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THE AM BULLETIN BOARD => Technical Forum => Topic started by: WBear2GCR on June 14, 2019, 02:10:04 PM



Title: YELLOWED Collins Dial Drums - Guess What!
Post by: WBear2GCR on June 14, 2019, 02:10:04 PM

Working on refurbishing some Collins R-388 receivers. Which are coming out great...
A few will be available to acquire shortly. (contact me if ur interested in more info)

SO, I have a dial overlay, and thought I'd try one.

Let's clean the old dial drum first.
What to use?
Ok. Rubbing Alcohol... why not?

Hey, look the surface is getting sticky!!

Guess what it's SHELLAC!

As far as I can tell, it is shellac, which explains why it yellows so much
over time... unfortunately the printing itself is not a particularly good ink,
so it comes off just fine with alcohol or most other things...

But this explains it.

                               _-_-bear

 


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: KB5MD on June 14, 2019, 02:26:49 PM
That yellowing on a Collins dial can be alleviated by spraying with common laundry bleach.  I have used this method on a couple of the old drum dials like the  75A4 with good results.
I don't think it will work on Hallicrafters dials though since they screened their dials with a water based paint.


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: WBear2GCR on June 14, 2019, 02:30:57 PM
Really?

Diluted?
Full strength?

What about runs???


Removed from the rig first??

What sort of results did you get?? (pix??)


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: nq5t on June 14, 2019, 03:16:12 PM
For the few bucks it costs to buy and install a good quality replacement overlay, It's probably not worth dragging out the bottle of Tilex (or whatever) to see what happens


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: KK4YY on June 14, 2019, 03:50:37 PM
How about using a complementary colored blue bulb behind the yellow dial?

Wait, what?


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: W3RSW on June 14, 2019, 08:35:42 PM
probably end up with dirty, dull brownish green.  ;D 
-Green for the blend. Brown from what's already aged.

There's a difference between spectrally additive and artist's blend.
Best Scotch that is. Single malt.


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: KK4YY on June 14, 2019, 09:41:56 PM
Rick,

I'll have to take you word for it... the Scotch, that is. Unless Jim Beam runs out of bourbon. ;D


Don


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: KB5MD on June 14, 2019, 11:53:29 PM
The bleach is applied with a Q-tip, thus, no runs.  Use bleach full strength and let dry.  You will begin to see the difference quickly.  No need to remove from radio to apply.
The same thing can be done to ceiling tile that has water marks from a leaking roof.


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: KA0HCP on June 15, 2019, 11:05:00 AM
Bleach?  Insane!

I clean dials with either Novus Polish system, #1 and #2 or with Flitz polish, using Q-tips.  I avoid touching the lettering itself.  Too easy for it to disappear in a flash. 


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: WBear2GCR on June 15, 2019, 10:18:20 PM
Novus polish on a Collins drum??
Wrong stuff on the wrong material... it's not plastic.
Not the bezel, the drum that has the Mc displayed... the bands?


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: WBear2GCR on June 15, 2019, 10:20:24 PM
KB5MB... so is it Q-tips or spray?

Got any pix showing before and after??


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: KC4VWU on June 16, 2019, 06:24:34 AM
Really? Come on Bear, tighten up! That's old news!

Just kidding. A little while back when I had listed a 75A3 for sale, someone who had responded made a comment about the "yellowed" Mc. dial in comparison to the white Kc. dial. Yep, sadly enough that is true, but I explained to him that EVERY factory Collins Mc. drum dial on the 75 and 51J series would be yellowed by now because they were a paper label and coated at the factory to protect them. I told him lacquer, but it may well be shellac. My quick thought process behind my presumption was envisioning those lovely golden brown lacquered maple necks on the Strat's and Tele's from that era. Not only that, but just the feel of it and closely looking at the bare drum edges will kind of confirm that they were coated


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: WBear2GCR on June 16, 2019, 08:30:44 AM
Shellac is the key to it.
That's new, never seen it mentioned before.
Knowing the coating means that one can deal with it appropriately, and not
have to guess.

Lacquer might have yellowed, but not the the extent that some of these dial drums do.
At least based on what one sees with vintage nitrocellulose guitar lacquer finishes,
I think this is likely correct (the yellowing part).

Alright then? :D


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: KC4VWU on June 16, 2019, 03:26:33 PM
Well, I don't know now. I did a search on shellac and found this;
 http://www.madehow.com/Volume-4/Shellac.html

Says in text that shellac does not oxidize. So does that mean it does not yellow? Hard to believe, because the house I grew up in had knotty pine paneling walls in the kitchen and hallway. My grandpa had to replace one of the panels at one point after the house was about 25 years old. The paneling was already a dark amber color, and the piece he replaced stuck out like a sore thumb because it was so white! After about 10 years, you couldn't tell it was a replacement panel from the rest. All the panels were shellac'd.

Anyways, glad to learn that shellac is made from bug secretions.  


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: WBear2GCR on June 16, 2019, 10:54:09 PM
I've got no clue what they mean by does not oxidize.

It certainly yellows, darkens and eventually becomes very dark...
Also it comes in different "grades" and colors when new.

Actually it is the bodies of the Lac Beetle, afaik. Maybe the wings...
don't recall.

Sometimes it crazes sort of like wrinkle finish...


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: KA0HCP on June 17, 2019, 09:39:35 AM
Novus polish on a Collins drum??
Wrong stuff on the wrong material... it's not plastic.
Not the bezel, the drum that has the Mc displayed... the bands?
I'm not familiar with Collins equipment; merely offering experience with with my radios.  Novus #1, is a cleaning solution with no abrasive component, and is good for cleaning any surface.  Certainly much safer than bleach. ;)


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: WBear2GCR on June 17, 2019, 10:20:24 AM
This image might help visualize what we're speaking of...

Usually, they're much more yellowed and unevenly so.


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: ka8gef on June 18, 2019, 08:07:21 AM

I know the conversation has focused on the dial drums...has anyone had experience with the 75A series (i.e. 75A-2) kilocycle dial?

After restoring my 75A-2, I stored it on a work shelf, facing westward for several months (unused room). The daily late afternoon sun slipped though the blinds and caused the exposed portion in the dial window to brown. duh....

Of course it had to be the AM window on 40 meters. ('85 to '00) and it is truly annoying.

Any success/advice in addressing this or am I up against a reproduction from the few out there that offer these replacements (Radio Daze, Howard Mills)?

Thanks

ka8gef






Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: WBear2GCR on June 18, 2019, 01:16:29 PM
The sun turned it brown?
Hmmm... I always saw that browning as being caused by the pilot light
bulb being in the same location forever...

I'd go for a repro, or one off epay...

                       _-_-bear


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: ka8gef on June 19, 2019, 09:29:33 PM
A relatively brief (perhaps 30 minutes) direct beam of sunlight through open blinds, everyday for about 18 months....it surprised me as well...ka8gef


Title: Re: YELLOWED Collins Dial Drums - Guess What!
Post by: Opcom on June 20, 2019, 01:00:05 AM
One period of exposure to the above light has been known to melt the plastic lenses at the faces of CRTs in the old school 3-CRT video projectors. Never underestimate old King  Sol.
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