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Products => Computers => Vintage Computing => Topic started by: TerraHertz on September 12, 2013, 02:55:32 pm

Title: Question - restoring sun-discoloured ABS plastic?
Post by: TerraHertz on September 12, 2013, 02:55:32 pm
A beige-coloured plastic case on something I'm cleaning up has some fairly noticeable yellowing due to sunlight exposure. It's particularly annoying where there were stickers, that left patches of the original lighter colour plastic.

Some people here seem to be wizards at restoring old equipment, so I wonder if anyone has any ideas for how to remove the yellowing? I can easily live with the staining if I can't find a way to fix it without risk of making the case look worse.

It's this: https://www.eevblog.com/forum/testgear/new-toy-tek-tla614-logic-analyzer/ (https://www.eevblog.com/forum/testgear/new-toy-tek-tla614-logic-analyzer/)
Title: Re: Question - restoring sun-discoloured ABS plastic?
Post by: krivx on September 12, 2013, 02:58:08 pm
The vintage computer crowd use Retr0Bright http://retr0bright.wikispaces.com/ (http://retr0bright.wikispaces.com/)

(http://www.vecchicomputer.com/wp-content/uploads/2010/04/Retr0Bright_Commodore64C.jpg)
Title: Re: Question - restoring sun-discoloured ABS plastic?
Post by: G7PSK on September 12, 2013, 03:05:14 pm
I have had some success with T-Cut which is a polish with a fine abrasive used in the car industry for buffing paintwork.
Title: Re: Question - restoring sun-discoloured ABS plastic?
Post by: robrenz on September 12, 2013, 03:36:17 pm
That retrobright looks like it works real well especially on textured surfaces. The yellowing on the buttons of my Tek 7603 restore came off with just a light wet sanding on 6 micron diamond film. Silicon carbide paper would work just as well. Then a polish with plastic polish will give the final shine. So if you have something that would be easy to sand and polish it may be worth a try. The discoloration on the Tek buttons seemed to be on the surface only.
Title: Re: Question - restoring sun-discoloured ABS plastic?
Post by: David_AVD on September 12, 2013, 09:04:04 pm
Some of the guys on the Aussie Arcade (http://www.aussiearcade.com.au) forum have cleaned up old gaming consoles with good results I believe.
Title: Re: Question - restoring sun-discoloured ABS plastic?
Post by: TerraHertz on September 13, 2013, 02:42:24 am
Retrobright - COOL! Thanks for the reference. Very interesting to read their work on the causes of the yellowing. I'd assumed it was due to UV-induced breakdown of the ABS plastic chains. But no....

Sanding is not an option since the surface has a fine texture, that I don't want to damage. Even just rubbing hard with a solvent-wet tissue to remove old sticker residue tends to 'shine' the surface in patches. The number of things I've put aside, waiting till I get around to setting up my big compressor and grit-blasting cabinet, grows.