Author Topic: Repro glass dial scale for a Hallicrafters S-38D?  (Read 3802 times)

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Offline kmm

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Repro glass dial scale for a Hallicrafters S-38D?
« on: April 06, 2016, 08:25:10 pm »
After an orgy of watching Mr. Carlson restore tube radios on youtube, I picked up a Hallicrafters S-38D on ebay to restore for myself.

It was in pretty good condition until the seller wrapped it in a couple layers of foam and paper :palm: and apparently space jam slam-dunked it into the mail bin. As received, both glass pieces of the tuning dial are completely smashed, which is particularly disappointing because I have no idea where to get another one aside from a donor radio that will probably cost as much or more than I paid for this one.

I did some cursory googling but I'm not finding anyone making screenprint glass repros of these. However, this is my first tube radio resto so I don't really have a good list of niche suppliers that might produce such things, and I may not even be using the right phrasing in searches. If anyone has any pointers that would be great.

Failing that, has anyone done their own screenprinted glass reproduction dials? This sounds like the easiest way to me to get an accurate copy, but I'm kinda dreading drawing up a properly proportioned 1:1 vector of the scale based on the jigsaw puzzle of broken pieces I have. If anyone has already done this before and has artwork suitable for making a printing screen from it would be really helpful.

The silvery pleathery-paper material that serves as the dial background was also damaged by the glass fragments, does anyone know what it's called and if something similar is still available, or should I just hit up the fabric/craft store and find something approximate?

As a general aside,  the little strings that operate the bandspread and tuning machinery were severed by the glass. What sort of pain-in-the-ass-factor can I expect here when it comes to re-stringing and re-aligning? I have a couple good meters, a couple good scopes, and a crappy DDS signal generator, but no service monitor or spectrum analyzer/tracking generator.
 

Offline PaulAm

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Re: Repro glass dial scale for a Hallicrafters S-38D?
« Reply #1 on: April 06, 2016, 10:23:32 pm »
You need to go to the forums on antiqueradios.com.  Lots of expertise and suppliers for exactly that kind of problem.  People also sell and trade parts, so you might get lucky there.
 
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Offline kmm

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Re: Repro glass dial scale for a Hallicrafters S-38D?
« Reply #2 on: April 07, 2016, 02:11:19 am »
Looks like a good place to start, thanks!
 

Offline AF6LJ

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Sue AF6LJ
Test Equipment Addict, And Proud Of It.
 
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Offline kmm

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Re: Repro glass dial scale for a Hallicrafters S-38D?
« Reply #4 on: May 02, 2016, 04:28:13 am »
Here's some pics of the work I've done, in case anyone is interested in this sort of thing.

The recommendations were great, reading a few threads on the AntiqueRadios forums and putting in an order to Radio Daze pretty much solved all my problems.

TRIGGER WARNING - this is a "restomod" of a pretty busted up radio. Purists should stop here, there's HERESY ahead.  ;)

This radio was pretty smashed when I got it, and the original paint and graphics were only in passable condition before the shipping damage:


But the guts looked ok, and hadn't been rusted or hacked up to any major extent.
The bandspread dial cord was severed in transit, and the others were weak with dry rot. All were replaced.


Vintage tubes, vintage grime, probably some vintage rat shit just for extra flavor:


Underside wasn't bad, but was full of somewhat greasy gunky residue, some of which had polymerized and hardened over time and heat. I suspect the big quad-electrolytic that originally was clamped in by that ring blew it's load all over some time in the distant past.
I replaced all the crusty electrolytics and waxies before even applying power, as I don't have a convenient or safe variac to isolator setup right now.
I don't have a shot of it untouched, but this is right after I replaced the electrolytic with modern, good quality caps.


One last shot of the original paint. This radio is ca. 1954, so it had more than fulfilled its service life:


Chemical stripper is somewhat unfriendly and generally pretty gross to work with and I didn't have any on hand anyway.
Mister wire wheel made short work of the old finish:


First time anyone has seen this enclosure naked since my parents were kids, Bill Haley was rocking around the clock, and we were lighting off nukes in some tropical paradise just for fun. Come on, you know it had to be fun setting that stuff up and watching it go off.


