Tail Light Lens Restore?

[rb1949]

Have the familiar problem with old tail light lenses ......... the "crazing" (crack marks) in the plastic lens, usually visible as those white lines You can't feel any crack on the outside nor the inside.The crazing seems to be inside the plastic. Searching finds multiple ways to correct faded lenses, but none address any procedures regarding the crazing issue.Has anyone ever come up with a way to remove, or hide, these white cracks? The lenses are in good shape, just cosmetically nasty looking. There is a web site touting a successful 'fix' for crazing, but the email or phone contact don't work. Tossing this out to the been there - done that forum members.

[Plymouthy Adams]

the 49 is the pits for bad lenses...not seen an actual good method to fix these but like you am always open to learn..there is a clear red for lenses marketed by Testor....not sure just how effective this is or if this is their process or part of the process.  I have some 49-52 Plymouth suburban lenses that suffer from the same ailments.  Do you have a website or other link that shows this process?  Or, is this a written ad without testimony?

[ptwothree]

I read an article a few years ago about using your old lens to make a mold to cast a new lens.  It's probably out there on the web some where......Look up 'plastic casting' or 'resin casting'.

[PT81Jan]

Have done such a repair at a motorcycles red tail lense by brushing an epoxy resin (not polyester!) to the inside of the lense. Warmed it then a little bit with a hair dryer to make it a bit thin liquid. This had the effect that the spider cracks soaked the epoxy. Of course it is not as perfect as a new one but not to see when two steps away. 

Edited November 13, 2016 by PT81Jan

[rb1949]

Yes, ample info on molding techniques. Don't think I would be successful at that. And places that will do it, no prices mentioned. Also spotted the epoxy trick which sounded interesting. No we're not looking for that perfect restoration, just make it look better. Will look for an old broken crazed lens for a test first.

[Reg Evans]

I wonder if this stuff would soak into the cracks and make them disappear.

https://www.amazon.com/Weld-Acrylic-Adhesive-Applicator-Bottle/dp/B0096TWKCW

[rb1949]

Experiments welcome. YOU try it! (always test on scrap pieces first). Description says: The bond is achieved by first softening the surfaces to be joined and then fusing them together with the dissipation of the solvent.

[Reg Evans]

46 minutes ago, rb1949 said:

Experiments welcome. YOU try it! (always test on scrap pieces first). Description says: The bond is achieved by first softening the surfaces to be joined and then fusing them together with the dissipation of the solvent.

If I had an old crazed lens I would be trying it right now. The #4 glue is the viscosity of water. I use to build aquariums out of acrylic and this glue would make the cloudy seams disappear.

[rb1949]

Darn, always a kink in the project. But read the Q&A on the site. One says do not use THIS product on aquariums. 

[Reg Evans]

My experience with it was in the mid 70's.  Did they also warn against using it on plastic tail light lenses ?

[lwebb]

I make reproduction lenses for vintage travel trailers and made reproductions of the tail light lenses for my 49 P18. It's a laborious process and not inexpensive. I'd be happy to share the process if anyone is interested. There was a lot of trial and much more error years ago when I started but I have a system which works for me. I use a vibrating platform,  a vacuum chamber that can take the materials down to 29 lbs, and pressure pot to take the material and mold back to 90 lbs while curing. The materials I use are latex molding rubber and a two part polymer that needs to be heated to 150º while in the pressure pot for 6-8 hours.

[PT81Jan]

Hey rb1949, I have a bit job experience with two suggestions of above. Every solution has its advantage and also disadvantage. 

Acrylic adhesive is quite easy to apply and gives a fairly good connection (smells terrible by the way). Obvious it is often thin like water,  it doesn't soak in smaller cracks that easy. Often the acrylic has lots of bubbles inside, warming up will inrease that effect. More recommended to glue two new pieces together that have a minimum split. 

Cast a new one is also possible,  but needs a bit experience to get a sufficient result. This would be a more sophisticated solution,  which I only would suggest, if there is no chance to find a spare part. If nevertheless of interest I would advise. (edit: while writing that Iwebb sent a better description. So I could advise, but I'm sure he would be your man!) 

That's the reason why I used the epoxy solution... 

 

Edited November 13, 2016 by PT81Jan

[Bingster]

You could try a water-base clearcoat tinted a translucent red.  There are other clear water-base polyurethanes used in cabinet finishing. Like painter's caulk, brush it into the cracks with a small detail brush and wait until it hardens a bit and wipe it off the lens in a circular motion.  You may have to repeat it until the crack is level with the rest of the lens surface.  It's kind of like when you are painting the lettering of a hub cap or some other chrome part where the lettering is stamped in relief.  You brush in the color, let it dry and wipe off the excess around the letters perimeter with rag lightly dampened with thinner.

