First off,I have done quite a bit of K&T re-work for my young age of 35... And a bit of lab work on the electronics soldering side.

However, the lost art of K&T splicing and soldering is a dying art IMO. And recent newbies have no clue to the stuff.... I used to work with some old salts who are now retired, and learned what limited stuff I know from them, and as all the old guys disappear, I find I have now explain K&T often. - So, I'm thinking of writing a little lesson on it. (Well not so little, its 12 pages now, but has some poor illistrations.)

Anyway, I have some questions to clarify about the use of solder pots, and open flame heated irons? (Something I was never around for.)

• Did you guys really recycle solder splashes off the floor for re-use, and was this practice frowned apon?
• What was the preffered method for tap splices in framing, iron and stick solder, or iron to heat, and poured?
• Were poured joints fluxed?
• At some point joints were required to be in boxes, and it seems soldering was still in vogue, how were these joints done?

Any other information is also heplfull....

Mark,
When I started my time as an Apprentice Line-Mechanic all of our underground joints were Solder type.
You had a Solder pot in the trench.
Live or not, that was how cables were jointed.
This was before we had any crimp connectors.
You tinned the conductors (both copper) in the pot and then put a sleeve over the top of the two cables, heated it with a blow-torch and then filled both ends with solder dipped in killed spirits (Muratic Acid I think it was called), that was your flux.
If you were lucky, you'd get out of the trench without your Goloshes catching fire.
And am I alone in the people that used to work under a PoCo(Or Telco) tent and have some school-kid come and open the flap, just when you are trying to make a joint and let the wind in and say "Ahh Just Smoko time is it?".
Soldering is a skill they should be teaching all new people to our trade.

Mark,
What is a poured joint?
Don

My grandfather was an old time electrician and he talked about the old timey stuff but by the 50s he had a big electric iron he used and taught me to use. This was probably about 200w and it soldered #12 like you would do hook up wire. He used roll solder once it was available

Mark,
What is a "K&T"? Is this a slang term or regional name?

I've been in the trade since 1973 and this is the first I've heard of it.

Don,
A poured joint was when you wrapped your wires and then set a casing around it and then filled it with solder.
They used that over here until the 1940's.
Bill,
K&T is Knob and Tube.

Back around 1962 I was in 2nd grade, and the local phone company used solder to seal up junction box like cylindars on their heavy phone trunk cables that were strung pole to pole along the street. Seems that they spilled molten solder on the ground next to our school playground (luckily no kids were out there when it happened). But later, after the spilled solder globs had cooled, it was recess time and all us kids were fascinated by the pretty little spoon shaped globs all over the ground. Brought some of it home to play with some more. My father recognized it for what it was, and told me not to eat it, and wash my hands after handling it.

Today the area wlod have been declared a Superfund toxic spill site... Along with that classroom where some kid brought in some mercury to play with and the teacher got mad and slapped the kid around, and the mercury spilled throughtout the classroom.

First off, Trump, thanks for the info, and yes I totally agree "Soldering is a skill they should be teaching all new people to our trade." Which is why I'm on this little mission. I keep getting these "Rope-A-Dopes" that slither out of the spec'ulative housing out in the burbs who have no clue on remodels as help these days. I only say that because IMO to be a "true" journey' should have a full if not semi-round of experiance. Show them anything other than romex, and they get wide-eyed. The thing is that most of the housing and commercial stock in the city and area we work in pre-dates from 1890 - 1970+. There is very little in way of new construction here... That said, I get to demo a lot of very old work, and often intregrate it into the new. And, seeing that it seems I am the only guy in the company that knows what to do with it, I have go do it... Every one has an employee handbook, and if I write something that explains the 'hows' of it to add the handbook, then I don't have run around to every job to tie in the old stuff. I figure it doesn't have to be scientific or too historical. But I dont want to mis-represent the past I wasn't around for either. I only know what I have been told, and some of it confuses me too.

Anyway, I'm popping this up on one of my sites, feel free to take a look, and critique if you like. Bear in mind it is still in edit stage, and needs a little more work.

[URL=http://www.markhellerelectric.com/wusplice.pdf]K&T splicing[URL]

[This message has been edited by e57 (edited 06-04-2006).]

My Father did a little K&T New work, back when He first got into Electrical Contracting + He saw some of the "Old Timers" doing K&T work when He was still working as a Residential Framer / Carpenter.

He mentioned the "Dip Pots", which were used to tin the stripped Conductors. They were dipped into a Solder/Flux mixture (similar to Rosin or Acid Core Solders, I guess???...). This was heated by something similar to a "Pocket heater" which uses Napthalene as fuel, and has a "Contained" flame (like a large Zippo Lighter which keeps the flame lit when the top cover is closed).

After tinning, the Conductors were "Tied" into a "Joint" - typically a "Western Union" type of joint was used.

With the joint made, heat was applied to the central point of the joint, using either an Electric Iron, or a torch.
Rolled Solder was applied to the joint, which I would imagine had some type of Flux (either inert or paste applied with a brush).

After the joint cooled, tape was applied. The type of tape used is like a Cambric type of Friction Tape.

Some would reuse the dripped off Solder (dropping it into the tinning pot), others just left it for _Someone Else_ to deal with (i.e., Mr. Broom Pusher).

