I'm working on a peculiar Atwater Kent Radiodyne breadboard needing some lengths of "varnished cambric sleeving". This insulation is made to cover 18 gauge solid buss wire and has a dark brown, glossy covering. I've been around a long time and have never seen a modern equivalent to this sleeving with the exact same appearance. I have come up with a replication method in my home shop that matches very closely to the original. It really takes little labor but there are at least three overnight drying periods required.

It has solved my current restoration challenge.... Here is the text and photo of my article completed today... This post may remain on ARF forever.

Making Atwater Kent Breadboard Buss Sleeving
By Robert Lozier – KD4HSH
kd4hsh@carolina.rr.com
Many of us interested in the first generation of broadcast receivers made in the early 1920s are fascinated by the Atwater Kent “open sets�. The company had entered the radio manufacturing market by making individual components designed to be mounted onto, usually wood, panels. They were absolute masters in turning-out the highest quality Bakelite moldings to house or support their electrical parts. They expanded their product line and eventually offered fully assembled radios. The components were interconnected using single strand copper buss wire. (18 AWG) All the top side wires were covered by lengths of sleeving generically called “varnished cambric tubing�. This tubing is tightly braided linen thread coated with multiple coats of translucent dark amber varnish. Over time it becomes a dark, glossy brown and most becomes brittle. Lengths of the same tubing are also used on the underside of the baseboard.

The unhappy truth is that some of this sleeving breaks off or is gnawed-off by insects or mice and replacements must be found, however I have not been successful in finding any modern equivalents that come anywhere close to appearing true to the original.
It is very difficult to photograph this tubing but maybe this shot will give you some idea of what is possible.
That sent me off on a quest to find a way to make convincing replica sleeving in my home shop.

Hobby shops have lengths of “music wire� used in model aircraft building. Buy a length of 0.047� to 0.055� diameter. (A popular brand is K & S Engineering part number 502 or 503) Cut the wire to about 20�. Slip a length of 3/32� 2:1 thin wall polyolefin shrink tubing over the music wire and use a temperature regulated heat gun to carefully shrink the tubing completely. Be sure to allow air to escape completely, you cannot tolerate any trapped air bumps in the finished diameter.
There is a brand of 3mm dia. waxed cotton beading cord available from this link: https://www.firemountaingems.com/itemdetails/h201349bs. Similar “3mm Waxed Cotton� cord is available in some craft stores in seven-yard lengths.…. Do not use 3mm Cotton Macramé cord because the braiding threads are much too coarse.
This waxed cotton bead cord consists of a tightly braided tube over parallel strands of filler cord. Use tweezers to pull out the filler strands on a length of cord that is about 1 ½ times longer than your length of music wire. Your hollow braided cotton tube can now be slipped over the shrink tubing. Pushing this braid over the shrink tubing is not a fun task, but I can do it in about 12 to 15 minutes. It is an easier task if you use the 0.047 diameter music wire. Take time to stretch the braid evenly along your core of heat shrink and music wire.
Now you are ready to coat your sleeving with alcohol base “medium walnut� wood dye. I use Mohawk “Ultra� Penetrating Stain. For drying, support your length of sleeving by clamping the wire on one end so it does not have to lay across its length.
After drying, coat the sleeving with a mixture of “Titebond Veneer Glue� and the same wood dye mixed to the color of milk chocolate. Brush vigorously into the sleeving but finish by removing any excess from the surface. As the glue becomes almost dry, transfer it to a plate of glass or Plexiglass. Use a card size plate of steel or plastic to roll the length back and forth to compress the cotton fibers. You may need to repeat this a few times to get the best effect. This fills the pores of the braiding and imparts the dark brown and glossy color to the finished sleeving. I use a cabinetmaker’s “cabinet scrape� to roll the tubing. When you roll the tubing, some of the glue will stick to the glass, the scraper makes it easy to scrape this residue off the glass.
Allow the wood glue to cure overnight. Use 220 sandpaper to lightly sand away any fuzz and wipe clean very lightly with a tack rag. Put on new rubber gloves and clamp only the music wire end into a bench vise and carefully pull the tubing off the wire. In other words, the shrink fit tubing remains the inside wall of your finished product and the gloves prevent skin oils from contaminating your tubing.
The sleeving is finished by brushing with marine spar varnish. This varnish has a heavy body and a transparent amber hue. Indoor spar varnish is much thinner and therefore you will have to apply more coats to achieve a smooth finish.
The finished product is very, very close to the look and function of the original varnished cambric tubing. So close as to be intermixed with the vintage sleeving without attracting attention to how clever you might have been in your restoration activities.

