Sanded my headlights - then fucked it up
 

For stupid reasons I decided to sand down my headlights in order to restore them, but now I can't fix it.

Multiple times I wet sanded it down with 800-1000-2000-3000, then I either applied clear coat or buffed it with PlastX, but no matter which method I use it sucks.

The PlastX left blotchy patches on headlight that wouldn't buff out. The best results I've gotten so far was to go straight clear coat after the sanding, but it looks uneven/gritty afterwards. How would I fix that?

Am I supposed to use PlastX after clear coating it?

800 will have put deep scratches in the plastic.
Remove the lights from the car
wet sand with the 3000 to get a uniform smooth surface, a surface microscope will be helpful to see how you are doing ,this will take a while using a random sander or a DA.
Then use 3M professional grade polishing compound with a foam pad, all three grades one after the other. This will also take a while.
Clean thoroughly with solvent that will not harm the plastic.
Finally coat with a headlight restorer from someone like Maguire's.

What clear did you use? I only sanded with 400 and my painter friend cleared them while he was painting a truck and they turned out great.

My knowledge here is less than others - so take this for amateur advice. Pics will help here.

My guess is that either:

A) PlastX combined with the material you used for application is not aggressive enough to follow the wet-sanding, even something as fine as 3000 grit, and that you need an intermediate for optimal results. M105 would be a splendid choice, capable of removing severe defects from paint and headlights alike, and you could stop at 2000 grit. In this case, I would expect the remaining defects to be deeper/more pronounced.

---or---

B) PlastX combined with the material you used for application is too aggressive, or you are not working the diminishing abrasive through its entire polishing cycle. This type of abrasive features an extended work cycle but is prone to underworking where someone stops before the abrasives have decreased in size enough to remove the initial defects they cause earlier in the working cycle (someone smarter than me could explain this better). The potential solution is working a longer cycle, using consistent pressure throughout with less pressure towards the end, and/or using a less aggressive pad (or, starting a work cycle with a more aggressive pad, and switching half way through to a less aggressive one after the abrasives have begin breaking down - although this is probably not necessary). In this case, I would expect the residue to be more shallow and superficial.

---or---

C) It has to do with the actual wet sanding itself where the different stages are not fully completed before moving to the next step - I know very little about this, other than when I have wet sanded headlights before and did not spend enough time on each step there were deeper scratches left behind.

• How are you applying? By hand, DA, RA, or one of the drill attachments?
• Did you use wool, foam, or something else? How aggressive? How much pressure? How many independent cycles?
• Are you working the polish through its entire cycle? I'm not sure how aggressive PlastX is, but in the case of moderately aggressive DAT compounds (like Ultimate Compound), if you underwork them you may fail to remove the superficial defects the abrasives initially cause and especially with a DA this can result in a 'cloudiness'.

The best luck I've had with headlights is a combination of M105 + wool, followed up with a much less aggressive polish (like UC) + less-aggressive foam to remove the marks left from the first cycle. (IMamateurO this eliminates the need to sand with headlights in the overwhelming majority of cases.)

The process was:

Wet sand with 800-1000-2000-3000, then either:

A: apply PlastX by hand, which didn't buff anything out
B: apply by drill attachment at 1500rpm, which caused blotches
C: Apply layers of clear coat and leave as is, which turned out a little foggy/gritty and I could see scratches on the inside
D: Apply clearcoat, then sand it down with 2000 just enough to even it out then buff it out, which also caused blotches with PlastX

I will be honest with you: if I had the tools for what you suggested, I'd be more than willing to try to keep fixing it. I screwed myself in trying to fix something that wasn't necessarily broken, and I paid for it (literally about 80$ down the drain due to all the different methods I tried).

I feel that it's something I need to learn by watching someone do this in front of me and follow it right behind, because none of the YouTube videos helped: everyone made it look so easy, and NO ONE had any of these issues I had.

Again, I'm almost giving up on it. I might try the sanding once again with what I have and try a different method, I'm not sure, but if it fails I might just say "fuck it" and buy new ones. I'm an extremely noob when it comes to mechanics and manual labor, and I have fun doing things and trying to learn, but this has brought nothing but headaches for me and my girl, who I keep snapping at because I keep failing at this.

Hell maybe I'll buy new ones, pull these out and try to learn how to fix it then. At least I won't bave a timeline and my car will be drivable.

buy any random headlight from a junkyard or ebay and practice on it. It's all in the prep, in this case the sanding. I don't know what is plastx but after you finish sanding it should feel smooth to touch and you can just use a rubbing compound by hand. Those drill attachment probably creates a lot of heat which is not required to fix up your headlight lens.

Does the drill attachment have a DA action?
Is the pad wool or foam?
Are you priming the pad correctly? (and periodically lubing it, if necessary?)

If the pad is wool, and the drill does not have a DA attachment, this could be an outcome of the nonrandom action of the drill + a heavy cutting pad as such + more pressure (not unlike that of a rotary buffer).

It is wool, and this would happen within a few seconds after starting (like 2-3 or so seconds). I gurss it dried up way too fast.

I have this cheap Black and Decker Drill that I bought a 3m buffing adaptor for, and that's what I was using. I think it's this guy

https://www.homedepot.com/p/BLACK-DE...FRJkfgodYNwLNQ

I haven't done plastic in forever but it sounds like the drill attachment/use is the problem, over heating the plastic. 1500 rpm sounds really high to me. You can do plastic by hand, just be patient and keep everything lubed with compound (or water for sanding steps). Too dry on the sandpaper will also cause issues, grinding in stuff you've removed. Working under a light stream of running water is ideal.

Also, you only need to step back one grit usually. If that's not cutting enough, try one more. Patience is the key.

With all the time, effort and products you're putting into this restore, you should probably just cut your losses and buy a used set from someone one the board. They should cost somewhere around $100-$200 total.

What I don't understand is why this was necessary in the first place. My car is only a year younger than OP's. I have 85K miles on it in various driving conditions, including heavy UV conditions in Texas and Florida. My headlights are nowhere near needing to be reconditioned.

So what was wrong with these headlights to require all this sanding and polishing?

I tend to overdo things and this was another case. It had some yellowing and fogging around the top of the cover and had a few "rock chips" so I figured "hey, let me sand this down to clear it up and make everything nice and even again." And now we're here.

I think this is the issue, and I believe proper pad priming and (possibly) lubrication (spritz of quick detailer will do) may reduce or avoid this, along with using only enough pressure to make the lightest surface contact.

I see.. I'll get these out in the next few days and try it again. We'll see how it goes. Thanks!