Colour Restoring: Siemens Centenary Neophone

[FABphones]

Today I started work on a Siemens Neophone.

I always thought these were ABS so I was all geared up for a session of chemical sanding with Acetone and Meths. However, Acetone does nothing to the surface of this phone. So this phone is Tenite or soft plastic? Are these one and the same?

I've looked up a few chemical sanding threads. Lots of good info, I just need to identify what I have. The only info I can find re the manufacture of the Neophone says 'moulded in impact resisting polystyrene'. If correct, what chemical sanding method category would that fall into?

Any pointers appreciated. Thanks.

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Additional Edit - Photo of Siemens Centenary Neophone:

[Owain]

originally moulded in black Bakelite but, shortly after its production, urea formaldehyde plastics

https://www.britishtelephones.com/neophon.htm

[FABphones]

Thanks for the reply, it is the other Siemens Neophone (Horseshoe), Centenary Neophone..

https://www.britishtelephones.com/siemensb/cenneo.htm

[Owain]

Maybe pure polystyrene rather than an ABS co-polymer.

[KaiserFrazer67]

I'm a little surprised that the polystyrene plastic wasn't affected by the acetone.  Polystyrene, IIRC, is the same kind of plastic from which plastic models (cars, planes, model trains, etc.) are made.  Acetone usually softens that stuff up like water on sugar.

[LarryInMichigan]

The plastic is very light and brittle.  It is definitely not ABS, but it doesn't feel quite like polystyrene either.  It sure cracks easily.

Larry

[twocvbloke]

If it's this stuff, then I can see why it cracks easily:

https://www.bpf.co.uk/plastipedia/polymers/HIPS.aspx

Squishing a plastic cup often results in the stuff cracking...

[FABphones]

Very possibly, a 1961 version of.

*Added screenshot from above link for future reference.

[andy1702]

If it's polystyrene then (if I'm remembering my railway modelling days correctly) MEK should disolve it in a similar way to how acetone disolves ABS. MEK is the main ingredient in 'Plastic Weld', a product modellers in the UK have been using for years to assemble plastic kits without glue. It just melts the surface of the parts to be put together.

More about MEK here: https://www.americanchemistry.com/MEK/

[FABphones]

If it's polystyrene then (if I'm remembering my railway modelling days correctly) MEK should disolve it in a similar way to how acetone disolves ABS. MEK is the main ingredient in 'Plastic Weld', a product modellers in the UK have been using for years to assemble plastic kits without glue. It just melts the surface of the parts to be put together.

More about MEK here: https://www.americanchemistry.com/MEK/

Arghh!!!! I have a bottle of MEK right next to the Acetone. I will be trying that out tomorrow...

So far I have spent over 15 hours sanding this phone by hand. Ouch.

Before and after photos of progress so far:

[FABphones]

...and here it is next to another one I have yet to do.

As you can see both of these have the optional extra Dial Surround riveted on. Not many had these and as they are riveted to the phone, that, coupled with the phones manufacturer mark on the rear, meant bleaching was out of the question. Hence the need to sand. Did I mention Ouch...

[RB]

Yup, arduous work to be sure...
But, looks good 

[andy1702]

Did the MEK work?

[FABphones]

Did the MEK work?

The second phone has moved a little down the 'to do' list. Various reasons, the main one is ventilation. The work area I currently use has very little, so now the warmer weather is here I'm organising myself a small workshop in one of the outbuildings. Lots of ventilation and natural light.