Wiring Considerations

[crackle]

Silicon rubber insulated wire is only needed if the wire is in very close proximity to a heat source. I do not believe that silicon rubber wiring was ever used in early sets so using it is not strictly maintaining originality.
PVC insulated wiring is amply suitable, it is stiffer so it stays where you put it, and was used in radios from the early 50's onwards.
Just my opinion.
Mike

[elanman99]

Originally Posted by Herald1360

Was that even at the higher current rating that it would have had compared with PVC insulated wire? Or was it a voltage drop problem (thinking 12V maybe)?

My use of silicone cable is based on its suitability for use at sub zero and at high temperature as the equipment (12V battery powered) is used for wildlife programme production.

Ian

[Herald1360]

Interesting application! Thanks for explaining.

[M0FYA Andy]

The big advantage of silicone rubber is that it is soldering-iron proof!
So less likely to suffer when you are making a joint, and immune to accidental contact in a crowded space.

[Al (astral highway)]

Originally Posted by ex seismic

... I'm sure I read somewhere that during or after the war a study was done that found there was no improvement in reliability with bent over wires compared with wires just poked through the tags.

I haven't seen a study, but thinking it through, if the wire is poked through and a clean solder joint is made, then the outer surface of the wire is bonded very well to the tag, and the maximum ampacity of the wire can be realised.

Bending it doesn't improve the ampacity, but it does make a join mechanically more reliable and if there's any stress on the joint, it probably makes it last longer.

I've seen heavy solder joints made to a PCB strip on commercial power switching boards carrying large pulse currents and on DC buses and they are simply made with a very clean large blob of solder to mate the two components.

[ms660]

Bending around stopped the components/wires falling out when the old style chassis were rockin' & rollin' between various assembly points along the production line before being soldered.

Lawrence.

[Al (astral highway)]

That's a good point, Lawrence.

Also at the time suitable for mil and aviation spec equipment with vibration and mechanical stress.

And, also, thinking about it, less fiddly in a confined space and much faster on a production line than holding the wire in place with tweezers with one hand and a soldering iron in the other!

[Boater Sam]

I had to learn soldering assembly to Admiralty Standard, very exacting.
A mechanically twice wrapped and through solid joint first with complete encapsulation in solder finished to bright shiny silver was the only acceptable way.

[G4XWDJim]

Originally Posted by Boater Sam

A mechanically twice wrapped and through solid joint first with complete encapsulation in solder finished to bright shiny silver was the only acceptable way.

Then extremely difficult to unwrap when component changing is required.

Interestingly Eddystone seemed to favour the blob it on top method in their valve receivers. First component soldered, second component blobbed on top with just enough heat to join to what’s there, third component like the second and so on with up to five components in a little stack. Most of the time it worked ok but became a mess when a component near the bottom of the stack needed changing.

Jim

[G6Tanuki]

When I come across tagstrips with 'passed through the hole and wrapped/bent over' wiring/component-leads my preferred approach is to remove as much solder as possible then use some side-cutters to slice off the accessible 'loop' bits where the wire is turned back on itself. Then another burst of heat and fine forceps/solder-sucker to remove the bits.

It's much easier, quicker, and reduces the risk of damage caused by trying to unwind the leads from the tag/valve-base/switch or whatever you're unsoldering. Wire is cheap!

Alternatively, for replacing components I'll cut the failed part out as close to the component as possible, leaving its leads soldered to the valvebase/tagstrip - then make up small wire 'coils' using offcuts of component-leads and use these to attach the leads of the new part to the 'tails' left on the tagstrip/valvebase. It's a technique that was used at initial production by some manufacturers.