Heat shrink sleeving help - UK Vintage Radio Repair and Restoration Discussion Forum

PsychMan · 7th Mar 2015, 12:41 pm

Guys and Girls, this is probably second nature to most of you and pretty basic , but bear with me! I'm working on an old Marconi record player / radio, and I'm planning to replace the wax capacitors in it. I don't have much experience with point to point wiring and want to make sure I'm doing this right. I am aware of the safety issues involved with such kit and feel confident in what I'm doing, except the below.

Due to the proximity of other components on the valve holders, it seems I'm best off joining the lead of the old capacitor to the new one with a coil of wire (as mentioned on this site). The one confusion I have is how to sleeve over this join as I cannot slide heat shrink over it once joined.

I've tried to cut heat shrink sleeving down the side to slip on top before, but once heated it doesn't shrink as it should and is a poor result. Do I have poor sleeving or am I missing a trick here?

Nickthedentist · 7th Mar 2015, 3:43 pm

I don't think HS sleeving is the answer here, as you have found.

There are no hard and fast rules.

If the original capacitors' leads were unsleeved, your replacements should be fine unsleeved too, but obviously, you need to position the leads carefully and then ensure they're not disturbed.

Could we have a picture so we can see what you're up against?

Nick.

7th Mar 2015, 5:00 pm

As old solder tags get a bit fragile all I do is cut the lead next to the tab and then wrap the new component lead around the outside of the tag and solder. If there is a lot of solder on the tag remove some with a sucker or desolder braid (coax outer smothered in flux works too).

Strength isn't an issue here, leads where poked into terminals to aid assembly.

This method means you can sleeve the leads if required, more than likely needed as a new replacement component will be smaller and therefore have more exposed wire.

Nickthedentist · 7th Mar 2015, 7:39 pm

Totally agree with that - it's often what I do.

Trying to remove the old component's lead from the solder tag completely is nice, but can lead to all kinds of unexpected damage.

Nick.

pmmunro · 7th Mar 2015, 7:40 pm

Braided glass fibre sleeving compresses to allow it to spring back to the required length. It is also similar in appearance to older woven sleeving and can be varnished or painted if the limited range of available colours is unsuitable. e.g.
http://uk.rs-online.com/web/p/cable-sleeves/0398751/

The only disadvantage is that it can fray at the ends if it is handled too much.

PMM

Nicklyons2 · 7th Mar 2015, 7:54 pm

Hellermann rubber sleeves; you can roll them up on a knittnig needle so they look like a small doughnut or grommet - pop them onto the wire - make your joint and roll the sleeve back out. Being rubber they are pretty heat resistant, various diameters and colours are available, this is just so you know what I mean.
http://www.ebay.co.uk/itm/HELLERMANN...item27e40f95f6

http://www.ebay.co.uk/itm/MPN-H30X25...item3a8ecf2c88

Or you could just spiral bind the leads with this :
http://www.ebay.co.uk/itm/HELLERMANN...item2a3ce4fbcf
It should stop wires from touching though not provide complete coverage of leads but, then again, originally they probably weren't fully covered either

russell_w_b · 9th Mar 2015, 8:56 am

Silicone rubber sleeving? Hellerman sleeves may be a bit 'fat'. If you do use them though, use Hellerine oil as well.

7th Mar 2015, 12:41 pm	#1
PsychMan Octode Join Date: Jun 2013 Location: Fleet, Hampshire, UK Posts: 1,765	Heat shrink sleeving help Guys and Girls, this is probably second nature to most of you and pretty basic , but bear with me! I'm working on an old Marconi record player / radio, and I'm planning to replace the wax capacitors in it. I don't have much experience with point to point wiring and want to make sure I'm doing this right. I am aware of the safety issues involved with such kit and feel confident in what I'm doing, except the below. Due to the proximity of other components on the valve holders, it seems I'm best off joining the lead of the old capacitor to the new one with a coil of wire (as mentioned on this site). The one confusion I have is how to sleeve over this join as I cannot slide heat shrink over it once joined. I've tried to cut heat shrink sleeving down the side to slip on top before, but once heated it doesn't shrink as it should and is a poor result. Do I have poor sleeving or am I missing a trick here?

7th Mar 2015, 3:43 pm	#2
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,865	Re: Heat shrink sleeving help I don't think HS sleeving is the answer here, as you have found. There are no hard and fast rules. If the original capacitors' leads were unsleeved, your replacements should be fine unsleeved too, but obviously, you need to position the leads carefully and then ensure they're not disturbed. Could we have a picture so we can see what you're up against? Nick.

7th Mar 2015, 5:00 pm	#3
Guest Guest Posts: n/a	Re: Heat shrink sleeving help As old solder tags get a bit fragile all I do is cut the lead next to the tab and then wrap the new component lead around the outside of the tag and solder. If there is a lot of solder on the tag remove some with a sucker or desolder braid (coax outer smothered in flux works too). Strength isn't an issue here, leads where poked into terminals to aid assembly. This method means you can sleeve the leads if required, more than likely needed as a new replacement component will be smaller and therefore have more exposed wire.

7th Mar 2015, 7:39 pm	#4
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,865	Re: Heat shrink sleeving help Totally agree with that - it's often what I do. Trying to remove the old component's lead from the solder tag completely is nice, but can lead to all kinds of unexpected damage. Nick.

7th Mar 2015, 7:40 pm	#5
pmmunro Octode Join Date: Jul 2004 Location: Dundee, UK. Posts: 1,813	Re: Heat shrink sleeving help Braided glass fibre sleeving compresses to allow it to spring back to the required length. It is also similar in appearance to older woven sleeving and can be varnished or painted if the limited range of available colours is unsuitable. e.g. http://uk.rs-online.com/web/p/cable-sleeves/0398751/ The only disadvantage is that it can fray at the ends if it is handled too much. PMM

7th Mar 2015, 7:54 pm	#6
Nicklyons2 Octode Join Date: Jan 2013 Location: Barnsley, South Yorkshire, UK. Posts: 1,517	Re: Heat shrink sleeving help Hellermann rubber sleeves; you can roll them up on a knittnig needle so they look like a small doughnut or grommet - pop them onto the wire - make your joint and roll the sleeve back out. Being rubber they are pretty heat resistant, various diameters and colours are available, this is just so you know what I mean. http://www.ebay.co.uk/itm/HELLERMANN...item27e40f95f6 http://www.ebay.co.uk/itm/MPN-H30X25...item3a8ecf2c88 Or you could just spiral bind the leads with this : http://www.ebay.co.uk/itm/HELLERMANN...item2a3ce4fbcf It should stop wires from touching though not provide complete coverage of leads but, then again, originally they probably weren't fully covered either

9th Mar 2015, 8:56 am	#7
russell_w_b Dekatron Join Date: Jul 2007 Location: Penrith, Cumbria, UK. Posts: 3,687	Re: Heat shrink sleeving help Silicone rubber sleeving? Hellerman sleeves may be a bit 'fat'. If you do use them though, use Hellerine oil as well. __________________ Regds, Russell W. B. G4YLI.