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 Post subject: German Radio Cabinets of the '50s-'60s
PostPosted: Nov Sat 01, 2008 5:42 pm 
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Location: Malone, New York USA
Hi-
Does anyone else regularly (or maybe at least seldom) perform complete strip-downs, repairs and refinishing of these cabinets along with restoring the brass and plastic trim?
I'd be happy to hear (see) of others successful experiences and hopefully learn of some tips I haven't discovered yet.

These radio cabinets seem to require a somewhat different approach and varied techniques than the typical '30s to '40s North American wooden models.
Oh, to be sure, the basics are the same, but I think there is a bit of difference regarding the replication of some of the "flamed" or polyester finishes and dealing with brass and plastic ornamentation.

I've read and saw a few of the projects performed by our European fellows on other sites, but don't recall reading of any posted here?


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 Post subject:
PostPosted: Nov Thu 13, 2008 3:43 am 
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Location: Navasota Texas
I think the super shiney mirror finish is called French Polish. Never tired it but know it's a shellac base of some sort. You might see if you can find an old book on refinishing, or look it up on line, to see how it's done.


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 Post subject:
PostPosted: Nov Thu 13, 2008 5:29 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Malone, New York USA
Hi-
French polished shellac is an entirely different finish from that deep, hard, high gloss finish found on some of the German radios of ca. 1957 and later vintage.

That finish found on German radio cabinets from the latter '50s to the earlier '60s is what some call "polyester lacquer," but is in reality a form of resin similar to that used in the top-coating of fiberglass.
It may be catalyzed, though I'm not certain of that, regarding this 50 year old finish.

I do know it is pretty when new, (shine sells, even then) and in vogue nonetheless, but has the all-too-common problem of developing stress cracks or splits and in worst cases, partial separation from the wood substrates.
I witnessed some of the consoles with this finish when they were relatively new (2-4 years old) and they had begun to develop stress cracking then.

This damage is largely due to the incomplete sealing of the relatively thin wood cabinets and the propensity of the wood to expand and contract due to variations or changes in the humidity and temperature levels of the environment in which they have been placed. The poly resin finish is too thin, stiff or hard to accept (comply with) the dimensional changes of the wood. Of course, direct physical stressing of the cabinets also results in this issue.

Knowing the delicate nature of this too-hard-for-its-own-good finish, I replicate it with multiple coats of nitrocellulose lacquer, each so-many coats being foam-block sanded with incremental grits to 2000 and then hand polished.

My first example at doing this had been just over ten years now, on a K├Ârting model 1047 that I since gave to my sister-in-law.
Since this example has been on display in the relatively stabile environment of her living room since, no splitting of the replica deep mirror "poly" finish has occured....So far, anyway.....
The good news is, that if some cracking or splitting were to occur, it can be repaired by re-melting new lacquer into the existing top coats and repeating the final steps of the process.

It is quite difficult (at least for me- and I haven't seen up-close and personal repair attempts by others that have made a believer out of me yet)-- to attempt invisible repairs to a badly cracked original poly finish...This is the reason I strip them completely and perform the procedure with the nitro lacquers.
I won't post photos of the finished examples on this forum since the last time I did show a completed project, it brought some of what I considered snide remarks, none of which had to do with other's perceived quality of the work performed.
I would privately share any of the procedures I use with those genuinely interested in trying a replica finish of their own.
I also hope that someone else, somewhere, can share their discoveries to expand my knowledge base on this topic.


Last edited by Dennis Daly on Nov Thu 13, 2008 7:10 pm, edited 1 time in total.

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 Post subject:
PostPosted: Nov Thu 13, 2008 5:48 pm 
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Location: Muscletown, USA
Those finishes can be quite striking. Very Shinney Larry-esgue. The Blaupunct that I received on eBay once, looked like it was NIB. Unfortunately, poor packing lead to a stress crack at every corner, Luckily I received a full refund ($135) and vowed to never have one of those beauties shipped. To recreate that finish would probably require you to follow Larry's instructions. For those radios, it would look correct :D


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 Post subject:
PostPosted: Nov Thu 13, 2008 7:24 pm 
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Location: Malone, New York USA
I don't know anything about "Shiny Larry" and his "instructions," though I've heard the name mentioned.
I'm not "required" to follow another's method to replicate the mentioned finish.
I altered the process I used to create automotive deep plano show paint jobs ala earlier DuPont paint systems. This works for me...."Da proof is in da puddin'."
....and yes....The transfer of skills and experience can work both ways.....


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 Post subject:
PostPosted: Nov Thu 13, 2008 8:29 pm 
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Have one Telefunken that has a couple stress lines. The finish looks likes its 20 thousanth thick. I don't know if stripper would touch that finish...


