Customs Cleaning/Restoring Vintage Plastic Tail Lights

My mechanic busted one of my 52 Kaiser Manhattan tail light lenses while my car was in the shop. I was able to find replacements, but they’ve seen better days (dirt, gunk, superficial hairline cracks, etc) aside from the fact that they’re 68 years old and fairly brittle.

Does anyone have any tricks for getting these clean without threatening the integrity of their already brittle plastic?

I read something about using toothpaste to fill those small cracks. Has anyone tried this who can vouch for the method?

Much appreciated!!


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Dish soap and water is how I'd kleen them. I've sanded the lens down with a red scotch brite and cote them with clear cote paint. Wow do they look nice.

 

Yep, that's what I've found works best too. Use an old tooth brush to scrub the inside, if the outside isn't too scratched up - then using a dab of almost any polish - I've used everything from Brasso, aluminum polish, and many other polishing compounds I had alying around - they all seem to work the same - really good when you rub the lenses out using an old sock or shirt. Clearcoating them will help seal any superficial cracks - just don't polish the lenses first then paint them - the clearcoat will peel off (I learned that years back)

 

600, then 1200, then 2000 grit wet sand.
And clear coat them afterwards.

A lot more work but certainly better than toothpaste [or those headlight restorer kits]

 

An old guy vendor at Hershey turned me on the spraying old plastic lenses with WD40 after cleaning with dish soap and water and letting dry. Let it soak in a while and wipe down, works well for me!!

 

Toothpaste is an old modellers trick for polishing plastic car bodies....use the cheapest standard white toothpaste, there is also a plastic polish called Novus available from plastic sheet supply companies, also any mild abrasive such as alloy polish, brasso or silver polish, also try cutting compound used to buff out paint.......I'd clean the lens with warm water, dishwashing liquid & someone you don't likes toothbrush.......then polish the outside.........andyd

 

Second the Novus comment. There are 3 types ranging from very aggressive to fine polish. Really works.
Wash to get the grime off then use Novus to detail.

 

Warm water and soap to wash em...wet sand with as fine as ya can to do the job...600-800 is a good start...go up as fine as ya can 2000-2500..go buy a 3” hookit it back up pad for your angle grinder and some white 3” buffing pads, put some compound on there and polish away..they will look great..obviously hairline cracks and “spiderwebs” in the plastic will still be there, but they will be shiny..

 

Hobby shops should sell a kit for polishing model car paint. It has several foam pads with different, progressive, grit sanding surfaces. I think it starts at 600 or 800 and goes up to 12000 or something ridiculous. Then polish. The headlight refinish kits should work too. For filling the cracks, maybe super glue.

 

Toothbrush and Dawn dish soap is where I’d start. Then, depending on the grime involved, Scrubbing Bubbles is pretty good on plastic cleaning. Third choice would be the Simply Awesome cleaner from the Dollar Store.

Novus plastic polish is good stuff. Get some #2. Try a local motorcycle shop, it’s also good on windshields and face visors.



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Use one of those kits with the buffer ball for polishing late model plastic headlights. It’s like it’s designed for plastic tail lights!

 

I had the glass lenses in my 35 Chevy repop'd by Classic Plastic down here in red and amber configuration. Not original however you could replace OEM lenses with these as they are UV treated. Mine are over 15yrs old now and still in great condition.

 

I'm starting a small project on a vintage plastic taillight shortly. I'll be soaking the rubber seal in Wintergreen Oil to soften it and save it. The plastic lens will get a soak, too, because the rubber can't be removed without crumbling. I have a hunch the plastic will also benefit from the treatment. I also will polish the lens and give it a special coating.
The plan is to post a How To thread with the results in a month or so.

 

Thank You to everyone who responded!

I soaked em in Meyers dish soap and quick buffed em with toothpaste and a rag. They looked better but definitely didn’t look great. I talked to an old timer about any tricks, and he told me to lather them in lard and let em sit for 48 hours. That the lard should soak into the cracks and fill em out. Seemed worth a shot since I had all that stuff in the cabinet already. This evening will mark 48 hours so I’ll keep everyone updated.

However, the general consensus here seemed to be that Novus is the way to go, so I ordered some of that from Amazon and it should be here tonight.

I’ll post pictures of the lights post-lard, pre-novus. Then another one post novus.

Here’s where they’re at so far:




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If you are going to clear coat them, I wouldn't want anything filling the cracks but the paint. I'd get an old tail light that isn't worth anything and practice on it before doing the important ones. Then you can see what works.

 

My rear lenses were very very badly crazed and going very pale red from sun exposure.

https://www.tamiyausa.com/shop/spray-ts-plastics/ts-74-clear-red/

Clear red lacquer that'll stick to a lot of plastics including PMMA/Acrylic/Lucite and a few others. Sticks to chrome ok and polished stainless.
For lenses, sand the plastic down as smooth as you can get it then build this up in layers as any other paint.

That's what I started with. White crazed cracks.


Red lacquer to cover up. Still needs polishing up more but the improvement is noticeable, including restoring the color of the light to red, from pale pink when illuminated.

It's a last-ditch but does provide pretty decent results. Is a deep crimson color. I also did my wheel emblems with it.

Phil

 

Wow! Those came out great!!!

All the transparent plastic paints I’ve seen suggested (testor) for fixing crazing online come out too much of a fire engine red, but this deep red is exactly what I’m looking for.

