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Author Topic: Wax For Sealing Oscillator Coils and Electrical Windings Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 09-01-2006 09:46 PM                  Actually "dog bone" (radial lead) resistors as used in the old electronic equipment from the 30's-60's (and before/beyond) are carbon composition and not WW. They are usually coated with ceramic, epoxy, or just a painted carbon core. More recent ones are carbon film with spiral grooves laser-cut into them to determine their final resistance and considered "precision". Forgot who said it, but it's true the "dog bone" caps (condensers) were used for temp compensation in critical circuits and had a negative temp coefficient to offset the positive temp coefficient of resistors and inductors. The net result was (almost) a stable circuit that held it's freq and other characteristics. In the more expensive and more critical applications, all the freq determining components (including in most cases the vacuum tube or transistor osc) were enclosed in a temp controlled compartment known as an "oven". As far as the beeswax... I'd look for a better modern replacement... BTW: Speaking of dog-bone resistors and "condensers", many anal-retentive restorers will go so far as to make their own dog bone, (radial lead) components. They (epoxy?) mold new axial-lead resistors or caps into a "dog-bone" form and paint them to look like an original. I ***cannot*** buy into to those anal-retentive guys that HAVE to have it and MAKE IT LOOK "original"! I mean WTF **REALLY** cares??? Not ME! Fer sure!  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 09-01-2006 10:11 PM                     quote: Phil Hill Actually "dog bone" (radial lead) resistors as used in the old electronic equipment from the 30's-60's (and before/beyond) are carbon composition and not WW. I do have a piece of H-P test equipment that uses dog bone resistors that are wire wound. You can see the turns through the enamel coating. Will try to look for them and post a photo. Tektronix also used tons of dog bone resistors and caps up through the mid 70's. Mark  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 09-01-2006 10:17 PM                     quote: I ***cannot*** buy into to those anal-retentive guys that HAVE to have it and MAKE IT LOOK "original"! If the original designers had some of the modern materials, back then, that we have today, they would have used them. (The use of vacuum tubes not withstanding.) If an old radio is worth keeping it's worth fixing up according to modern standards. The only exception being rare and expensive models. But, those belong in museums in the first place.  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 09-02-2006 01:14 AM                     With my radio I want to be able to safely and reliably use and enjoy it on a daily basis. So, I am restoring with modern components of the correct values per schematic. Another reason for the modern components is that reliable origonals are no longer available. Among my modern components are the wire, resistors and caps. Using modern UL1015 18AWG throughout. Some of the antique radio supply outfits have colth coverd (UL1015) wire, but they do not have all the color codes I require. All my resistors are NTE 2% Flameproof...what the store had on the shelf. Yes, there are those restorers anal about keeping a 100% original radio...even if it is not working. There is one outfit reproducing wax/paper caps. And yet there are those restorers that will gut those origonal caps and stuff new ones inside to retain original appearance. There are also methods of opening up micas and restuffing them. Ditto with chassis mounted E-cap cans. From what I gather the antique radio hobby is very finiky! Radios with roughly 15 tubes or more are the high dollar items. I did ask about donating my 816K to a musuem after I am no longer here...for safe keeping. The consensus response has been "good luck!" What is really disgusting is seeing people who by upold radios for their cabinets...throwing away original chassis and instaqlling modern low-end audio crap! I actually had one individual say to me the other day "Why bother restoring an old tube radio...they never held their tuning". So, I asked the person to explain himself which he of course could not do. Cheers Kutler  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 09-02-2006 07:36 AM                     How a restoration is done is all up to the individual and how much he/she is into it. I also prefer the reliability aspect of making something old working again. Burning one's house down for the sake of making a capacitor or resistor look old is really stupid. Mark  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 09-02-2006 03:26 PM                  I basically agree Mark & Will. For me, as I said, I want it to be safe as well as perform and look close to the original as "reasonable." I guess other than replacing worn playfields with NOS playfields in electro-mechanical and early mircoprocessor pinballs, or re-chroming pitted jukebox trim, the most sinful restoring thing I've done is replace burnt video game CRT monitors with modern flat-screen monitors.  |  IP: Logged Charles Greenlee Jedi Master Film Handler Posts: 801 From: Savannah, Ga, U.S. Registered: Jun 2006 posted 09-06-2006 02:01 AM                        I preferr honoring the original design as best I can. I'd check everything I could to make sure it was in working order. If there is something I have to replace, I will replace it with the best equivalent. I.e., If I replace a red wire that is worn to the metal, I will replace it with a new, modern, poly coated red wire. It still follows the color scheme and performs the same function, AND adds better safety and performance. External components on things such as an old console radio, I'd try to keep original for cosmetic purposes, but internal, I won't shy away from replaceing an old wax sealed cap with it's updated modern equivalent, if the old one needs it. As long as the schematic is the same. If its a tube, I may try to find it in an exact NOS, but probably I'd be forced to see if there is a modern interchangeable tube still in production, which I would hope would be superior.  |  IP: Logged Josh Jones Redhat Posts: 1207 From: Plano, TX Registered: Apr 2000 posted 09-07-2006 11:13 PM                        I have used hot glue on RF coils in the past with no ill effects. Haults microphonic action as well. JJ  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 09-08-2006 11:42 PM                     I am going to attempt contact with the Materials Engineering dept at ASU Tempe. Maybe they will be able to analyze some original wax for me to see if it is parafin or beeswax...as well as any other noted additives? Cheers Kutler  |  IP: Logged Jeff Stricker Master Film Handler Posts: 481 From: Calumet, Mi USA Registered: Nov 1999 posted 09-09-2006 05:47 AM                     Will, try these guys. What a collection of finely restored radios at their museum. Indiana Historical Radio Society  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 09-09-2006 12:46 PM                     Josh, You can't peel off hot glye on a coil wound from #48 enameled wire! Its fine for the plumbing that you work on though. Mark  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 09-10-2006 06:57 PM                     Hi Mark Ditto on what you just said! What Josh said is a sure fire way to really screw-up coils wound out of Litz Wire! My problem was that it looked like the wire on my oscillator coils were all solid strand red-enameled. This belief held true because after melting off the original wax, I lightly cleaned the coils with Q-Tips dipped in MEK (MEK being the carrier agent in Q-Dope). No harm came to the coils with this light cleaning, hence I thought that my enameled wire analysis was correct. Was I wrong! Two of the critical coils were Litz wire. Three or four strands only visible under magnification covered in cotton and then red lacquered?? over. And the physicall appearance of that red coating also looked as though the wire was single-solid strand!! While I did not break any wire, the Q-Dope did a great job of dissolving the red coating and damaging the underlying cotton insulation! So, I do not know if these coils are now junk? But I am lucky! I located a parts chassis which is now on the way! But I will redip my original coils in wax and test them...keeping all body parts crossed in hopes that the coils are still good! Unfortunately I do not think that I can rewind these coils, as they were originally machine wound with obvious special patterns. Boy am I glad that I did not tackle my IF transformers with Q-Dope...then I would really have been up CREEK!  |  IP: Logged

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