Identification Plate Restoration - UK Vintage Radio Repair and Restoration Discussion Forum

M0FYA Andy · 7th Apr 2009, 11:20 am

Folks,

Before I do anything and make a hash of it, I wonder if anyone has any advice on restoring the three plates, photo attached, which belong to a US Navy rack for an HRO receiver.

How were they made originally?

The letters and border stand proud of the background by a very small amount, I am wary that any abrasive method, after first spraying the whole thing, will simply end up with a shiny piece of metal with no letters left!

Many thanks,

Andy

Mike Phelan · 7th Apr 2009, 11:33 am

This might be of use, Andy.

M0FYA Andy · 7th Apr 2009, 11:59 am

Mike,
These plates aren't screen printed, they are 'three-dimesional', made out of quite heavy metal (1mm thick) which I think might be plated copper. The background is filled with paint, but the letters don't stand proud enough for me to want to simply dive in and paint them and then attempt to clean off the letters!

Andy

AlanBeckett · 7th Apr 2009, 12:04 pm

Andy,
They look to be 'Etched and Filled'. It is/was a popular process for mechanical equipement (lathes etc) which were subject to a lot of use and abuse, and also labels on Hazardous area equipment where they were supposed to survive an 'incident' (fire). The idea is to etch the surface, usually brass, aluminium or stainless, the fill the 'hole' up with paint. You could do it either way round - etch the background and let the characters show natural, or etch the characters and fill them with paint. You appear to have the former. Notionally, all you have to do is strip off the remaining paint, paint them, then gently sand off the high parts. The bad news is that it's already been done to yours, and there is probably also corrosion. The safest method is to remove any flaking paint then it's a keen eye, a steady hand and a small paint brush.
Alan

Mike Phelan · 8th Apr 2009, 8:38 am

Hmmm ... thinking aloud here, Andy. A few ideas.

Apply Letraset characters to use as a "resist". Spray it black and remove Letraset?
Make a new panel from copper sheet, do the Letraset thing and etch with ferric choride deep enough to spray background and polish letters off.
Same, but make it from aluminium alloy and etch with sodium hydroxide.

Aerodyne · 8th Apr 2009, 11:53 am

Neat ideas from Mike there, Andy. Another possibility: spray metal panel with photo-resist aerosol spray. Print out your computer-set lettering on film or on plain paper on a laser printer and spray the paper with WD40 to make it translucent. Withe the paper in contact with the resist surface, expose to UV light (sunlight) for a few minutes then etch the plate as detailed by Mike.
-Tony

M0FYA Andy · 8th Apr 2009, 1:05 pm

Mike, Tony,

A few interesting ideas there, many thanks!
An idea that has occured to me whilst assessing that the plates do seem to be nice and flat with a steel ruler, is (after cleaning off all the old paint with Nitromors if it hasn't been banned yet), spray over the whole plate, and then use the nice sharp edge of the ruler to scrape over the plates and hopefully only remove the paint from the raised letters. It is possible to just see light under the ruler in the background where the paint is to remain, so I'm optimistic. This might be more controlled than any abrasive method. As long as I don't scrape too vigorously and remove metal!
Andy

Aerodyne · 8th Apr 2009, 3:38 pm

Since posting my suggestion I've found the following link that might interest you:

http://www.rideonrailways.co.uk/page8.html

-Tony

JHGibson · 8th Apr 2009, 5:05 pm

Andy,
Let us know if you come up with a successful solution!
John.

GeorgSc · 8th Apr 2009, 6:14 pm

Quote:

Originally Posted by M0FYA Andy

Mike, Tony,
... then use the nice sharp edge of the ruler to scrape over the plates and hopefully only remove the paint from the raised letters. It is possible to just see light under the ruler in the background where the paint is to remain, so I'm optimistic.
Andy

Hello,
thats the way those plates were made originally.
The ruler is called a "blade" often "doctor blade" or short "doctor".
I repaired a similar, but much smaller plate in the way you described,
the differnce was, that I waited until the laquer was nearly dry
and used a rod of aluminium oxide (from a Pt100) as a doctor.
The rod had a diameter of about 8 mm and polished the brass
plate at the same time.
(Similar to a polish by a hard steel sphere)
Georg

georgesgiralt · 9th Apr 2009, 9:46 am

Hi !
I've done repaint on such letters. (not on radio equipment, though).
I've chemicaly stripped all paint. Then I've painted the whole in black using a spray.
When dry, I took my one hair brush and painted white the letters. Result was perfect.
I used a small Humbro white paint used for models. Fast to dry, brush strokes don't show too much. But you've to had a steady hand to get the job done....

