Prewar Wiring Terminal Insulation

[ryan95]

I am thinking ahead about how I will do the wiring for the 23 Moon, and am trying to figure out what to do about insulating the terminals. I plan on using cloth covered wire and open barrel crimp terminals like the original wiring was. Looking at how others have done the terminals for restorations, I notice most have been done with heat shrink tubing on the terminals. What was the original way to do it for prewar cars with cloth wiring? Heat shrink tubing is wonderful stuff and looks very clean, but I really doubt it was around 100 years ago. Either there was no insulation or another method was used. I'll attach a picture for reference.

 

[Bloo]

Rhode Island Wire has black tubing, essentially rubber hose, but made for this purpose and in the right dimensions. You push/stretch it over the connection after soldering. It may be the original method, but it is also possible the original rubber may have been vulcanized in place. After all they thought nothing of vulcanizing a tire patch in place in those days. Either way, it hits the original look closer than heatshrink does.

[ryan95]

Bloo, the product from RI Wire, are you referring to the asphalt covered cloth wire loom? I haven't used the stuff before, but that was one of my ideas. I figured it was too rigid, but maybe with some heat it becomes malleable.

[Bloo]

No  it is literally like hose. You use some that is a little tight and force it on there after the fact. Here's an example, sorry for the awful pics. the pictures are years old, taken to show something else, and turned out blurry.

 

On the RI Wire site, go to "Metal and Non-Metal Conduit Tubes" and then scroll down to "Neoprene Tube" for a table of sizes. I don't see any way to link it directly.
 

Original from the period:

 

 

Rhode Island Wire stuff:

 

 

 

Edited February 13, 2022 by Bloo (see edit history)

[ryan95]

Thanks for the idea. That looks reasonably accurate since vulcanizing would be difficult I imagine. Does anyone have more to say on the original process or processes of the time? Any other solutions?

[TerryB]

I was in the electronics world working for RCA and I can tell you heat shrink tubing is a lot more recent discovery than the timeframe you are dealing with.

 

Edit- Just found that it was invented in 1962 so given it would take a few years to develop a market for it would put it into the late 1960s.  I first saw it used in the early 1970s.

Edited February 13, 2022 by TerryB (see edit history)

[1930 Kram66]

I didn't want to use heat shrink to insulate my terminations either. I used self amalgamating tape.

It's likely not correct either, but to my eye it has an old style look . 

 

 

[ryan95]

That's another interesting option. I'm going to take another look at the original wiring tomorrow and see if I can find any traces of vulcanized rubber. If that is what was used, I would like to try and find what looks closest to original.

[ArticiferTom]

Rubber covering used as archery bow string to site aligner . Also used on eye glasses lanyard attaching ends . very soft and stretchable . 

[Bloo]

There is also a period method that involves wrapping with string and maybe beeswax(?). I don't know exactly how it was done. A period repair probably would have been friction tape. Let us know what you come up with.

 

Edited February 14, 2022 by Bloo (see edit history)

[ryan95]

I'd like to see if I can dig up some period pictures or a description of what it actually was. I also have  heard of the linen wrapped terminals, but have yet to see an example. I'll give updates as I make progress.

[Bloo]

My guess is the string used in that method was probably the same type of waxed linen thread used for tying harnesses in the electronics and telephone industries.

[hook]

Here is how The Franklin automobile company did it. It is also the same wire end tubing pieces you can get from Rhode Island wire.

Notice on the first drawing the wire boot is called out with drawing #27424. Drawing #27424 covers all Franklins from 1921 to 1934. Also on the first drawing is the instructions for all wiring connections, splices, and harness covering.

Hope this helps

[hook]

Here's a photo of the Rhode Island Wire harness of the same, using their rubber tubes.

[ryan95]

Hook, that looks like it's probably going to be the best option unless I hear of something better. I cannot find it on their website, but I'll call when I'm about to order supplies. They have plenty of other things I'm looking for. Here are two styles that I found on the original wiring so far. The first is from the ignition switch. It looks textured. The second is the distributor wire. The insulation on it looks like a smooth blob. The next time I go to the other garage where the rest of the parts are I will see if there are any other clues. Most of the terminals have no insulation, so those ones were either bare originally or the insulation decayed and fell off.

[hook]

18 minutes ago, ryan95 said:

Hook, that looks like it's probably going to be the best option unless I hear of something better. I cannot find it on their website, but I'll call when I'm about to order supplies. They have plenty of other things I'm looking for. Here are two styles that I found on the original wiring so far. The first is from the ignition switch. It looks textured. The second is the distributor wire. The insulation on it looks like a smooth blob. The next time I go to the other garage where the rest of the parts are I will see if there are any other clues. Most of the terminals have no insulation, so those ones were either bare originally or the insulation decayed and fell off.

Look in Rhode Island Wire under "metal and Non-metal conduit" and you'll find Neoprene tubing that can be used as the original set-up used in the 20's. You just have to decide what ID size to use. 

[Str8-8-Dave]

My Harnesses Unlimited harness connectors are all done like the picture of the Rhode Island terminal insulation and a length of the rubber tube was included with the harness kit for addition of non-stock accessories like heaters and Trippe light or turn signal adds. 

[hook]

2 hours ago, ryan95 said:

Hook, that looks like it's probably going to be the best option unless I hear of something better. I cannot find it on their website, but I'll call when I'm about to order supplies. They have plenty of other things I'm looking for. Here are two styles that I found on the original wiring so far. The first is from the ignition switch. It looks textured. The second is the distributor wire. The insulation on it looks like a smooth blob. The next time I go to the other garage where the rest of the parts are I will see if there are any other clues. Most of the terminals have no insulation, so those ones were either bare originally or the insulation decayed and fell off.

