Wetsanding practices

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As I recall, I have never wetsanded anything before. That being said, I'm a bit weary of wetsanding the headlamp on my Miata. It's a little yellowed and has some UV cracking. Not terribly, but the other headlamp looks pristine and I want them to match as closely as possible. I was planning to start with a 600 grit, then move progressively to a 3000 grit before moving to a rubbing compound, then ScratchX, then finishing with some Ultimate polish and headlight UV protectant. That all seems fine, but I have some questions. 1) How long do I spend on each grit level, and 2) do I use soapy water or plain water? Just wanting to make sure I do it right the first time and not have to worry again.
 
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Is the lense in need of sanding? Will a polish be enough to start with? Whichever grit you use or start with, use lots of water so the sandpaper slides nicely across the lenses. I like soapy water but, as long as the sandpaper is wet, you'll be fine. Keep a bucket of water next to you Let your eyes and finger be your judge. Sand for a little bit...stop and look/feel. 600 grit is a good starting point and you can always go back and do it again.
 
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Klutch9

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Char, I did already try polishing/compounding but the result still isn't quite as good as I'd like. As far as I can tell, the haziness is not on the inside of the lens, but I suppose it's hard to tell sometimes. The lens doesn't seem to have any oxidation, just a faint haziness, which I'm assuming is coming from the cracking. ???
 
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Originally Posted By: Klutch9
Char, I did already try polishing/compounding but the result still isn't quite as good as I'd like. As far as I can tell, the haziness is not on the inside of the lens, but I suppose it's hard to tell sometimes. The lens doesn't seem to have any oxidation, just a faint haziness, which I'm assuming is coming from the cracking. ???
What was used to apply and work the polish/compound onto the headlights, elbow grease or a powered device (like a D/A polisher or cordless drill attachment)? It has been my experience that elbow grease is not enough to get the job done when using your typical polish/compound to refinish headlight lenses.
 

Klutch9

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Originally Posted By: The_Nuke
Originally Posted By: Klutch9
Char, I did already try polishing/compounding but the result still isn't quite as good as I'd like. As far as I can tell, the haziness is not on the inside of the lens, but I suppose it's hard to tell sometimes. The lens doesn't seem to have any oxidation, just a faint haziness, which I'm assuming is coming from the cracking. ???
What was used to apply and work the polish/compound onto the headlights, elbow grease or a powered device (like a D/A polisher or cordless drill attachment)? It has been my experience that elbow grease is not enough to get the job done when using your typical polish/compound to refinish headlight lenses.
I was using a cordless drill attachment. The reason I concluded that wetsanding was necessary was because of the UV cracks. If it were just surface oxidation, I don't think wetsanding would be in order. But in my case, I think a layer of plastic has to be removed to address the cracking. Hopefully they aren't too deep. As I stated in a previous thread, the foggy headlamp in question has a perfectly smooth surface after my polishing.
 
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Originally Posted By: Klutch9
I was using a cordless drill attachment. The reason I concluded that wetsanding was necessary was because of the UV cracks. If it were just surface oxidation, I don't think wetsanding would be in order. But in my case, I think a layer of plastic has to be removed to address the cracking. Hopefully they aren't too deep. As I stated in a previous thread, the foggy headlamp in question has a perfectly smooth surface after my polishing.
Yeah, that is beyond the polish/compound stage then...if you are going to sand, go with Char Baby's suggestions, that should get you as close as possible to the result you want. Although, if it were me, I would be worried that I would spend the time and energy to do the wet-sanding only to find the end result still wasn't what I wanted...or that the cracks were just too deep to cure with the sanding. So I would probably try to find some replacements in good condition at a local wrecking yard or on CraigsList first.
 

Klutch9

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Originally Posted By: The_Nuke
Originally Posted By: Klutch9
I was using a cordless drill attachment. The reason I concluded that wetsanding was necessary was because of the UV cracks. If it were just surface oxidation, I don't think wetsanding would be in order. But in my case, I think a layer of plastic has to be removed to address the cracking. Hopefully they aren't too deep. As I stated in a previous thread, the foggy headlamp in question has a perfectly smooth surface after my polishing.
Yeah, that is beyond the polish/compound stage then...if you are going to sand, go with Char Baby's suggestions, that should get you as close as possible to the result you want. Although, if it were me, I would be worried that I would spend the time and energy to do the wet-sanding only to find the end result still wasn't what I wanted...or that the cracks were just too deep to cure with the sanding. So I would probably try to find some replacements in good condition at a local wrecking yard or on CraigsList first.
The time involved isn't really an issue, since I always like a little project. My only additional cost would be the sandpaper, since I already have a host of polishes and compounds on hand. I've been looking at replacements, but they're surprisingly expensive for the Miata. I can't even find a knockoff ebay unit!
 
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I do these daily. Can you post a picture? Will be more telling to see if they can be refinished successfully. In my experience, most Asian headlamp units refinish quite nicely. :-) Your refinishing plan is much like what I do. If the lamp looks "cataract"- I start with 600 to remove the oxidation and weathering. I move to 1500 and then 3000 3M Trizact. I machine polish to a smooth finish and then seal with Pearl Oyster sealant. In the end they look fantastic and are well protected for the years to come with proper maintenance.
 
