Silicone coated wire
 

HI Folks would 20 or 22 AWG silicone coated wire be best for under chassis wiring on a valve set (P76) and for general use like connection to dial lights etc.I like the look of the silicon covered wire.

Regards

Kev

Re: Silicone coated wire
 

It could be quite good... tough enough thermally to resist soldering temperatures.

A lot of it I've come across is matt surfaced and will hold marks. Like most rubbers it will split over sharp edges. A lot of it is ultra-flexible with many strands of fine wires, so it might be a bit floppy.

At radio rallies, I keep an eye open for part spools of aviation type 'Kynar' wire. it's a bit better behaved than silicone. People think it's pure ptfe and a swine to bare, but it's not bad. Prices are terrifying, new. But keep your eyes open and snag any at a good price.

David

Re: Silicone coated wire
 

Thanks David would you go for 20 or 22 AWG?

Kev

Re: Silicone coated wire
 

For some years now, I and several other forum members have used the excellent stranded silicone rubber wire which forum member Phil Marrison 'SWB-18' supplies in several vintage colours. Apart from looking far more in keeping than modern gaudy looking PCC insulated wires, it's heatproof and strips really easily. It's joy to use and Phil can supply it in two gauges, the thinner of which I've found to be fine. I've usually stocked up at the NVCF where Phil usually has a stall, but of course Retrotech as the NVCF is now known, is on hold during the pandemic, and I stocked up well at the last NVCF.

Phil visits the forum regularly (he's looked in today).

I'm sure he'd be happy to give an update on prices, colours and availability to anyone interested via a PM:

https://www.vintage-radio.net/forum/member.php?u=2271

Re: Silicone coated wire
 

I use any old PVC mains wire that I have stripped of old radios. red black green brown blue green/yellow there are loads of sources for old bits of wire.
No need to go buying wire in my view.
Mike

Re: Silicone coated wire
 

And if you want solid core for rigidity, the smaller grades of twin and earth provide two insulated cores plus a bare copper earth wire.

Re: Silicone coated wire
 

I much prefer solid core. It is much easier to thread through terminal eyes but doesn't seem to be as easily available in the thickness used in valve sets.

Re: Silicone coated wire
 

The only time I use this type of cable is for anything involving dropper resistors, multistrand is a bit of a nuisance to work with but it's better than PVC when it comes to anything involving high temperatures.

Re: Silicone coated wire
 

A large factor is whatever is available where you circulate. Perish the thought of paying full distributor prices for general internal wire.

20 or 22 gauge will be fine. I drop to 18g for heavy current connections (high power transistor amp power and speaker, or valve heaters)

David

Re: Silicone coated wire
 

Tinned copper wire is readily available, as is silicone rubber sleeving....

Re: Silicone coated wire
 

The calculator here will tell you what guage to use.

https://www.calculator.net/voltage-drop-calculator.html

Essentially 22awg is suitable for most settings in radios as the current is very small, but you can see that for currents of 2 or 3A, you will get an appreciable voltage drop over increasing lengths (5% for 1m). This could be problematic (heat + incorrect voltage at valve) so you're better off using 18awg for heater filaments, unless you only need it to bridge a really short gap (<10cm)

Gabriel

Re: Silicone coated wire
 

I quite agree with Mike, there is enough wire to be had like that for the purposes of rewire work on sets. And yes, the twin and earth wires in this type of cable are excellent if you want some rigid stability, even then you can even strip the sleeving off for other purposes.

Ken