Wet Sanding Plastic

[SailCat]

Another question on headlights and other plastic light lenses. I have read a lot of posts on wet sanding and the various grades of paper needed for the job but I must have missed how they are used. I have a brand new 3/8 VS reversible, high speed, HD, Porter Cable drill. It is A/C. Also have a 1200 watt inverter that powers it easily.

Is hand sanding or using a drill or polisher the way to go?


What sort of lubricant (if any) do you add to the water?


What type AND size of backing plate or hand block for each? It would have to be soft?


I have one kit with Red, gray, and white "scuff pads". Any good?



Where does one buy 1500-2500 grit cut in disks with Velcro backing?


Or dump the wet sand and use various polishes? Which ones?


Thanks as usual,



Jay (Thinking this newby has an awful lot of questions)

[GeorgiaHybrid]

Jay,

I wet sand by hand only. Depending on how bad the plastic is, I start with 600 or 800 grit paper. Going from there to 1000, 1200, 1500 and maybe 2000 (depending on the plastic). Make sure that each grade of paper is done 90 degrees to the last grade. IE 800 grit left to right, 1000 grit up and down, 1200 grit left and right, etc.

Lube is soapy water. Experiment with what you have to get a good ratio of soap. Soak your paper at least 4 hours prior to using it. Keep the paper wet (and the plastic) by spritzing with a spray bottle as you sand.

I use a small rubber eraser as a sanding block (think pink pearl here or stadler mars white vinyl) with the paper cut into sections large enough to wrap around and grip. When you start, the residue will be yellowish in color but as the oxidized layers are cut away it will become white.

Make sure to tape well before starting and you might need to dry and re-tape after sanding and before polishing. Polishes that work vary by person and equipment. I bought the Diamonite kit to see if it worked better than my PC but didn't like it as well. The lights jeweled better with the DA as the plastic is very soft compared to most paint and left some faint swirls with the drill (big DeWalt drill with too much torque).

Others have had great sucess with the kit though so give both of them a try (as well as a rotary) to see what works for you. Good luck.

[SailCat]

Originally Posted by GeorgiaHybrid

Jay,

I wet sand by hand only. Depending on how bad the plastic is, I start with 600 or 800 grit paper. Going from there to 1000, 1200, 1500 and maybe 2000 (depending on the plastic). Make sure that each grade of paper is done 90 degrees to the last grade. IE 800 grit left to right, 1000 grit up and down, 1200 grit left and right, etc.

Lube is soapy water. Experiment with what you have to get a good ratio of soap. Soak your paper at least 4 hours prior to using it. Keep the paper wet (and the plastic) by spritzing with a spray bottle as you sand.

I use a small rubber eraser as a sanding block (think pink pearl here or stadler mars white vinyl) with the paper cut into sections large enough to wrap around and grip. When you start, the residue will be yellowish in color but as the oxidized layers are cut away it will become white.

Make sure to tape well before starting and you might need to dry and re-tape after sanding and before polishing. Polishes that work vary by person and equipment. I bought the Diamonite kit to see if it worked better than my PC but didn't like it as well. The lights jeweled better with the DA as the plastic is very soft compared to most paint and left some faint swirls with the drill (big DeWalt drill with too much torque).

Others have had great sucess with the kit though so give both of them a try (as well as a rotary) to see what works for you. Good luck.

Thanks GH!

You are EXACTLY why I come here. Straight personal experience, freely given. I'm sure others have different experiences but all are given in the spirit of learning all we can. I have to wonder how long it takes to refinish a moderately corroded pair using manual sanding?

Thanks again,

J

[GeorgiaHybrid]

Once you are setup, it should take anywhere from 30 minutes (easy) to an hour (medium) up to an hour and a half (bad news) for the pair. Just remember to do both at the same time. Don't finish one and stop to admire the good job you did. Sand both with one grit, change grits, sand both, polish both with the same polish, etc.

If they are not bad, 15 minutes for the pair for just a polish would be about right.

Being in a high dollar town (vacationed there on the end of July, first of August), price your work accordingly and good luck.

[Jimmie]

I agree with GeorgiaHybrid on using a PC vs your drill. You need a corded drill (takes too long for a battery drill). The corded drills have too much speed and torque. They can damage the plastic unless very careful.