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I do not have as much experience with headlight restoration as some dealers, but this is generally what I've seen. You can fix the issue, but keeping the lenses looking clear is the tough part. It seems like the aftermarket doesn't have a easy solution for duplicating the factory UV protection (and finish). There are some detailers out there who are spraying clear coat onto the headlight after restoration, but I am not familiar with that practice. As an alternative, you can try Opti-Lens (i've done a few), but I have no long-term experience with the product. The commentary on the professional groups is that there've been some mixed results. For sanding, on a number of headlights, I've been able to do 1000 -> 1500 ->2500. Depending on the sandpaper you use (I use Meguiars uni-grit), you only need to make the surface damp. Too much water can actually be detrimental, as we learned from the Meguiars NXT class. Be sure to sand to at least 2500 as it's tougher to remove sanding marks from headlights than paint. I would usually go straight to wool/M100, FG400 or M101 followed by HD Adapt or M205 on a light cutting foam pad to remove the micro marring from the compounding stage, followed by HD Polish on a foam polishing pad to finish down well. If you're coating a light, then a few IPA wipedowns afterwards will be needed.
 

Klutch9

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Thanks to all for the advice! I got around to sanding yesterday. I did 400 grit, then 800, then 1000, and finished with 2000. With a drill attachment, I applied some Turtle Wax rubbing compound, then ScratchX, then finished with Meg's Ultimate Polish. It came out incredibly smooth, and almost all of the UV cracking was gone (save for a little bit on the veeeery top). However, the lamp still is not 100 perfect, because there is indeed some yellowing either on the inner surface of the lens, or the entire lens itself has been UV damaged all the way through. I also saw about a 4mm oxidation patch on the inner side. However, I'd put the lamp at about 95% good, and I'm happy with it. By itself, it looks brand new. It's only when you compare it to the driver's side lamp that you can tell it's not quite as good, but you have to look to notice. I'm sure most people can't tell the difference. I finished by applying 2 coats of Meg's Headlight Protectant, or whatever it's called. Hopefully that will stave off further UV damage for awhile. I'm going to apply a liberal coat probably once a week for awhile to build up a layer. Pics will be up soon!
 

Klutch9

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Here are the pics. The first 3 are of the passenger side headlamp, which is the one that was wetsanded. The 4th picture is of the driver's side headlamp, for comparison, which looks crystal clear and needed no work. Sorry if the pics aren't super clear. The "bad" headlamp also had the sun beating on it more than the "good" one did in the pictures. Cell phone + blinding sun will only yield so-so results grin
 
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Nice work! I wonder how a coating meant to protect acrylic/lexan would work here, such as Novus plastic polish #1? I use it around the house on many things, it has no grit, not sure if it has a UV blocker in it though for outdoor use.
 
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I just ordered some 3M sandpaper from amazon. Includes 1 sheet of each 1000,1500 & 2500 and 2 sheets of 200 costs about 4.50$. Although i will be doing mine by hand.
 
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Looks awesome. I have wet sanded my headlights multiple times over the years but never using a sealer in the end. Last time I did the process was over a year ago and I finished by coating with wax. This has been looking to hold up pretty well. I have used novus 1/2/3 for years. 1 is basically a cleaner and in no way seals. I was searching for products before anything was on the market. I have also tried many things and if the product does not involve some type of headlight sanding then don't expect results. Here is a post from 2005 bitog where I mention the product and process. I still have the same bottles of novus. http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/593766/Re:_Wax_on_headlights#Post593766
 
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I just did some VW Beetle headlights that were the worst i have ever seen, you couldn't even see the reflector. The car failed inspection before i got it for these, at over $700 a pair for OE it was time to experiment. There was nothing to loose at this point, it either comes out okay or it gets aftermarket junk (the worst option IMHO). This was done with the lights removed from the car. I used the common stuff almost everyone has at hand or is inexpensive. I used a 4" square oscillating sander, a 6"x4" could also be used, loaded with 2000 wet/dry. *Wash the lens in the sink (i used a big shop sink) with warm water and Dawn, rinse and leave wet. *Smear a little Dawn on the wet lens and start using the sander on it, throw a little water on the lens if it gets dry. Keep the tool moving and the lens wet. *Continue until the lens is a uniform haze and looks nice and clear when wet with water. The next step use a round 5 inch orbital sander with a couple of cheap HF hook and loop pads. One orange and a black. No need for a dedicated polisher or high dollar pads, these are cheap enough to throw away after. *Put the pad on the round sander, damp the pad with a spray bottle and spear some rubbing compound on the lens. *Polish the lens, stop when the compound begins to go dry, wet the lens with more compound and water. *Continue until lens is clear, it will still have a haze from compound. *Switch to the black pad and use a plastic polish, polish until the lens looks like glass (it will). *Wash the lens again with dawn and water thoroughly then rinse and dry. You will need a spray can of U-POL UV resistant clear. *Mask off anything you don't want sprayed, wipe the lens with a tack cloth or microfiber. Never use red shop rags they contain silicone. *Spray one thin coat, wait 10 min then another thin to medium coat. do not spray this too heavy it can go off color. *Let dry at least 5 hrs before handling. Note. Use a plastic polish like Novus 2 that does not contain protectants like the Meguiar's G12310 PlastX that will prevent the clear from adhering properly and may cause fish eyes. http://www.amazon.com/U-Pol-Products-0796-Clear-CLEAR/dp/B009LHER0M http://www.amazon.com/NOVUS-Plastic-Fine...+plastic+polish http://www.amazon.com/3M-03900-Rubbing-C...ubbing+compound The VW lights came out like brand spanking new, absolutely crystal clear. The clear will protect them for years. It is made for this job. For sanding i only used 2000 wet and dry, Dawn and water, nothing else. Let the machines do the work.
 
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^ VW's always seem to be terrible.. My Jeep isn't too far off though.. I think they changed the plastic formulation on the later models thankfully. I am about due for a wet sanding treatment myself.
 
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