Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

revitalizing 40 year old plastic lenses

revitalizing 40 year old plastic lenses

revitalizing 40 year old plastic lenses

I've several plastic tail light lenses that used to be nearly unbreakable that are now down right brittle. Is there something I could soak them in to restore some of the resilience?

I figure I better ask before soaking them in a Tupperware container filled with Oil of Olay or neatsfoot oil.


Dan T

RE: revitalizing 40 year old plastic lenses

Some plastics, like PVC, contain plasticizers to soften them. Plasticizers are oily, high boiling, solvents that swell the plastic and make it rubbery rather than stiff. PVC pipe has no plasticizers while PVC upholstery in a car does. Plasticizers do slowly evaporate, so products like Armor All will restore the plasicizer. The plastic used in tail lights is probably polystyrene and it is getting brittle because the polymer is breaking down to lower molecular weight due to environmental oxidation (mainly due to sunlight). It cannot be restored.

RE: revitalizing 40 year old plastic lenses

Compositepro is right. Despite what the environmentalists are telling everyone, plastics readily break down.

Chris DeArmitt PhD FRSC

Plastic materials consultant to the Fortune 100
Creating New Materials - Problem Solving - Innovation Keynotes - Expert Witness

RE: revitalizing 40 year old plastic lenses

Here in he UK, tail light lenses were traditionally made from PMMA, which has excellent UV resistance as it is transparent to UV. Sounds like yours were possibly polycarbonate.


Politicians like to panic, they need activity. It is their substitute for achievement.

RE: revitalizing 40 year old plastic lenses

I think the problem is cutting of cross-links. Better start looking for new-old stock or reading up on making molds.

From this: http://read.nxtbook.com/wiley/plasticsengineering/... , if the plastic is not clouded then either UV driven chain scission or hydrolysis seem like they fit.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


White Paper - Reliability Verification for AI and ML Processors
Artificial intelligence and machine learning are seeing growing adoption in a wide range of applications. ICs used for AI/ML applications are characterized by large parallel processing computation units, high power dissipation, and complex circuitry that can deliver maximum performance within a strict power budget. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close