Restoring Clear Plastics e.g., flag window

[Kojiro]

Does anyone have tips on how to restore the clear plastics, such as the flag window? In particular, methods for removing scratches and also how to reduce the yellowing?

[emmadog]

same procedure as for plastic car headlight lenses. there's kits available at auto parts stores or use some Novus 2. some of the yellowing will come off with cleaning and scratch removal but
usually the plastic is somewhat permanently discolored.

[Tink]

Blue Magic metal polish cream and elbow grease.

[Kojiro]

Does retrobrite work on clear plastic?


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[mxfaiman]

Does retrobrite work on clear plastic?

Haven't tried it on clear plastic. But it worked like s&$% on white plastic for me. Didn't work at all so gave up on that really fast.

Colored plastics I just do a fine wet sanding (1500-2500 grit) to remove the top layer of grunge. Then buff them with a buffing wheel and plastic compound. Then wipe down with a final plastic polish. Clear usually you are stuck with deep scratches. Otherwise I use the same method minus sanding.

[riff-raff]

I've always used a very fine sandpaper with lots of water. A 3600 wet&dry and a lot of elbow wear an tear. You might Finnish it with 12000. Try it on a small area first.

[emmadog]

retrobright works specifically on plastic that has discolored because of bromine. it’s not designed as a general purpose cleaner.
I tried it on clear plastics with no luck so I’m assuming clear plastic has no bromine.

[hkp]

I've used Nevr-Dull for light scratches, and cleaning. It's not very abrasive so if you have deep scratches, you would probably want to use more aggressive methods.

[Kojiro]

I decided to try Novus. I've seen some videos on cleaning model plastics with it. I will post if it works

[stampeed valkyrie]

Coming from working on vintage emergency equipment I work on polishing domes frequently.
Novus.. will work. but needs to be done in stages.. 3, 2 and then 1. Make sure you used a powerball to make things easier.
Plastix also works pretty well.. made by Mcquires and is found at most auto stores.

For heavy scratches or heavy yellowing you may need to wet sand the part in question. Start with a lower number grit depending on severity (ex 800) and then work your way up.. (1000,1500,2000) and then finish with a good polish and buff. Most things can be brought back.. I even bring back weathered 40+ year old domes...

[Kojiro]

Make sure you used a powerball to make things easier.

What is a powerball?

[riff-raff]

https://www.amazon.com/Mothers-05140-PowerBall-Metal-Polishing/dp/B0007RDVD4/ref=sr_1_2?ie=UTF8&qid=1510178256&sr=8-2&keywords=powerball+polisher

Powerballs work great. You can use it to polish your car wheels or pots and pans.

[hkp]

And if you win the other kind, you can become rich!

[emmadog]

i’d be wary of novus 3. it’s a pretty coarse grit that may put deeper scratches in the surface than you already have. novus 1 isn’t a polish in the sense of any abrasives present-it’s more of a shine enhancer and protectant.

[Kojiro]

And if you win the other kind, you can become rich!

Ironic. I just won the powerball last night!


just kidding...

[Kojiro]

i’d be wary of novus 3. it’s a pretty coarse grit that may put deeper scratches in the surface than you already have. novus 1 isn’t a polish in the sense of any abrasives present-it’s more of a shine enhancer and protectant.

I am going to try the 3, 2, 1 pattern on a piece of clear plastic that is on the inside of the machine and only a small portion of that part. If it works, then I'll use it on the flag window. If not, well then at least it isn't visible from the outside.

[hkp]

Novus was made for plastic, so you can't go wrong with it. I don't know how badly scratched, or discolored your clears are, but I use the Nevr-Dull for polishing scratches out of plastic watch crystals and other stuff that isn't too bad.

[emmadog]

good idea to try on a test area first.
i made this 6 foot by 15" piece of acrylic art out of around 600 individual pieces of acrylic. i calibrated my table saw to be within a couple thousandths of parallel with the miter slot but when gluing up the pieces in the jig, there were still edges that stuck out a bit to include adhesive squeezing out. i used fairly coarse paper to wet sand it flat and used a couple bottles of novus 2 to get it really smooth. after that i wet to 12,000 grit for the final polish.