Cleaning printed brass tuning scale - UK Vintage Radio Repair and Restoration Discussion Forum

sentinel040 · 25th Mar 2013, 6:17 pm

I have been recently sorting out a discriminator fault on a GEC BC403, which had been aided and abetted by the phantom twiddler at some point in the past. Sometime last year I stripped the case and repainted the speaker grille etc and removed all the embellishments. At the edges of the front panel are (or were until I removed them) brass strips, a plain one each side to the outside and in-boards of that a printed one, with red letters or numbers on a plain brass background. The left hand side bears the tuning scale and station names and the right hand one the words "Tuning" and "Volume". The right hand one is not too bad but the left hand side is very badly tarnished - or should that be patinised.....

I have been considering this on and off - admittedly more off than on - for some time but cannot think of a way to clean the brass that will not risk damage to the red printing.

Another point is that there is some form of very localised corrosion, the appearance of which is a bit like rust spotting, but on brass.

Does anyone with experience of this sort of thing have any good ideas on how to clean these up?

Regards

Ian

brenellic2000 · 26th Mar 2013, 11:30 am

If the printing is by gold size then avoid solvents as they will lift it very quickly unless it has been well lacquered. Soapy water is probably best. Strictly speaking 'patina' applied only to copper carbonate 'oxide' on copper based alloys but has been widely mis-used to describe aging. OAP 'old aged patinas'... hmmmm!

TTFN

sentinel040 · 26th Mar 2013, 6:20 pm

Thank you for that.The printing is in red and must be fairly resilient to withstand daily wear and tear, the use of patina was supposedly tongue in cheek, taking the proverbial Michael if you like, but perhaps a little too subtle

. Some of he brass strips are very deeply discoloured, if it these had been lacquered it must have worn off, the fact that some have discoloured and others have not points to a late 50's / early 60's GEC quality control problem with the protective coating. It looks like there is little that can be done

If had been bits of a steam engine I would have thrown it in a bucket of Coke or for the really grubby bits old battery acid!

Cheers

Ian

brenellic2000 · 27th Mar 2013, 11:44 am

That is the major problem with lacquer - once applied it can be nightmare as once broken, it allows creeping oxidation underneath which needs the lacquering to be totally removed!

Has the brass been etched to receive the cliche printed lettering, or is it surface applied as if screen printed? If etched, it can be restored... but its labourious work!

Radio_Dave · 27th Mar 2013, 12:53 pm

I've just Googled some pictures of this radio and I'm not convinced it's brass. Have you tried a magnet on it to see if it's some sort of gilded steel?

David

RogerWalker · 27th Mar 2013, 1:04 pm

I have a similar problem with a etched/lacquered brass dials for the Cossor 343 ganging oscillator I'm restoring - see photos. Any advice on how best to restore these will be gratefully received.
Regards
Roger

sentinel040 · 27th Mar 2013, 10:07 pm

Brenellic2000, unfortunately (and my impending doom alarm is starting to sound) it is printed rather than etched. It is a rather cheap radio from the latter years of the valve era.

Dave, it is indeed non-ferrous, a check with a mag mount some time ago proved that point rather well.

Thank you for your helpful comments so far.

regards

Ian

brenellic2000 · 28th Mar 2013, 11:36 am

You may be lucky and still be able to find 'Letraset' (or its equivalent) in a suitable font, otherwise its a case of printing onto self-adhesive clear laser-film or transfer film.

Good luck!

25th Mar 2013, 6:17 pm	#1
sentinel040 Hexode Join Date: Feb 2007 Location: Near Lichfield, Staffordshire, UK, most of the time and Crystal Palace, S London, some of the time.. Posts: 330	Cleaning printed brass tuning scale I have been recently sorting out a discriminator fault on a GEC BC403, which had been aided and abetted by the phantom twiddler at some point in the past. Sometime last year I stripped the case and repainted the speaker grille etc and removed all the embellishments. At the edges of the front panel are (or were until I removed them) brass strips, a plain one each side to the outside and in-boards of that a printed one, with red letters or numbers on a plain brass background. The left hand side bears the tuning scale and station names and the right hand one the words "Tuning" and "Volume". The right hand one is not too bad but the left hand side is very badly tarnished - or should that be patinised..... I have been considering this on and off - admittedly more off than on - for some time but cannot think of a way to clean the brass that will not risk damage to the red printing. Another point is that there is some form of very localised corrosion, the appearance of which is a bit like rust spotting, but on brass. Does anyone with experience of this sort of thing have any good ideas on how to clean these up? Regards Ian

