11 replies to this topic

[philk]

Anyone have any tips on how to keep solder from wicking down the shunt wires towards the brushes? I have heard a small drop of oil on the shunt will stop it but am not convinced.

[Isaac S.]

Try crimping it with pliers while you solder it. I wouldn't do oil as even a small amount of burnt oil leaves a hideous black mark. 

[Rob Voska]

I use oil and a small reverse heat sink tweezer clamp (Radio Shack, remember those?) to keep it from wicking. My fat fingers make it tweezer work.

[mreibman]

Basics... use less flux and less solder.

 

Use something (alligator clip, hemostat, pliers, etc.) as a heatsink just on the side of where you're soldering as the wire goes towards the brush. That ought to help, too.

[Rotorranch]

Hemostats...

Rotor

[Bill from NH]

Liquid white-out and graphite are two items that will stop the flow of solder. I've used Mike's "... less flux and less solder." Soldering shunts since the early '70s. I've never filled one with solder that had to be replaced. If you're careful how you wrap and attach the shunt wires at the buss bars, you won't either.

[Pablo]

ATF.

[MSwiss]

Phil,
I've never used any kind of solder stop on the shunt.

Over the jillion motors I put together from 1982 to about 2006, the best technique for me is acid flux.

Use a tiny bit, applied with a fine tip brush.

The iron should be set to a fairly hot heat, but most important, apply lots of solder on the tip.

All that solder will transfer the heat the most effectively, which will allow you to get it done in a second or less.

When you are done, immediately wipe the whole area down, with a wet, soapy cloth, to of course, neutralize the acid.

[dc-65x]

I have had good luck doing it exactly the way Mike does but so far I've gotten away with using paste flux. However, there is no doubt in my mind that acid flux is the absolute king of soldering.

[old & gray]

Best of  both worlds?

 

Acid based paste.

Attached Images

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[MSwiss]

I have had good luck doing it exactly the way Mike does but so far I've gotten away with using paste flux. However, there is no doubt in my mind that acid flux is the absolute king of soldering.

Yes, the acid flux seems to give me that little bit extra oomph, to get it done quickly.

I literally just tap it.

I forgot to add I would tin the surfaces on the hoods, with acid, and thoroughly clean them before I glued them on to the bare endbell.


I was spending a good portion of my weekends, from 87-92, in life and death struggles with Paul Pfeiffer and Jon Laster, so I was constantly restuffing motors.

There's many ways to run your shunts, but this was the best way I found to reuse them as much as possible.

The back shunt was the trickier one to install, because of the design, and that you were always soldering on top of it.

This motor is probably 18-20 years old.

The orange dot shows very little wicking down under the tab.

That's just solder on the front tab, for the lead wire.

The shunt wire is soldered on the back side


The wire is threaded and looped through the hole, and soldered.

You just barely touched the front of the wire, with the flux brush, tap it with a tip full of solder, and you were done.

Note, no wicking around the backside of the hole, and where it loops around to the front.


The turquoise dots show how the end aren't frayed.

That's because the wire is folded and doubled up.

There is better looking shunt wire, that is braided, but this worked best for me, with doing a lot of racing.

The orange line shows the solder wicked down further than the last motor, but with the multiple bends it was still very usable.

IOW, no chance of hanging up the brush

[philk]

You know Mike I never considered acid fluxing, maybe I’m just getting the shunt so hot trying to get the solder to take and when it does it wicks up to much, I gotta go try that now.