how to polish plastic/ revive light assembly

[the nice machine]

okay first off sorry all of the oics are out of focus, the auto-focus on my cheap ass camera isn't working and there is no manual setting. if you've got a digital SLR for sale or trade pm me... i will put it to good use.

so i'm currently rebuilding my 620, one of the chores on the list is freshening up all of the plastic and light assemblies. i figured i might as well take some pictures of the process. i've only been working on cars for a year now so i'm a beginner as far as automotive stuff goes, but i've been polishing random materials for a few years. i've done a lot of plastic.

this is the subject: looks okay, could look better. (sorry again about the focus, yuck)

here's the bad news: if you want to get them shiny, no more cool japan stamp

take your lense and wash it with some dish soap.

wet sand it. for plastic i use 220 grit, then 500, and then 1000. the buffing compound will do the rest. we'll get to that in a minute.

use a sanding block, if you don't have one a moist sponge works well. start with the 220 grit sandpaper.

okay plastic is really sensitive stuff. you want to keep your sandpaper clean. sand your piece in a circular motion, shift the weight around (they aren't perfectly flat) and make sure to get all of the deep scratches out . keep rinsing the sandpaper clean every 30 seconds or so.

once you get to the end of the 1000 grit part, it should be a uniform haze with no scratches. whoops i missed a spot.

at this point you need a loose buffing wheel cloth, the soft floppy kind. i have a stationary buffer. you can use a corded drill with a wheel cloth rigged to it and clamp it to a vice. you can make one with a wood lathe. once you have the cloth part there are several ways to make your own buffing wheel. i bought one because i use it all of the time. note the direction the wheel spins. very important if you make your own.

you also need soft buffing compound. i use stuff from harbor freight. the blue stuff.

PUT YOUR SAFETY GLASSES ON!

turn on the wheel. whatever you use for a motor to rotate it, don't go over the rated rpms for the buffing cloth. a 6" wheel is good up to 3500 rpm's i think? not sure check the label. take the compound and rub it on the wheel until it starts to grind away. this is "loading" the compound onto the cloth.

hold firmly onto your piece and start buffing! keep it moving, back and forth, up and down. map it all out and keep rotating and moving it so that it doesn't get hot. it will melt and the surface will get all messed up... keep it cool.

you'll start to see it get shiny. keep going. some black stuff might smudge up on there, but you can wipe that off with a cloth.

one side done.

you can keep your wheel clean by rubbing a towel on it.

shiny!

one last step for the plastic. shine it with good old carnauba wax, it will help protect it from scratches. better yet, you can use clear shoe polish it is even stronger.

you love your datsun, might as well shine the screws too.

*make sure to dip them in wd-40 afterward to slow down tarnishing

for this you want a stitched wheel. it is much stiffer.

and some grittier compound.

same technique as the plastic, now you can do the trim, too.

 

and to clean up the inside of the housing i am just using #00 steel wool. that's about the grittiest wool i would use. tomorrow i will soda blast it, but it is late at night. this works just fine, too. if you have any built up crud on the light terminals, get them clean with a wire brush or 220 sandpaper.

before

after

scrub down the rubber part with a toothbrush and dry it off thoroughly. give it a few sprays of armorall or any rubber protector stuff. this will make it look darker and help protect it from sun damage and cracks.

 

shitty pic, but trust me this thing shines.

and that's it. make sure to let everything dry out really good before you put it back together. it might even be a good idea to coat the metal with a tiny bit of wd-40 to prevent rust.

alrighty then. the nice folks of ratsun have kept me on the road with tons of advice and knowledge, i felt like i should contribute something i know. so here it is. i hope this helps somebody out there. thanks!

[the nice machine]

this is also how to fix cd's and dvd's. yep, i dumpster dive the shit out of music and movies.

[BRE510]

:thumbup:

[ggzilla]

nice How-To! Pictures aren't too bad, but if you hold the camera farther away they will be clearer.

[DanielC]

Good write up.

