Advice on restoring headlights

[davidc11291]

I've done a couple of headlight restorations lately, and have a few questions about sanding technique. Instead of adding to the monster 90 page long headlight thread, I decided to start a new thread.

1) If I'm wetsanding by hand, I sand with my right hand and continuously squirt water with my left hand. My paper is constantly being flushed with water, never clogs up, and lasts waaaay longer. If I use a drill to sand, I have to stop every minute or so to wash the slurry off of the headlight, apply water, and clean my paper. This slows me down A LOT, eats up my sandpaper super fast, and I can't have a constant flow of water running over the headlight. I run thru about twice as much sandpaper if I'm using a drill, and I can actually get the job done faster when doing it by hand. The whole point of the machine is to improve speed. What am I doing wrong?

2) To clean my sanding discs, I'm squirting them with water from a spray bottle. I don't have an air compressor. How do you clean your sanding discs?

3) Once you've got the surface levelled, how many passes do you make in each subsequent step. Here's what I mean- Say you get everything smoothed out with 500 grit, then go 800, 1200, etc. How many passes do you make with the 800, then with the 1200 to make sure you remove all of the previous sanding marks? Doing it by hand, I just sand vertically with the 500, then horizontally with the 800, then vertically with the 1200, etc. This allows me to easily see when all of the previous sanding marks are removed, but if I'm using a drill, it's always leaving circular sanding marks, so I can never tell when I've removed all of the previous sanding marks. I think I end up sanding way too much and taking up way to much time.

4) Using a drill, how many sanding discs do you typically use for each step, not counting the first step. Say you start out with 500 grit then move to 800. How many discs of 800 grit will you normally use on 1 headlight?

[Kristopher1129]

I've done a couple of headlight restorations lately, and have a few questions about sanding technique. Instead of adding to the monster 90 page long headlight thread, I decided to start a new thread.

1) If I'm wetsanding by hand, I sand with my right hand and continuously squirt water with my left hand. My paper is constantly being flushed with water, never clogs up, and lasts waaaay longer. If I use a drill to sand, I have to stop every minute or so to wash the slurry off of the headlight, apply water, and clean my paper. This slows me down A LOT, eats up my sandpaper super fast, and I can't have a constant flow of water running over the headlight. I run thru about twice as much sandpaper if I'm using a drill, and I can actually get the job done faster when doing it by hand. The whole point of the machine is to improve speed. What am I doing wrong?

2) To clean my sanding discs, I'm squirting them with water from a spray bottle. I don't have an air compressor. How do you clean your sanding discs?

3) Once you've got the surface levelled, how many passes do you make in each subsequent step. Here's what I mean- Say you get everything smoothed out with 500 grit, then go 800, 1200, etc. How many passes do you make with the 800, then with the 1200 to make sure you remove all of the previous sanding marks? Doing it by hand, I just sand vertically with the 500, then horizontally with the 800, then vertically with the 1200, etc. This allows me to easily see when all of the previous sanding marks are removed, but if I'm using a drill, it's always leaving circular sanding marks, so I can never tell when I've removed all of the previous sanding marks. I think I end up sanding way too much and taking up way to much time.

4) Using a drill, how many sanding discs do you typically use for each step, not counting the first step. Say you start out with 500 grit then move to 800. How many discs of 800 grit will you normally use on 1 headlight?

Well, first off...it sounds to me by your description that you are wetsanding with 500, and 800. I always dry sand with 500, and 800...then wetsand with 1000 and 3000.

That may very well be part of your problem. As for the time frame or "passes"...I always spend much more time on 500, if I even have to take it there. If I'm using 500 then I'm removing the old acrylic. The 500 is used to remove it, so obviously 500 is more time consuming.

After 500, I probably do roughly 3 passes or so with 800, 1000, and 3000. Call me crazy, but I can visually see the difference between all those grits. So, how many passes I actually make is up in the air. I've done hundreds of headlights at this point, so I'm really in auto pilot when I do them, ha.

As for how many discs are used...I always go through more 500 discs than anything. I will go through anywhere from 1-3 500 discs per light depending on the lens condition. If the old acrylic is brittle, really oxidized, and on it's last leg...I'll only go through one 500 disc per lens. But, when the acrylic is only half gone, and still very well intact on most the lens...I'll use roughly 3.

The 800 discs are always quick work, and typically 1 per light. At times I've used 1 for both lights. The 1000 and 3000 discs I use many times. Most the time I'll use the same disc probably 5-6 times.

Also, make sure you are re-applying the acrylic. Otherwise, all your headlights will fade again in just a few months.

[davidc11291]

How do you clean out your sanding discs when they get clogged up with paint? When wet sanding, do you just squirt them with water? What about when you're wet sanding?

[Kristopher1129]

How do you clean out your sanding discs when they get clogged up with paint? When wet sanding, do you just squirt them with water? What about when you're wet sanding?

I don't really understand what you mean when you say "get clogged up with paint". I never clean my discs...so I don't get that I guess.

I just spray them with water, and keep going. If you mean damp sanding the paint...then even then, paint shouldn't be clogging your paper. You should only have clear coat slurry.

[davidc11291]

I had a brain fart. I meant clogged up with the sanding dust from the headlight plastic, not clogged up with paint. I'm having a problem with the sanding slurry getting gummy and clogging up the discs really fast. I've been wet sanding with 500 and 800. I'll switch to dry sanding those grits like you said and see if that helps.

[604_Snooze]

kristopher, when you say 3 passes, what do you mean by that?

[Kristopher1129]

kristopher, when you say 3 passes, what do you mean by that?

I mean roughly 3 passes from top to bottom. I go back and forth from the top to the bottom, then back up again. I basically mean that I got over the whole lens about 3 total times.

[Kristopher1129]

I had a brain fart. I meant clogged up with the sanding dust from the headlight plastic, not clogged up with paint. I'm having a problem with the sanding slurry getting gummy and clogging up the discs really fast. I've been wet sanding with 500 and 800. I'll switch to dry sanding those grits like you said and see if that helps.

Oh, ok. Then I can definitely tell you that your issue is because you're not dry sanding. Try dry sanding with 500 and 800. Only wetsand with the last two grits.

Those discs are way too thin to wet sand with. They will definitely wanna fight you.