Primed in my professional paint booth:


No shots of painting process because getting paint right requires my full attention...this was attempt #2.
I mixed up the base coat from hardware store enamel, mostly black and hunter green, with a half a bee's dick worth of silver and dichroic pigments to give a very subtle sparkle. Thinned it way way down with xylene (or if you want to be precise, mixed dimethylbenzene isomers...) and applied lots of light coats in succession. On top of that there's a few coats of urethane, with the first also having a tiny speck of dichroic pigment for a bit of depth.
Applied in a makeshift tent outside with a $13.99 Harbor Fright touch-up gun, wet sanded and polished with elbow grease for a showroom shine.

Color turned out a nice shade of very mildly metallic British racing green, which I was quite happy with.


Rubbed the chassis lightly with steel wool to get rid of the oxidation, cleaned the tubes up with ethanol. All the tubes are original (as received at least) except the 12SG7 that made the trip bouncing around in the enclosure and arrived with a little piece of broken glass rattling around inside it.


Finished electrical repairs and mods. This radio came from the factory with the power switch on the neutral leg. My intent for this is to sit in my living room as a functional decoration, so I wanted it to be reasonably safe. I replaced the shitty 70s lamp cord with less shitty modern polarized lamp cord, moved the switch to the hot leg, and added a 1A inline fuse. I haven't fully electrically isolated the chassis from the enclosure yet, but I plan to when I take it apart again to put on the final coats of urethane.
I had to bodge a couple caps to get into the right ballpark with the cap values I had on hand, not sure if I'll bother going back later to replace em with more proper caps since the performance is fine. The line cap however will be replaced with a class X rated cap as soon as they arrive.


Speaking of electrical isolation, one of the little hard rubber standoffs was missing and replaced with a "washer" hand cut from a scrap of plastic. I made a mold of one of the originals, and cast a replacement in epoxy resin. The clear one was a test to see if the mold was usable, the one clockwise and down is the mold model, and the one to the left of that is the copy. Same epoxy, just colored with lampblack gathered from a candle (it's not appreciably conductive, despite containing enough carbon to make it deep obsidian black).


Probing around the LO and mixer bits for fun and future plans; scope is displaying country music beamed from Navajo country in New Mexico, a couple hundred miles south of me. Not bad for 30 feet of wire taped to the wall.


Almost done. I replaced the damaged backing material with high quality white paper, I think it actually looks better than stock this way.
The decals were water transfer type that I got from Radio Daze. I haven't used these things since I was a 13 year old making model airplanes; they're just as tedious to apply now as they were then.
I never knew the substrate material was alcohol soluble, while the letters are not. Once it's dry (and COOL, as you'll see in the next plate...), the substrate can be (lightly) scrubbed off using a swab soaked in ethanol, leaving damn near factory perfect letters behind.


So about that cool part. I placed the bezel on a vent to dry after placing the logotype decal, but didn't wait long enough for it to cool down (it was only 10 degrees above ambient or so) before swabbing off the substrate, and lost a few letters. Back to Radio Daze for another sheet, as this was the second attempt to get it right. The waiting is the hardest part.

Either way, it's almost done and this is the "money shot" for now "llic a ers co." branding and all:


Anyway, hope someone enjoys this. I wanted a sharp looking and fun vintage shortwave radio for the living room table, and this little box fits the bill quite well.
All I really have left to do is get a new outer dial glass, add warm white LED dial lights, fix the decal issue and put on another couple coats of clear urethane, if there's any interest I'll post the final.

Well, that and aligning it...but it's at least usable as-is, and works quite well!

[All work was done with appropriate safety precautions and isolation, don't attempt similar if you're not comfortable working with mains voltage and aware of subtle risks, particularly if probing with a scope.]
« Last Edit: May 02, 2016, 04:37:08 am by kmm »
 

Offline AF6LJ

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Re: Repro glass dial scale for a Hallicrafters S-38D?
« Reply #5 on: May 02, 2016, 02:22:40 pm »
I have a term I use to describe what you did, I call it Rehabilitation; after all it is not restoration. That was a well executed rehab....

Sue AF6LJ
Test Equipment Addict, And Proud Of It.
 

Offline Cubdriver

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Re: Repro glass dial scale for a Hallicrafters S-38D?
« Reply #6 on: May 03, 2016, 03:13:42 am »
Very nicely done!   :-+

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 

Offline VK5RC

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Re: Repro glass dial scale for a Hallicrafters S-38D?
« Reply #7 on: May 05, 2016, 10:22:05 am »
A lovely job,  something to be really proud of!
Whoah! Watch where that landed we might need it later.
 


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