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 Post subject:
PostPosted: Nov Thu 13, 2008 9:55 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Malone, New York USA
MEK will affect some OEM German radio poly coatings to some degree, but you must place a covering over the top of the saturated material pads in order to retard the evaporation and enhance the fuming action (?) of the solvent.
I used aluminum foil to cover Bounty brand paper toweling folded into multi-layered saturated pads.
Not the best method for me.
Others may have alternative methods that work well?

I had tried lacquer thinners, acetone, methylene strippers, etc.
That OEM finish just laughed at them.

For overall stripping of a cabinet having this type finish, I now typically use a heat gun and a one inch putty knife.
One must be careful not to cause charring of the wood veneers.....Practice and continued caution makes for a job free of Uh-ohs.

There is a fine line between just sufficient heat to soften and assist in loosening the film and the excess of heat that will char the wood.

Start at an edge, keeping the heat gun ahead of the putty knife, get the poly to soften and allow lifting enough to insert the knife under the film.
Preheating the knife blade prior to starting the procedure helps a lot...
Continuously sweep the gun across and ahead of the intended direction of putty knife travel.
You'd be amazed how well the OEM finish lifts cleanly off the wood substrate once you have the 'hang of it.'
I have a single photo showing the heat stripping process on a Graetz Polka cabinet on my web page.
My last 'victim' was a Grundig 5490U/.

Certainly not inferring any chemistry knowledge here. I only know what has worked well (or not so well,)- for me. So far....


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 Post subject:
PostPosted: Nov Tue 18, 2008 10:47 pm 
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Joined: Sep Tue 09, 2008 10:15 pm
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Location: Manitou Springs, Colorado, USA
the polyester/lacquer finish is the same that's used on fender guitars.
.


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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Oct Fri 19, 2012 1:33 am 
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Joined: Sep Tue 18, 2012 8:25 pm
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I've done a lot of research on this topic on both German and English sites. I think the answer is truly going to depend on the year. I'm working on a 1954 Siemens Schatulle H42 right now, and that just has a lot of shellac on it. I've spent the day on the cabinet doors with Minwax Antique Furniture Refinisher and 0000 steel wool, and paper towels. It took awhile, but I got the coating off and the doors look beautiful. I still have to refinish them but the stripping process went fine.

I do know that in the latter 1950s and into the 1960s German manufacturers switched to "poly-lac", a polyester lacquer that was much thicker, harder and more plastic-like. Well, OK, technically it WAS plastic. I did see a similar type of resin lacquer at Home Depot that would probably be a great substitute for poly-lac but have no experience with it.


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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Oct Fri 19, 2012 4:05 pm 
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Location: Malone, New York USA
mboltz wrote:
I'm working on a 1954 Siemens Schatulle H42 right now, and that just has a lot of shellac on it.

Unless that radio was refinished in the past, the OEM finish was nitrocellulose lacquer.


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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Oct Fri 19, 2012 10:27 pm 
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Dennis -

You are correct, thanks for that. I had various things on the brain at that point regarding finishes and mistyped. Yes, it was nitrocellulose lacquer. And that's what it will be again, when I'm done.


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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Oct Sun 21, 2012 4:38 am 
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Location: Vermont, USA
Hello Dennis et al-

Getting back to the original subject of this thread, last Fall I stripped and refinished a big Grundig 5040 like this one-

Image

You might recall Dennis I got this a few years ago at an antique store in Whitehall cheaply. BUT the finish was utterly shot. Here it is on my table at Kutztown last Fall-

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It didn't sell so I determined to fix it up. I went at it with the traditional strippers to little effect. To my amazement Citrastrip covered with plastic film removed the finish cleanly in a couple of hours. I'm at a loss to explain why it would work when the tradtional stripper just dulled the finish but it bubbled it right up. Then I refinished with many coats of lacquer and sanding. The result is a decent appoximation of the original finish. The chassis should finally get recapped this winter. Missing trim I plan to mold and cast in epoxy.

John H.

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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Nov Mon 05, 2012 12:57 am 
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Joined: Sep Mon 07, 2009 8:56 pm
Posts: 11
Location: Germany & Philippines
Hi , a full cabinet restoration on these radios i guess its hardly to do for you in your home.
We do restore these radios totally back to factory cond.
I am allowed to post a link ? Not that we get anger here with the forum mods ? Just take a look for tuberadiodoc cabinet restoration
in ebay..we did post there examples of our works.

The 50s cabinets are finished in nitro varnish...BUT colored ..not with glaze or any other stuff...colored in the clear coat directly.
Then u will need a HS varnish ...many time...and many knowledge how to use the sandpaper works correctly.
After all a full polish like they did it in the 50s with a machine.

