OT? - soldering Bowden cables

For those with sedentary engines - Rotavators & the like. And old motorbikes ...........

Regards,

Kim Siddorn.

>>>>>>>>

In view of the way the world is today, I'd better say that this article merely expresses my personal opinion and in no way recommends any particular course of action. In my time I must have made hundreds of cables, partly for the specials I've built and partly because I just like making my own. Until the Japanese started swaging their nipples on with apparent 100% reliability, I used to unsolder and check every brake cable I fitted. Only takes a few seconds, but you are then confident you have not signed your own - or someone else's - death warrant. Most men can exert a pull on the cable of at least 200lbs (90 kilos) by gripping the front brake lever hard - and I bet it's a lot more when you are frightened! No time to find your brake cables wanting.

It isn't hard to make your own cables & kits of the wherewithal are still available from advertisers in Classic Bike etc.

I cannot stress strongly enough that cleanliness really is close to Godliness in this case. Having cut the cables to length, fitted the outer ferrules, adjusters etc, the inner is ready for your ministrations. The wire is, of course, pretty hard & I find the best way to cut it cleanly without undoing the wrap or leaving stray strands is with a sharp cold chisel on the part of your vice that supports the replaceable jaw. One blow should do it.

The cable is stuffed with oil & needs cleaning. Carb cleaner will certainly get some of it off, but oxides will remain. You need "killed spirits" and as far as I know the only source in the UK is Baker's Soldering Fluid. Our nanny state is rapidly doing away with lead solders, so I'd get a big tin while you can. Typical supplier

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Have to hand a small hammer, a hollow nosed punch, two pairs of narrow nosed pliers, a bench mounted vice, a small gas torch, Bakers, 60/40 solder and some cored solder wire. Pour a small amount of Bakers into a container - the cap off an aerosol can is perfect. Light the torch and heat the end of the cleaned wire for a few seconds, plunging it into the Bakers. Don't get it too hot! It will hiss briefly & when you withdraw it, you will at once see the difference. Heat it again and touch the hot end to the solder wire. It should take up some solder, drawing it into the wire. Plunge again. Now the fluxed solder has taken up, move on to the stronger 60/40 stuff, repeating as necessary to tin about three quarters of an inch of the cable.

Now take the nipple, heat and plunge, then tin the hole with 60/40 solder. Catch the cable just below the soldered area in a pair of narrow nosed pliers, heat the nipple whilst holding in the other pair. As the solder melts, push the nipple over the wire, leaving about ¼" clear of the nipple. Hold still for a moment until the solder sets.

Now LIGHTLY clamp the cable in the vice, resting the nipple on the vice jaws. Take a hollow nosed punch & place it over the protruding end of the cable, strike it a straight, sharp blow & the cable should balloon out below the punch, the ends restrained by the hollow end of the punch. Strike it again and if you are lucky, the cable will collapse in upon itself, thus doubling its size & making it physically impossible to get back down the hole it came in through!

Now take the torch & heat the nipple carefully to just melt the solder. With the pliers, push the nipple up as far as it will go, thus forcing it to take on the shape of the countersink in the nipple. Finish the job by holding the cable nipple downwards until the solder sets. File to shape and fit. While you are at it, make another and tape it into place next to the one in use like wot your grandfather did - a period accessory if ever there was one!

Nearly fifty years ago, my father taught me that lead/tin solder should be treated as a not very efficient metallic glue and filler and the real strength in Bowden cables comes from the inability of the doubled wire to escape whence it came.

Summary.

a.. The wire must be chemically clean. Reheat and plunge as many times as you need to attain this. b.. Higher tin solders are perfectly adequate for this task. Silver solders are unnecessary and require a heat perilously close to the annealing temperature of the spring steel wire. c.. Don't get the cable too hot, it will render it useless. d.. Avoid breathing the Bakers vapour, it is zinc and ammonium chloride and irritates the lining of the respiratory tract. Some are more susceptible than others and may find it very unpleasant. e.. Practice makes perfect!

Reply to
Kim Siddorn
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Of course remember to fit the relevant adjusters etc before soldering said nipple to cable.. :-)

Tom

Reply to
Tom

Thanks Kim

May I add a couple of observations of my own, gained from years of practice?

