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How to remove scratches from "plastic" phones?

Started by xtal_01, March 18, 2023, 10:02:03 PM

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xtal_01

I have a Leich 905 (or 105 .. case case) ... that has a cracked case.

I see a few cases on ebay  but they are in rough shape ... lots of scratches.

I hear people talk about Novus but have never tried to polish plastics (well Bakelite but this very hard.  The case is thermoplastic (according to the 1953 catalog).

Is it hard to polish soft plastic or ?

Any advice?

Thanks!

TelePlay

I posted this topic on removing scratches from soft plastic (which is easier that removing scratches from hard (ABS) plastic.

http://www.classicrotaryphones.com/forum/index.php?topic=20164.0

And there are many more successful scratch removal posts on this restoration board.

http://www.classicrotaryphones.com/forum/index.php?board=24.0

And, both soft and hard plastics are "thermoplastics." The chemical composition of the plastic makes it a hard or soft plastic.

xtal_01

Exactly the information I was looking for!

Question .... do I consider a Leich 700 shell soft plastic? 

It is very flexible ... the 1953 brochure in the library says it is "thermoplastic"  ... but does that make it soft plastic?

Would it be the same as the WE 302 or ?

Thanks!

TelePlay

Quote from: xtal_01 on March 19, 2023, 12:07:49 AMQuestion .... do I consider a Leich 700 shell soft plastic? 

There a two quick tests.

Does it smell like bad cheese? Then it's Tenite soft plastic.

A more exact test is a chemical test. Put a small drop of isopropyl alcohol (use a wooden toothpick to place the drop on the plastic) inside the housing and let it dry by itself. If it is soft plastic, it will leave a small circle where the drop was placed. If it is hard plastic (ABS), the plastic will not be affected, no circle will appear.

This is why it is much easier to remove scratches from soft plastic, isopropyl alcohol nicely and slightly dissolves soft plastic (start with a 50-50% solution of alcohol and water and increase the alcohol percentage until it begins to work on the plastic).

There are more than a few topics about making soft plastic shine that use isopropyl alcohol as the cutting agent with a variety of cloths. After getting the scratches out with alcohol, Novus 3 and then Novus 2 will create a very nice finished shine.

If you have never done this before, go slow to develop your learning curve for this kind of restoration. Don't rush it. Watch what each of your attempts does to the plastic and adjust as you go. You really can't hurt the plastic for any "ooops" moments can be sanded off with 400 or 600 grit paper and then begin the chemical polishing on the sanded area.

None of this applies to Bakelite which is a much different type of thermo setting material that is chemical resistant.

xtal_01

Awesome!

Thanks so very much for all the information!!!

I have been lucky up till now ... all my older phones were metal or Bakelite.

I was just a bit concerned with I got a few that were a softer plastic.

I will definitely give it a try!

Mike