Edited November 13, 2016 by Bingster
Thought of something else.

[rb1949]

lwebb, other crazed 49er's may be interested if you still have the mold. Is it an identical lens both sides? Mine are not. I'm sure they look great, but I dare not try it. Got a oix? The Epoxy method sound experimental yet and questionable. Would like to see some results.

Bingster: the crazing (cracks) are in the lens, but not felt on the surface. That's why I question how an Epoxy can fill/hide them.

And for Plymouthy, show and tell, using the Testors Transparent Red (4630). Looks nice parked, but the crazing is still there, quite visible when illuminated. Improved looks, but didn't solve the problem.

Where's the pix? Didn't mean to put links.

EDIT: just removed the links to pix. Tod fixed the problem and posted the pictures below. Thanks.

 

 

 

 

 

 

 

Edited November 13, 2016 by rb1949

[TodFitch]

52 minutes ago, rb1949 said:

Where's the pix? Didn't mean to put links..

Looks like the forum software got confused with the .a suffix and did not think they were images. I've downloaded them, renamed them to use a .jpg suffix. Lets see if they work this way.

[Plymouthy Adams]

The translucent red is the very stuff I mentioned above and marketed byTestors.  They do sell it in a 3oz aerosol can and the actual identification is 1605 Gloss Custom Red  

You should be able to find it at such stores as Michael's. Hobby Lobby or other arts and craft suppliers....if that fails....follow this link....

http://www.ebay.com/itm/Red-Spray-Testors-Enamel-Plastic-Model-Spray-Paint-/171749991655?hash=item27fd18e4e7:g:D5wAAOSwZQxW4kH9

Edited November 13, 2016 by Plymouthy Adams

[rb1949]

Yes Plymouthy you were mentioned in the above reply, posted just for you. This was the brush on bottle 4630. ($3.19) Very thin, but didn't flow into any 'cracks', so didn't solve the problem. Just went out in the dark to check, it glows pretty good, crazing visible. So the biggest benefit is a better looking lens in the daytime.

[Plymouthy Adams]

thanks...I have this stuff but not used it yet, got it to basically refresh a few reflectors........I also have given considerable thought to clearing the crazing if you will.....I am not convinced it is possible without some very special stuff along with a means of injecting the solvent through application of pressure...years ago I did some faux cloisonné repair with acrylics and acetone....that worked pretty well...

[PT81Jan]

Oops,  when your lense looks like the picture that ToddFitch has posted,  forget my Epoxy solution. Thought that the cracks ar not felt on the outside surface but on the inside.... 

Sorry

[rb1949]

PT, the pix are my rear lens project before and after. No problem, P-D members are great at coming up with ideas, and yours may be a benefit to someone.With close examination one can tell that the crazing cracks are not felt on the outside nor the inside, and form inside the plastic. Age, sun, weather, heat of the bulb. The paint was watery thin but did not creep into the cracks. Mentioned above, it does glow good in the dark but still has crazing. Yet a big daytime improvement in the looks of the lens.

Plymouthy, awaiting comments/pix of your test. A reflector might look OK to 'hide' crazing since it has no back illumination. But raises a question. What are the reflective properties of the paint? Maybe it would have none? Shine a light on a normal then painted one to see. Paint the backside Silver? This is getting interesting.

[Plymouthy Adams]

I am not working any lenses at the moment...bought my spray for faded out side reflectors on a little British car...

[rb1949]

But as questioned, what are the reflective qualities of a painted one? If only faded, buffing/polishing seems productive.

[Plymouthy Adams]

the prismatic cutting of the plastic backed by a foil substrate is the very reflective quality of the plastic reflectors....the spray was only to address faded/distressed coloring of aged plastic..not at all an attempt to make it reflective as this stuff has no properties in that regard..as to buffing a faded plastic reflector...pay close attention to the very Stimsolite reflectors that are part of the rear light bezel of the many cars of this era and show me how one can just buff color into an item that is void of color due to age and more than not UV breakdown...apples and oranges are getting comingled at this time regarding lens material/construction/application compared to that of reflectors..however the very translucent effect of the coating in the spray can will address both forms of plastic to a higher degree of uniform color...it is only a cosmetic approach and not a manner to make a lens as new...sort of like a woman and her facial makeup...except when it gets dark unlike the now unseen make up, the lens can afford you some protection.

 

Edited November 14, 2016 by Plymouthy Adams

[lwebb]

Hey rb49  I still have the mold but they are one of the biggest I've done and are dicey, Doable but harder than most. 

[rb1949]

Wow lwebb, great lenses and color. 100% better than old crazed ones. I compliment your effort and finished product. Only you could determine a price compared to buying NOS, if available. Keep up the good work on all your projects.