What grit sand paper did you use? I have a mouse sander for small projects, which will make it go faster but it may be too much, so I’ll test on the broken light.

Thank you for this.


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Welp, here’s the result.




This is the left one that was treated with lard and then novus 1, 2 and 3.




Here is the right one just treated with lard before the novus.


As you can see there’s not a lot of difference. The lard polished the lens just about as well as the novus for a fraction of the price, but it didn’t fill any of the cracks as the old timer claimed.

They’re definitely in way better shape than they were when I started, but I’m still going to have to go a step further. I’m going to order the lacquer PhilA suggested and go from there.

The main take away is that lard will work just about as good as novus in terms of being a polish, but it’s possible that you won’t get instant results (these “soaked” for a few days).


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Mine are terrible, with 1/8" deep crazed cracks so I was much more aggressive than you need to be. I would suggest to work by hand. It's a long process but a lot of motorized sanders are no good for strongly curved plastic like that, you run the risk of applying flat spots that really really show up in the sun.

I would be concerned if you used greases to try and fill the crazed cracks. That'll make any surface treatment (paint/lacquer) pull it out of the crack and bubble up. Thoroughly degrease with hot soapy water, soaked for a while.
If the surface is overall good but with small cracks, 1000, 1500 grit then 2000 grit, cleaned with warm water and dish soap and dried thoroughly, then lacquer applied in many thin coats. At 60F it is dry enough not to bloom in about 5 minutes.
Once you've built up, leave it to fully harden for 3-4 days in 60+ degrees dry heat (aka inside) then wet flat it with warm water and dish soap like you would do with any other paint. It polishes up to a reasonable sheen but remains fairly soft for the first week. It's easy to try get ahead of yourself, and flat polishing it early will result in gooey beads sticking to the paper and a ruined finish that you have to take off and start over.

It doesn't go over stamped/cast letters well, it's a bit thin. It'll never fill the crazed cracks but its color is deep enough to mask them once they have been sanded down a little.

Phil

Edit: Found a picture of what it looks like in sunlight.

That's 6 coats onto stainless steel, in bright sunshine, before I polished it (essentially straight out of the can), for an idea of the color. You can start out a light cherry and layer up to crimson. It's a tiny can but it goes quite far- it's designed for painting polycarbonate plastic models.

Oh, and something else- set them raised up off the surface by placing a piece of wood or something underneath and have them "hang in space" rather than the back edge sitting flat on the table. You'll definitely want to get to the back edges and this stuff sticks like Billy-oh to newspaper. Ask me how I know! Also the nozzle on it sprays a fairly tight circular spray rather than a fan like modern aerosol cans. I find 8-12" away about the right distance to spray from but you cannot stop moving at that distance else you'll get runs and sags. Absolute minimum time between coats at 60+F is about 15 minutes, don't try to rush it.

 

Yeah, since you've soaked the things in grease for 48 hours, it's gonna take a week of soaking in soapy water to remove that junk. Try cleaning them multiple times with Simple Green and then a final wash with dish soap water before you apply any paint.

And I also agree with above, that if you try to use a power sander you are causing more flat spots than smoothing. Those curved lenses will need gentle sanding with a soft backer pad.

 

These days you could find a company with a 3D printer and the proper shade of red and have one made if you have one for guidance so they could make a copy, or more if you have a market for them.

 

I've used this with acceptable results. You have to have a good base to start with though. I put a couple coats inside and out on the Buick tail lights on my Model A. It sits out in the SoCal high desert sun and no peeling, hazing or flaking yet.

 

This is a nice thread about several nice techniques to try. For the OP, I hope your mechanic is covering the cost of replacement?

 

Says he is, just hesitant to invoice till I have a final cost.


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Just wanted to follow up with everyone here and thank them for all of their suggestions.

My main concern was matching to my existing tail light which was still in pretty decent shape. After the grease treatment I soaked them again and gave them another round of the novus to prepare them for paint. But when they came out at the end they were looking pretty good and will match my existing perfectly.

Still going to test on the broken one, and if I get a good result, will treat both tail lights to hide the crazing.

In the meantime, here’s where I’m at:




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I had forgotten about tinting red to repair faded lens, I have always had kandy apple red on the shelf and have used that to tinted then clear cote. You can sand and buff or sand and re-clear for perfection. One added note the clear cote has UV protection so this is the last time you will need to F'k with the lens.
I use a 2k clear cote.

 

To do this, you have to have a 3-D (design) file for the lens first or have an existing lens scanned for point cloud data that could then be converted into .STL format for printing....

- EM

 

Just an add to the thread for general plastic restoration/cleaning, many older plastic parts contained additives for flame retardant, mold release, or processing aid that easily migrate to the surface over time making them look like hell. The ones exposed to the sun make it worse.
In these cases, a dilute hydrogen peroxide solution is usually the hot ticket to removing the additives that have leached to the surface without destroying the part. I have used this method on plastic gauge "glasses", knobs, vent parts, etc. with great success.
As always, try a small, obscure area first so you don't ruin your parts !

 

I clean with dish soap and then use............plastic polish .

 

I've got catalyzed primer overspray on some lenses (yeah, I know..). Will the usual chemicals, acetone, lacquer thinner, goop off, etc., melt the plastic?