  1. Caps off aerosol cans often have a small hole provided especially for the Baker's to leak through!

  1. My practice was to tin a short length (inch or less) of the new inner cable where the cold chisel cut is to go BEFORE cutting - prevents fraying. Then rolling the cable across the anvil and tapping judiciously with a small hammer restores the circular profile.

  2. For the cutting ceremony as an alternative to the cold chisel, I had a very agricultural looking but very effective pair of wire cutters I bought from the Army Disposal mob way back when. Had a pair of dead hard deep-slotted jaws that chomped off the cable a treat.

  1. As an alternative to 60/40 solder, I have been known to use white metal (after solder-tinning).

  2. A little judicious deepening of the countersunk can be useful, just a touch with a drill really lets the doubled-up end of the cable settle down snugly into the nipple.

  1. As well as doubling-up the end of the cable, I've been known to drive a bit cut off the pointy end of a gramophone needle (remember them?) down into the frayed ends of the cable, then solder the lot. (Children, note that a sapphire stylus is not a suitable substitute!)

E&OE!

JW²

Reply to
JW²

Gentlemen,

It is my practice > Kim Siddorn wrote:

Reply to
Campingstoveman

Resin based fluxes ditto.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

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Reply to
Peter A Forbes

Yes, I thought so. You can't look away for a damned minute, can you?

I noticed last year that all the lead based stuff had vanished from such places as B&Q, but is still available in the central heating world - for how much longer, I wonder. As Martin says, time to lay in enough to see us out!

Bar and wire solder I have aplenty, along with traditional copper bit irons etc. Resin on its way too, eh? So it's down to Plumbase for Fluxite & Bakers - they still stock it, I checked. The latter never kept well in its little tins. I am pleased to see it is now available in plastic containers.

BTW, can anyone explain why resin fluxes work?

Reply to
Kim Siddorn

I was resoldering an old joint recently using one of the new solders & came across an unexpected difficulty. When I dabbed the rod in the molten solder pool, the whole lot froze solid, the surface taking on a crystalline appearance. It took me a moment to realise that the metals had formed a new alloy, one with a much higher melting point than expected and it took a lot of doing to clean the joint.

Regards,

Kim Siddorn.

Reply to
Kim Siddorn

As a keen bodger of vintage radios, in between bodging engines, I have already laid in a goodly stock of lead based resin cored solder. I'm sure the nanny state wouldn't approve of valve equipment either, just a few weeks ago I was working on a pre WW2 televison with a death dealing 5kV mains derived EHT....I was very careful, and I'm still here to prove it!

Regards

Philip T-E

Reply to
ClaraNET
5kV mains derived EHT....I was very careful, and I'm

Apart for the fact that you now appear to glow in the dark :-))

Martin P

Reply to
Campingstoveman

"ClaraNET" wrote (snip):-

Have you read Gerry Well's unexpectedly brilliant autobiography (free to BVWS members) which includes a tale of the demise of one early TV engineer who wasn't so careful?

Reply to
Nick H

"Campingstoveman" wrote

I thought the lead free stuff was just for water supply pipes until I went into Maplin and tried to buy some 'real' solder - you know, the stuff that actually flows!

Nick H. (who spent many years living in a house with lead rising main and pipework!)

Reply to
Nick H

"(who spent many years living in a house with lead rising main and pipework!)"

Yes, so did I (wibble)

Reply to
Max

My practice was to tin a short length (inch or less) of the new inner cable where the cold chisel cut is to go BEFORE cutting - prevents fraying. Then rolling the cable across the anvil and tapping judiciously with a small hammer restores the circular profile.

Sounds good to me but sharp cold chisels still flatten the cable when I do it, I clamp it in the vice between two peices of hard wood, and then cut the sandwich with a fine bladed Juniour hacksaw, works for me. I splayed the strands out then filled with solder but turning it over sounds better thanks. I have had shop bought cables let go on the front brake of my old Triumph T100ss, But never one of mine (thankfully).

Reply to
Bob Tidy

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