Robert

That looks like the real-deal, Robert. Nice work.
Its a shame that there isn't a ready to use replacement out there. I can't imagine that it would be terribly difficult to manufacture such a product commercially.

Good work Robert, let me know when your going to sell some, I'll be your first customer.

Brilliant. Worth doing for those special radios.

Gary

can you use the brown cord? https://www.firemountaingems.com/itemdetails/h201353bs , and forgo the dying step?

Humm.... Did not see that...

In this case I don't think I would be stocking the brown because I use the white cord when I want to make a length of fabric covered wire of other colors... The white cotton can be dyed after you wash-out the wax.

I already have the Mohawk Ultra Medium Walnut stain that I use to color the Titebond Veneer Glue for application on this replica sleeving...

So in general, I'm thinking the white is more versatile for my shop work.

All the best,
Robert

Fantastic!

If you wish to try making your own and wish to order supplies, I encountered what I think is bizarre.... I decided to go to Amazon to see if there were alternative sources for the 3mm cord referenced above. (Which is indeed satisfactory for this project.). I found a 3mm waxed beading cord that in bold type at the top of the page proclaims that it is "cotton"... has the words "Korea" and "Ivory" color also in bold type. So I ordered it. What came in the mail was a spool of brilliant white, 100% polyester cord with no indication that it was Korean. (A material that I cannot dye.) The vendor would not allow me to return the product or issue a refund. The vendor stated that the bold type heading was just a 'name' for their product and that it does not relate to what it actually is... They pointed out that in small print farther down in the page, the words "Material: Polyester" correctly describes the product that they shipped to me. They made no mention of the color shipped or country of origin.... So a word to the wise I guess is, read all the small print text.

Yep, got stuck in a similar trap this year.

Hello Robert,
nice job it looks fantastic.

Over here in the UK, cloth covered wire is very difficult to get, I use this stuff, sorry it's ebay uk

https://www.ebay.co.uk/itm/EVERLASTO-NA ... 2749.l2649

Made from cotton, it does have inner strands, these are easily removed, it dye's really well.
To stop any fraying I use a dip coat of blonde shellac, clear laquer could be used, both need to be thin, my shellac is sanding sealer viscosity.
A big plus is the cord is not waxed, but I do recommend washing before putting in the dye.

Those colors look great! I'm guessing if I could get 4mm cord, it would permit making an insulation sleeving for 12 gauge buss wire seen in many US radios of the day. BTW - I've discovered that you can now buy small assortments of high flexibility silicone rubber insulated wiring in 300 and 600 volt ratings similar to Type UL3132
https://www.amazon.com/Stranded-Nano-Fl ... B07JB5G82W It conforms much better than PVC insulated wire... I used it here in connecting these AK transformers.... The original wire is rubber covered and completely disintegrated. These new silicone wires simply look too new, so I hid them inside the cotton sleeves... Not absolutely authentic but appears much more harmonious than plastic insulation. Eh?

Robert

You may find that the silicone is a little difficult to put inside the fabric sleeve due to the silicone not being as slippery,
I use 18gauge tinned copper wire for under chassis work, when wrapped in the cotton cover it's good for 600v or so,
If you are worried about high voltage use enamelled wire modern stuff is good for several kv.
Using silicone rubber does make the wire look original as it is very close in appearance to the old type

Robert, did you see this item, https://www.sunenterprises.eu/en/round- ... 14594.html

This is advertised as waxed cotton, round 4mm.