26th Mar 2013, 11:30 am	#2
brenellic2000 Octode Join Date: Aug 2006 Location: Rye, East Sussex, UK. Posts: 1,647	Re: Cleaning printed brass tuning scale If the printing is by gold size then avoid solvents as they will lift it very quickly unless it has been well lacquered. Soapy water is probably best. Strictly speaking 'patina' applied only to copper carbonate 'oxide' on copper based alloys but has been widely mis-used to describe aging. OAP 'old aged patinas'... hmmmm! TTFN

26th Mar 2013, 6:20 pm	#3
sentinel040 Hexode Join Date: Feb 2007 Location: Near Lichfield, Staffordshire, UK, most of the time and Crystal Palace, S London, some of the time.. Posts: 330	Re: Cleaning printed brass tuning scale Thank you for that.The printing is in red and must be fairly resilient to withstand daily wear and tear, the use of patina was supposedly tongue in cheek, taking the proverbial Michael if you like, but perhaps a little too subtle . Some of he brass strips are very deeply discoloured, if it these had been lacquered it must have worn off, the fact that some have discoloured and others have not points to a late 50's / early 60's GEC quality control problem with the protective coating. It looks like there is little that can be done If had been bits of a steam engine I would have thrown it in a bucket of Coke or for the really grubby bits old battery acid! Cheers Ian

27th Mar 2013, 11:44 am	#4
brenellic2000 Octode Join Date: Aug 2006 Location: Rye, East Sussex, UK. Posts: 1,647	Re: Cleaning printed brass tuning scale That is the major problem with lacquer - once applied it can be nightmare as once broken, it allows creeping oxidation underneath which needs the lacquering to be totally removed! Has the brass been etched to receive the cliche printed lettering, or is it surface applied as if screen printed? If etched, it can be restored... but its labourious work!

27th Mar 2013, 12:53 pm	#5
Radio_Dave Nonode Join Date: Jun 2004 Location: Norwich, Norfolk, UK. Posts: 2,543	Re: Cleaning printed brass tuning scale I've just Googled some pictures of this radio and I'm not convinced it's brass. Have you tried a magnet on it to see if it's some sort of gilded steel? David __________________ http://www.youtube.com/ My Nixie Clocks

27th Mar 2013, 1:04 pm	#6
RogerWalker Hexode Join Date: Sep 2005 Location: Powys, Mid-Wales, UK. Posts: 289	Re: Cleaning printed brass tuning scale I have a similar problem with a etched/lacquered brass dials for the Cossor 343 ganging oscillator I'm restoring - see photos. Any advice on how best to restore these will be gratefully received. Regards Roger Attached Thumbnails

27th Mar 2013, 10:07 pm	#7
sentinel040 Hexode Join Date: Feb 2007 Location: Near Lichfield, Staffordshire, UK, most of the time and Crystal Palace, S London, some of the time.. Posts: 330	Re: Cleaning printed brass tuning scale Brenellic2000, unfortunately (and my impending doom alarm is starting to sound) it is printed rather than etched. It is a rather cheap radio from the latter years of the valve era. Dave, it is indeed non-ferrous, a check with a mag mount some time ago proved that point rather well. Thank you for your helpful comments so far. regards Ian

28th Mar 2013, 11:36 am	#8
brenellic2000 Octode Join Date: Aug 2006 Location: Rye, East Sussex, UK. Posts: 1,647	Re: Cleaning printed brass tuning scale You may be lucky and still be able to find 'Letraset' (or its equivalent) in a suitable font, otherwise its a case of printing onto self-adhesive clear laser-film or transfer film. Good luck!