When I do any K&T work, I use Rosin Core Solder for tinning and finished joint. I use a 200 Watt Soldering Gun for the heat source (Induction type - like a small hand held Arc Welder, with a heating lead instead of an output arc - the typical Soldering Gun!).

To insulate and seal the joint, I use Heat Shrink tube and a few layers of "Good" Black Electrical Tape.

Wish I had more to contribute.

Scott35

Mark,

I just checked out your Word Document regarding K&T.

Good Job!!!

May I use it to assist with training, for similar inexperienced personnel?

Scott35

edited for spelling blunders!

[This message has been edited by Scott35 (edited 05-19-2006).]

I made up some western union splices for a BB, either here or the home inspectors, and I just used my trusty old Weller 200w gun. It worked great on #12

Scott of course you can use it... I'm not quite done yet though, I still have to do some work on that document.

AND, I was just sent me some FANTASTIC scans of an old lesson on the matter from 1926, there is some worry about copywrites so not sure about the posting of them. So there may be some more to absorb, decipher into modern language and add later.

Anyway, I have not read the whole thing yet, but in it I found this gem.
They to this day pipe eveything, with limited use of flex...

Mark, with 394.17, if the 3" wire protection above a horizontal framing member is to keep plaster from accumulating around the wire, would there need to be protection above the top plate? There shouldn't be any plaster above the plate and I can't remember ever seeing a tube stacked over the one running through the top plate(s).
The code statement "Where passing through wood cross members in plastered partitions" sounds like fireblocking or diagonal blocking inside the wall stud bay.

394.30, "every 4 ½’ and at 6” minimum on each conductor coming to a tap, or splice." Shouldn't that be no more than 6" from the splice?
Within 150 mm (6 in.) of each side of each tap or splice

When I think of "acid" flux or acid core, I think of flux used for soldering sheet metal and those containers state not for soldering electrical connections. Should the wording be "rosin flux"?

steve

K&T wiring worked very well since the K, - i.e. Knobs, and - T, i.e Tubes, were usually made of porcelain, a very good insulator, as you probably know.

Joints are another story.

Proper solder techniques were the artform in K&T wiring.

The only real secret to doing the soldering was to use rosin fluxcore solder and not acid core stuff. Insulation of conductors was exceedingly crucial and most intsallation of K&T survives to today and has not caused a problem around my part of the world.

The only issue I've run into is the HO that wants to upgrade a now really older home to modern standards like new ranges, A/C and electric clothes dryers (although in Alberta I can't for the life of me figure out why gas wouldn't be the fuel of choice). It has always become a TOTAL rewire, with no other options available including every home run in the house.

The other folks that are just buying these homes usually can't afford that, so I am still adept and able to deal with a repair (although infrequent) to K&T stuff.

Upgrades and soldering in J boxes is a skill not learned or taught in schools much any more but only by seeing what us old farts do when going at K&T in a house built in 1925.

Hope that helps.

Steve, I have on occassion seen tubes above the top plate, but agree that in most cases not nessesary. And thank you for catching that wording use of "Minimum" v. "no more than". The early versions of flux were muratic acid and other chemicals. In the 1926 lesson Alan Nadon graciously sent me, had instructions on how to make your own, out of muratic acid, and zink from a "used dry cell". It too also suggested not to use on electrical connections. What I haven't gotten to yet, is that all joints need to be cleaned well afterwards, be it acid or rosin. Both will contain any oxides that came off the wire in the process. Rosin contains some very long named clorides that rot joints pretty good over time. And most rosin fluxes intended for electrical use also contain active acids of some type or another to react with the resins. (I learned this too long ago, but found a great explaination of it here. )And non-rosin type fluxes intented for electracal use which are acid based in various ways. Which is what I intended by the use of "Acid" in the document. (I find these type of fluxes easier to use and clean afterwards.)

Like these: http://www.solders.com/395_alcohol_based_flux.htm http://www.solders.com/802_resin_free_flux.htm
http://www.solders.com/109_water_soluble_flux.htm

Either way, suggestion taken, and I just may well take "acid" out of the final document to illiminate confussion. As there are certain types of fluxes not intended for electrical use. That is why I posted it for the valued critique. Or take a long deep dive into the chemical properties of flux... Which I just might do. It is a work in progress...

My personal prefference is to stay away from cored solder all together, they are great for electronics work, but on larger conductors just dont work very well.

Edit to add link about the acid reaction in rosin solders.

[This message has been edited by e57 (edited 05-20-2006).]

Here's some info I found. (Of course I am still a very young man) in an old American Electrician's Handbook.

Re: Flux



Re: Poured Joints



I started a thread in The Nostalgia Area, and posted the full text, which shows different ways of wire preparation, etc. and has pictures of various k&t parts.
That way I won't hog up a bunch of space in this thread, and make it slow to load for those that aren't that interested in it.

The thread in Nostalgia is Here



[This message has been edited by electure (edited 05-21-2006).]

Gent's I think I have finished my diatribe on the subject....
http://www.markhellerelectric.com/wusplice.pdf

The last K&T I encountered was in Hawaii: bare copper running within 9" overhead of anyone using a shower installed by the homeowner on Ahinahina street.

As for solder... forget it. I'd always go with compression connectors and a transition to Romex.

Greenlee Gator ECCX to the rescue.

They make a die for #14 - #12????