7th Apr 2009, 11:20 am	#1
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	Identification Plate Restoration Folks, Before I do anything and make a hash of it, I wonder if anyone has any advice on restoring the three plates, photo attached, which belong to a US Navy rack for an HRO receiver. How were they made originally? The letters and border stand proud of the background by a very small amount, I am wary that any abrasive method, after first spraying the whole thing, will simply end up with a shiny piece of metal with no letters left! Many thanks, Andy Attached Thumbnails

7th Apr 2009, 11:33 am	#2
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Identification Plate Restoration This might be of use, Andy. __________________ Mike.

7th Apr 2009, 11:59 am	#3
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	Re: Identification Plate Restoration Mike, These plates aren't screen printed, they are 'three-dimesional', made out of quite heavy metal (1mm thick) which I think might be plated copper. The background is filled with paint, but the letters don't stand proud enough for me to want to simply dive in and paint them and then attempt to clean off the letters! Andy

7th Apr 2009, 12:04 pm	#4
AlanBeckett Rest in Peace Join Date: Dec 2008 Location: Burton upon Trent, East Staffordshire, UK. Posts: 1,686	Re: Identification Plate Restoration Andy, They look to be 'Etched and Filled'. It is/was a popular process for mechanical equipement (lathes etc) which were subject to a lot of use and abuse, and also labels on Hazardous area equipment where they were supposed to survive an 'incident' (fire). The idea is to etch the surface, usually brass, aluminium or stainless, the fill the 'hole' up with paint. You could do it either way round - etch the background and let the characters show natural, or etch the characters and fill them with paint. You appear to have the former. Notionally, all you have to do is strip off the remaining paint, paint them, then gently sand off the high parts. The bad news is that it's already been done to yours, and there is probably also corrosion. The safest method is to remove any flaking paint then it's a keen eye, a steady hand and a small paint brush. Alan

8th Apr 2009, 8:38 am	#5
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Identification Plate Restoration Hmmm ... thinking aloud here, Andy. A few ideas. Apply Letraset characters to use as a "resist". Spray it black and remove Letraset? Make a new panel from copper sheet, do the Letraset thing and etch with ferric choride deep enough to spray background and polish letters off. Same, but make it from aluminium alloy and etch with sodium hydroxide. __________________ Mike.

8th Apr 2009, 11:53 am	#6
Aerodyne Octode Join Date: Jun 2004 Location: Hampton Vale, Peterborough, UK. Posts: 1,698	Re: Identification Plate Restoration Neat ideas from Mike there, Andy. Another possibility: spray metal panel with photo-resist aerosol spray. Print out your computer-set lettering on film or on plain paper on a laser printer and spray the paper with WD40 to make it translucent. Withe the paper in contact with the resist surface, expose to UV light (sunlight) for a few minutes then etch the plate as detailed by Mike. -Tony

8th Apr 2009, 1:05 pm	#7
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	Re: Identification Plate Restoration Mike, Tony, A few interesting ideas there, many thanks! An idea that has occured to me whilst assessing that the plates do seem to be nice and flat with a steel ruler, is (after cleaning off all the old paint with Nitromors if it hasn't been banned yet), spray over the whole plate, and then use the nice sharp edge of the ruler to scrape over the plates and hopefully only remove the paint from the raised letters. It is possible to just see light under the ruler in the background where the paint is to remain, so I'm optimistic. This might be more controlled than any abrasive method. As long as I don't scrape too vigorously and remove metal! Andy

8th Apr 2009, 3:38 pm	#8
Aerodyne Octode Join Date: Jun 2004 Location: Hampton Vale, Peterborough, UK. Posts: 1,698	Re: Identification Plate Restoration Since posting my suggestion I've found the following link that might interest you: http://www.rideonrailways.co.uk/page8.html -Tony

8th Apr 2009, 5:05 pm	#9
JHGibson Retired Dormant Member Join Date: Apr 2003 Location: Salt Spring Island, BC, Canada Posts: 368	Re: Identification Plate Restoration Andy, Let us know if you come up with a successful solution! John.

9th Apr 2009, 9:46 am	#11
georgesgiralt Hexode Join Date: Jul 2008 Location: Toulouse, France Posts: 406	Re: Identification Plate Restoration Hi ! I've done repaint on such letters. (not on radio equipment, though). I've chemicaly stripped all paint. Then I've painted the whole in black using a spray. When dry, I took my one hair brush and painted white the letters. Result was perfect. I used a small Humbro white paint used for models. Fast to dry, brush strokes don't show too much. But you've to had a steady hand to get the job done....