How to re-create small plastic screen from 90's car radio?

I'm rehabbing a radio from a 1992 Acura NSX. Most of the issues are gone after replacing 80+ capacitors and performing some trace repair, but there is one thing that is still a problem. This translucent screen has warped slightly over time and is now pressing against one of the circuit boards, causing issues with a couple of the buttons on the faceplate.

Does anybody know how to remanufacture one of these? The mix of tight tolerances and clear plastic has me stumped.

Alternatively, does anybody know enough about plastics to say that heating it to XXX degrees would take the warp out of it?

I would imagine that a laser cutter would make a shape like that fairly easily.  You need to find the right material though, some plastics produce toxic fumes when cut with a laser.

There are online places where you can submit a CAD file and your credit card and they'll laser cut it and mail it to you.

That's tough and would indeed be difficult to have remade on a non-industrial scale.

I've managed to reshape warped plastic before with extremely careful use of a heat gun but I wouldn't try that until you are sure you have zero other options.

My half-formed thought is to wrap it in something and put it in the oven with some weight on it to straighten it.

Try progressively warmer water to heat the plastic.

Clamp it between two pieces of steel and gradually heat it up. 

Interesting.  I have no idea how to recreate one.

When modern slot car chassis are warped the answer clamp the chassis to a steel plate with magnets, put the steel plate in a tray of water covering the part and heat it in an oven.

Try at your own risk.   Slot car chassis are neither clear or decorative.

2nd idea, maybe buy a used non-working unit for the part.

In reply to Noddaz :

Good call. Being that the NSX is a Honda, can you get ahold of a junk stereo from a similar year Civic or Accord and test on that lens?

Appleseed said:

In reply to Noddaz :

Good call. Being that the NSX is a Honda, can you get ahold of a junk stereo from a similar year Civic or Accord and test on that lens?

This is what I was thinking as well.

Thanks all!

The radio itself doesn't fit any other models, but I have no idea if Honda would have been buying say, civic radios, from Alpine during that period, or if they had a similar clear plastic lens.

I'm comfortable doing some destructive testing on this piece though as it's not usable in it's current form. 

The plan is to clamp it with some pieces of flat steel and stick it in a sous vide bath for a while. 

Any guesses on what temp and for how long?

CrustyRedXpress said:

The plan is to clamp it with some pieces of flat steel and stick it in a sous vide bath for a while. 

Any guesses on what temp and for how long?

Temperature 135°F for medium rare. Based on the thickness, i would say it shouldn't take more than a few minutes, but i am basing my information on steak so your results may vary, and be less tasty. 

It's unlikely it was exposed to temperatures above 130 in the car when it bent the first time, so I'd start low ands work up. 

Im guessing it's very likely cast acrylic. 

I would lightly clamp it between two pieces of wood and leave it out in the sun for a while. Depending on location, warm sun may be hard to find...

I would try something like this & just modify the process as-needed based on the size and shape of the part you're working with.

https://www.youtube.com/watch?v=ljRaBiZLtGk

Awesome. I was going to say you can very accurately control the temperature with a sous vide, but I didn't mention it since not everyone has one of those..

Assuming it's acrylic plastic (Plexiglass), the melting point is 320 °F (160 °C)  but i wouldn't heat it anywhere close to that.  Perhaps you could hold it for a few seconds over a pot of boiling water, or the steam from a teapot, and see how that works.  The thing about clamping it between two pieces of wood or metal is it may take on a texture from the mating surfaces.

Could you just make a mold and cast one out of epoxy or acrylic

Do you have a picture of what those radios look like? I have a few old Honda radios sitting in my attic from that era. No idea what models they are from as I accumulated them over the years of working at Honda/Acura. I might have an extra for you.

Also the warm water method would be my first go to. Followed by the hot sun and having it sandwiched between two steel plates or something similar. Lastly I would laser scan it to a cad program and have someone try to recreate it for you. 

I expect it will get less clear with heat. I would poke around at rapid prototyping places. It will cost you, but the curve is going to be difficult to otherwise replicate without waves.

See pic of radio below, but if you have one don't give it away =)

I'll give 130F a shot on the sous vide, maybe try 15 mins, then 30, then an hour. I like that method because somebody else has an exact way to replicate the "repair" in the future. If possible I'll use glass to try and avoid marring the surface too badly.

Making a mold and casting in epoxy is something I thought of, but at some point I'd still have to deal with the issue of the warpage, even in a new part.

Hope to have an update this weekend.