Nothing for to do at home ....just to spray the nitro varnish is not well for your health.

check out the youtube vid from us...
http://www.youtube.com/watch?v=kOV33o0RWWw
thats a Lorenz W52 fully restored and colored...for a lady from the states which wants give that beauty as xmas gift to her man...btw ..nice idea...
Looks original or ? :D We have also some pics from before ...if interested just write here ...i will read here from time to time ...
Note this was not resprayed..we did remove completely the old varnish on this cabinet...Excuse my english i hope u understand all well..

60s Radios.... Finished in polyesther.... From this procedure i guess some guys will agree there i can suggest only try not to do that at home.
Here in europe only companies like we are get this high class polyesther parafin varnish ... i dont know if u get that in the USA so easily in each store....
But to laquer polyesther you have to be careful..The 2C polyesther does a reaction and creates heat..this means it can come suddenly the big boom in ur garage or whereever u spray the cabinet.
To explain it better...Into the parafine u have primer again the color coat with nitro varnish.. but the finish is with parafin polyesther. But to note here..nitro and parafine polyesther is the dangerous couple..Did u understand my meaning in my baby english ?
Parafine polyesther is the finest varnish to finish wood ...reason : easy to tell...it has a high solid body content...u can polish and polish this varnish without to have afraid to burn it during the polish.
u cant remove polyesther varnish from the old 60s cabinets with a color remover...u will see it wont work...only with heat you can remove polyesther varnish.

Shellack polish or french polish is of course the most finest ...as some user wrote here...but not for a 50s radio cabinet, we use that method only for
art deco furnitures and older types of furniture. the most radios are finished in nitro and colored also in nitro.
use not acryl car varnish...this is from my view the kill of the history on and in the radio cabinet. And if u want to use an acryl varnish u must use only UHS
varnish. as u see the solid body content is very important to finish wood perfectly.
but its much more to note...the correct sandpaper works are also important ....I hope some infos could help you a bit
Greetungs Canete

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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Nov Fri 16, 2012 10:43 pm 
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Progress on my Siemens Schatulle H42 from 1954.

Using Minwax Antique Furniture Refinisher and 0000 steel wool, and lots of patience, after about a total of 8 hours of work for the disassembly, doors, and the full cabinet, I got all the original lacquer off.

I'm still deciding, since I never intend to sell this particular radio, whether I will go with this:
http://www.stewmac.com/shop/Finishing_s ... cquer.html

or whether I'll use a modern lacquer instead. I was also considering the Minwax lacquer, and then polishing in about 2 months after completion with SC Johnson's polishing wax for antique furniture.

Opinions and any comments on the work illustrated so far are welcome.


Attachments:
File comment: Partway through the front face, illustrating a good before/after contrast.
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File comment: front base after completion
IMG_2834.png
IMG_2834.png [ 130.77 KiB | Viewed 6091 times ]
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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Nov Fri 16, 2012 11:13 pm 
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Nitrocellulose film is soluble in acetone, but I don't know if that also applies to nitrocellulose-based lacquers as well. Unfortunately I don't have any enclosures that I can experiment with at the moment.


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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Nov Sat 17, 2012 12:16 am 
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markjd wrote:
Nitrocellulose film is soluble in acetone, but I don't know if that also applies to nitrocellulose-based lacquers as well. Unfortunately I don't have any enclosures that I can experiment with at the moment.


However acetone has zero effect on polyester finishes originally used on German radios.

John H.

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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Nov Sat 17, 2012 10:06 pm 
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True, but not all German radios used "Polylack". It became more prevalent in the latter 1950s. Before that, it was nitrocellulose. I think the bottom line recommendation should be to understand what the specific model/date used at that time.

With mine it was nitrocellulose, and it came off fine with the Minwax Antique Furniture Refinisher, which is a mixture of Acetone, Toulane, and something else.


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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Nov Sun 18, 2012 6:00 pm 
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Good point mboltz, perhaps my own Saba example wasn't actually polyester.

John H.

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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Dec Tue 24, 2019 3:34 pm 
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Location: Cedar Rapids, Iowa
I know this is a very old thread, but I want to thank those that contributed. I'm working on a Grundig SO202US that has that thick, shiny (when new) finish, and it's completely cracked. I tried Klean Strip and it had no affect. John H said he had success with Citrastrip so I tried that...no affect. So I tried the heat gun like Dennis Daly suggested and it worked great! When you get the finish to the proper temperature it literally just peels off. It can be difficult to get it started if you don't have any sections that are already missing, but once you do it's quite easy to remove.

Thanks!

Rich


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 Post subject: Re: German Radio Cabinets of the '50s-'60s
PostPosted: Dec Sat 28, 2019 5:44 pm 
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This might help you - -

https://www.russoldradios.com/blog/spectacular-saba

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