When polishing plastic, you must keep it cool. I have polished the plastic headlights on my Ford Aerostar, using a rotary buffer, and actually just about any polishing compound, again the key is to keep the plastic cool. Use slow speeds, light pressure, and keep it wet.

[Ratwagon1600]

Good read, well done!

 

Use almost exactly the same method myself except I wash my lenses first in the dishwasher ( when the wife isn't home).

 

I'm also lucky enough to have a bead blasting cabinet which uses glass microspheres to clean the crap off things.

 

great for cleaning up the lens housings and other stuff.

 

Agree with Daniel, you need to keep the lenses cool as its very easy to apply too much pressure on the buff.

 

Cheers

 

Jason

[the nice machine]

Good read, well done!

 

Use almost exactly the same method myself except I wash my lenses first in the dishwasher ( when the wife isn't home).

 

I'm also lucky enough to have a bead blasting cabinet which uses glass microspheres to clean the crap off things.

 

great for cleaning up the lens housings and other stuff.

 

Agree with Daniel, you need to keep the lenses cool as its very easy to apply too much pressure on the buff.

 

Cheers

 

Jason

thanks!

yeah i have a blast cabinet too, it was too late at night to run the compressor.

i am going to use baking soda to blast those inside metal parts, the advantage being that it is water soluble. glass beads, sand, aluminum oxide, they would all work but you don't want sand in your light sockets. baking soda is easier to clean up and a really mild abrasive so it will leave the metal a little bit shiny. i wanted to keep the how-to cheap, steel wool costs a lot less than a blaster setup.

[MikeRL411]

Wood working shops sell 0000 steel wool used for final polishing on veneer finishes. Also, I have used 4000 grit "Crocus Cloth" to do final wet polishing on enamel paints, might be hard to find but it's great! I used it to finish an outside plastic mirror housing that had been scratched up. It looks new. I won't tell you how much the body shop [or new Nissan parts] wanted but the crocus cloth cost me less than $5. The water was "free".

 

I wonder if the currently advertised wipe-on wipe-off [undoubtly with some intermediate steps] solutions for fogged over integrated headlight assemblies might do the job here? Looks like they address surface crap and not UV deterioration of the basic plastic so there might be some hope here.

[the nice machine]

Wood working shops sell 0000 steel wool used for final polishing on veneer finishes. Also, I have used 4000 grit "Crocus Cloth" to do final wet polishing on enamel paints, might be hard to find but it's great! I used it to finish an outside plastic mirror housing that had been scratched up. It looks new. I won't tell you how much the body shop [or new Nissan parts] wanted but the crocus cloth cost me less than $5. The water was "free".

 

I wonder if the currently advertised wipe-on wipe-off [undoubtly with some intermediate steps] solutions for fogged over integrated headlight assemblies might do the job here? Looks like they address surface crap and not UV deterioration of the basic plastic so there might be some hope here.

i used to wet sand all the way up to 4000, then all i had to do was buff it with turtle wax to get it shiny. it was too labor intensive and the sandpaper ended up being more expensive than buffing compounds. so yeah, if there is a part you can't get to with a wheel, you can just sand up to about 4000 and get the same effect.

there are lots of ways to polish, it really depends on the size of what you are working on. i've made a few epoxy resin table tops, when you pour resin you still want to sand and buff the surface to make it perfect and more scratch resistant. so for those i use a flat sanding block and wetsand it up to about 2000, then i use a hand held variable speed buffer and some auto paint rubbing compound and cut+buff the surface.

i'm not sure what wipe on wipe off product you are talking about, sounds like it is a plastic polish? if that is the case it is really just some kind of wax that fills scratches but doesn't really do much else.

[DAT510]

:thumbup: :thumbup: :thumbup: :thumbup: :thumbup:

[thatguy]

Nice work.

Correct me if I am wrong, but doesn't placing the lenses in boiling water do a pretty good job?

[the nice machine]

Nice work.

Correct me if I am wrong, but doesn't placing the lenses in boiling water do a pretty good job?

mmmmm... maybe, i don't like subjecting plastic to extreme temperatures though, so i wouldn't.