the seal 'cause it's leaking water inside the lights.

Condensation on headlights is a common problem, and it is mostly fixed by taking lights out of the car, then take apart the polycarbonate cover and the base of the light, cleaning, eliminating dried out silicone, and applying new silicone. IMO

Or maybe you didn't prepared thoroughly the lens before applying the spar urethane mix... (?). But i vote for inner condensation issues.

[GP49]

I used Hotrod's method and the result is fantastic. The lights are looking brand new. That was a week ago. It rained the last couple of days and finally it stop raining today. I inspected the light and saw water mark all over the lens. What should i do? It's looking so bad that i'm tempted to redo the whole thing again. suggestion please

The spar urethane WILL absorb a small amount of water, which then has to evaporate out. I've seen it take several hours for the watermarks to disappear. Update us...once the headlights were totally dry...a day or so...how did they look?

If this is happening, do not wipe the headlights until completely dried through, as the surface of the urethane feels a bit softer when damp.

[ray6]

Wet the surface with water. If the spots disappear, it's on the outside. If they don't, it's on the inside. I don't use the spar method, but I'm familiar with solvent based polyurothanes of which Minwax is one type. If water got under the coating or the coating appears to be defective, remove it with mineral spirits if it hasn't hardened yet (takes about 2 weeks to fully cure). If it's hard, sand it off but don't use anything rougher than 500 to 1000 grit. If you prepared the surface well the first time, you don't want to go backwards.

Another possibility is that the spar didn't stick to the polycarbonate. Things to check:

Did you use any compound or polish after initial sanding? Any wax will contaminate.

If you used a foam applicator was it latex free?

Did you scrub the light well with pure alcohol (preferred) or odorless mineral spirits.

Did you mix your spar/ms in a wax coated cup?

Any chance of contamination from your applicator?

If rain/high humidity is an issue, apply low heat from a hair dryer after coating to get it cured faster.

ray6

[ray6]

[QUOTE=mstapes;673857]Sorry if this has been covered already, but I have some Ace Spar Varnish in the house will this work as well?

The label seems contradictory though:

Solvent Based Spar Varnish Clear Gloss
-for all wood surfaces
-rich amber finish
-interior or exterior
-Long lasting UV protection
-Water resistant

They mean rich amber when applied to wood. The thickness on headlights is too thin to really see the amber finish. It will probably appear amber in the can.
ray

[GP49]

If rain/high humidity is an issue, apply low heat from a hair dryer after coating to get it cured faster.

Turning the headlights ON, high beam, helps also, by warming them up from the inside.

[HotRod]

11 month update on car #1 Mercury Grand Marquis

Sorry, I have been busy recently and forgot to update my test vehicles. But here are the results, and these lights are 11 months from recent restoration. And they look bad. Neither coating is holding up, but this car is outside 24/7 and is rarely washed. So it goes through extreme testing with the weather.

Drivers side opti coat

Before washing, very dirty.

After washing with optimum no rinse. The more time goes by the more the lens degrades.



Passengers side Spar urethane treatment

Before washing, bird droppings and bug splatters

After washing with optimum no rinse. More bug splatter etching and its permanent. Opti coated side did not have any major etching like the spar side from bug splatter.



Neither lens looks that good at this point, but the spar looks slightly better. I am guessing both lens will need to be re done sometime this summer. The other two test vehicles are still holding up but they are garaged and cared for more often.

[mikeCL]

That looks better then others I've seen with a total cloud over.

[ray6]

Assuming all the original coating was removed when you restored, when you see heavier deterioration at the top, it's probably be due to that surface receiving more UV than the rest of the headlight. If you wait long enough, the entire headlight will cloud starting from the top and working down.

We use a polyurethane coating, not minwax/MS but probably similar. However, our coating is much thicker than a 50/50 mix. The thicker the coating, the longer the lifetime, but the more difficult it is to apply.

We now only use poly for low end restores (fleets, buy here-pay here, etc.) but we are guaranteeing for 1 year. Few callbacks, but some, especially PT Cruisers because of their horizontal surfaces. They get hammered with UV.

You might try the following to get better lifetime:

Don't sand any finer than 1500 grit. The rougher the surface, the more surface area to stick to.

Make sure surface is spotless before applying poly. We scrub twice with blue lint free scott towel and Propanol. Don't use any alcohol with water in it like rubbing alcohol.

Make sure the cup you mix in isn't coated with wax, like a paper cup from McSonald's. HDPE or PET is best.

You want as heavy a coat as you can apply, Not familiar with Minwax, but would start ay 100% if possible. A heavier coat is thicker and dries slower, giving you time to work the coating. We apply with closed foam applicators wiping on with horizontal strokes, followed by wiping vertically. This smooths out the coating and gives you a uniform thickness. This should last longer. If you're charging money for your restores, I would try using a better coating like 2K LPE. This is what we use on most restores and warrant for 2 years (with 2 coats). The actual cost per headlight (2 coats) is less than a dollar. Poly is probably a quarter, Not worth the risk.

ray6

[HotRod]

7 month update on test vehicle #3 Pt Cruiser

I just got around to inspecting my third test vehicle, which is daily driven but washed regularly and stored in a car port when not in use. Neither light looks much different than the day I restored them in my opinion. Both lens are holding up very well on this car but remember this car is taken care of better than the Grand Marquis.

And here are some pictures:

Spar urethane side 7 months since restoration




Opti coated side 7 months since restoration




The slight ghosting effect at the top of both lights is on the inside on is non repairable.