Can the flat bead be used? I am looking for something to insulate square buss bar that looks period.

Hope all is well,

David W.

David,
I don't know how the flat version of this cord is constructed.... You may have noticed that some flat shoe laces are cylindrical while others are braided to be a flat ribbon. It is interesting how critical the eye can be.... I have a Cutting & Washington 11A with 12 gauge square buss wire and a few bits of sleeving here and there. While my 3mm replica sleeving like made for the AK breadboard sets looks pretty good in hand; when placed next to the 4mm sleeving the difference in size jumps out at me.

When I purchased my cord from https://www.firemountaingems.com/ I sent a query first and they confirmed the construction of the 3mm cord I ordered. maybe an email will get a response on the 4mm construction. It kind-of looks on their product picture that is is indeed a flat tape.... Not hollow...

Robert

Robert, Thank you for the words of wisdom.

R,

David

Round hollow braid is made on braiding with a small mandrel to form the braid. To create a flat but hollow braid, draw the materiel over a heated roller to take "set". A flat , "tape" braid is also made on the same machine with a change in the braid table using end quoits and braid end forming "picks". It is fascinating to see a flat braid machine in operation, it looks like it is about to tangle itself up at any moment. I had the pleasure of touring a local braiding factory this past January.

Kudos Robert, making the impossible.

I looked through the RI wire website, mention was made of a lacquer tower... Since they over-braid their wires, certainly could explore commercial manufacture of varnished cambric.

Chas

FYI, I have refined my method to make replica tubing.... I have encountered two rare radios from the early 1920s that require 12 to 14 FEET! of tubing per radio. My original process presented problems of being able to actually extract the music wire mandrel. The new process completely eliminates that problem. A simple fixture allows me to process four lengths at a time. Also I had originally used Mohawk aniline wood dye to color the white cotton braid and also color the glue. I found it much better to dye the braid with common RIT fabric dye and to color the glue with TransTint liquid dye: https://www.woodcraft.com/products/tran ... oney-amber expensive, but a 2 oz. bottle is a lifetime supply for what I do. You would use the medium brown (I think) for the AK replica tubing. The high alcohol content of the Mohawk stain tends to curdle the glue. I don't see that with the TransTint liquid.
Don't know when I'll get around to posting on my website...
Robert

Hummm..... These images are not high enough resolution.... If you want a .pdf in high rez. just PM me....
Robert

This is a very interesting & helpful thread. I'm restoring an AK 12 (4910) breadboard, and the cambric on this is disintegrating. So when i first read Mr. Lozier's procedure i thought, "This is crazy, nobody has time for all this." But i re-read it and realized i already had everything in my shop that was needed except for the cotton cord. That was easy to find online. And it turns out the process is not difficult to do in practice. It only took me about 30 min of actual labor (i.e. not counting drying times) to produce about 10 linear feet of genuine fake 1920's cambric! Cool! It's so closely matched in color and texture that the only give-away is that it's in perfect condition.

For the stain, i used General Finishes water-based dye stain, Medium Brown because i already use this stuff in my woodworking, and the color very closely matches the original cambric. The can says water-based, which means it contains ethanol. The point of using this stain is that it's thin and soaks into the cotton very nicely and evaporates fast. G.F. also has Light Brown if it needs to be less dark in color. For the varnish i decided to try a tiny little 8 oz. can of Ace Hardware solvent-based "Spar Varnish" (#273B110 Clear) from our local store. 10 bucks and it's enough for a lifetime for cambric projects. I can't vouch that it's any good for sailboats, but it turned out that one coat of this was plenty thick enough for my cambric, though it took about 2 days to fully dry. It might have helped that i used an inexpensive foam brush. I use these all the time on wood so i just used what i already had.

I am very pleased with the results of this (see photographs). My thanks to Mr. Lozier for figuring this out and posting it. My advice to others is don't be afraid to try it.