After looking at your connectors, I seriously doubt that the top one (the one you call textured) is original. Back then most all connections were soldered. They clamped on also, but they were soldered. Unlike today that's just slam bam thankyou mam.

[TerryB]

Crimping wires has been found to be better at preventing vibration related stress and breakage than soldered connections.  In the early days of automobiles this information was not as well documented as it is today. Heating the copper wires creates brittleness that can lead to intermittent connections or outright failure of the joint.  In applications where wire motion and vibration are not common solder is fine.

[Bloo]

@TerryB As someone who spent a lot of my career repairing screwed up engine control systems, I think we may have to agree to disagree on this one. You are correct that crimping, properly done, is more resistant to outright breakage from vibration. Crimping is terrible, on the other hand, for keeping stray resistance under control. It doesn't age well at all.

 

 

 

[TerryB]

I observed in my early days, the Japanese on their motorcycles were very good at going to extra effort to shield their connections from the elements using clear plastic hoods to keep connections clean and dry. When dollars are involved I’m sure that level of effort was not done on domestic automotive applications.  In the TV business the changeover to crimp joints was very common as TVs did not get subjected to the elements and vibration like automobiles.  Still, we always examined crimping joints closely for defects however the biggest recalls for us were solder related joints that failed under heating and cooling stress.

 

Your real world experiences in the repair field are always good to know.  Just think, if the connections were perfect, you would have no work!

[37_Roadmaster_C]

@Bloo and I argue almost weekly about soldered VS. crimped connections and I am sure both of us are correct at times  .  One thing that is absolutely beyond argument is that for a crimped connection to be acceptable is to use the correct tool to make the correct crimp. If you google crimp tools you will find hundreds priced from $5.00 to $1000.00 or more. Most are a type of universal tool and are simply crap tools. If you are going to crimp automotive wiring with standard ring, fork, spade and the like connectors, spend the money on a GOOD crimp tool.  Thomas and Betts, Paladin, Molex and others make them. I prefer the type that have interchangeable dies for different connectors. The cheap crimpers you get in the connector sets are the worse of the worst. They do not crimp with proper pressure, they cut insulation and after a few crimps they tend to start distorting and the jaws slip out of alignment as you crimp, often cutting both the insulation and the inner sleeve.  If you are going to crimp pony up the $100+ for a proper tool.  Remember, proper tools for a proper job..............

Edited February 14, 2022 by 37_Roadmaster_C (see edit history)

[TerryB]

At work we were mostly Molex pins and plastic plug bodies with an occasional AMP connector.  Molex held up extremely well.  

[ryan95]

I agree on good crimps being necessary and having the correct tool for the style terminal being used. Wiring became so much easier when I learned how to do it right. When I see some of my early crimps I cringe.

[Frank DuVal]

8 hours ago, Bloo said:

Crimping is terrible, on the other hand, for keeping stray resistance under control. It doesn't age well at all.

Ever fly in an airplane? See the manufacture date as you step into them (data plate is near the "front" door), all crimp connections. Solder adds too much weight also for things that fly. But, the tooling used costs a lot more than that set of pliers you use for crimping your projects!😁

 

NASA also has no use for soldered connections.

[Frank DuVal]

5 hours ago, ryan95 said:

When I see some of my early crimps I cringe.

Ha! Like when I was young and broke I pried open many a Packard 56 style crimp connector and reused them!😲

[37_Roadmaster_C]

Yep, When we were young we .....  Nope, not here or anywhere...

[Bloo]

Airplanes have frequent government mandated inspections and maintenance to take care of any looming problems before they crop up in the air. I have a box of wire here that is identical to wire that is commonly used in space, and I can assure you it in no way resembles anything you will find in a car. For one thing, the strands are well plated with something that never seems to oxidize. For another, the quality is extremely high.

 

I can only really comment on what you will find in a car, as that is my area. You will typically find wire made of bare copper strands. When you crimp a terminal to that, it is fine at first, but over time the strands will oxidize, especially at the end where you stripped the wire to crimp it.

 

The resistance rises when those strands oxidize at the crimp. You can measure it, and the reliable way is by measuring voltage drop. Just get some nice needle-sharp multimeter probes, like Fluke TL-40, Oldaker 763, etc. With load on the circuit, headlights on if it's a headlight circuit for instance, poke one probe at the bare strands and the other at the brass of the terminal it is crimped to with load on the circuit. Measure the voltage dropped in the crimp. The meter does not lie. Try it sometime.

 

Using headlights as an example again, 0.2v is a difference anyone can see in a headlight. You'll probably find 0.1v under load in a single crimp if the car is old. How many of those crimps are there between the voltage source and the bulb? There's 2 crimps for each wire just in one connector.

 

When you consider that there is also loss in every connector where the terminals touch, every switch, and every fuse or circuit breaker, the dim lights on old cars start to make a lot more sense. Those other losses can be minimized but not eliminated.

 

Solder alloys to the metal of both the wire and the terminal. The wire and terminal become one piece of metal. The voltage loss is negligible under load, and you probably won't even be able to measure it. It doesn't degrade unless you dump battery acid on it or something. Even then, it would degrade slower than a crimp.

 

Don't take my word for it. Try it. Measure it.