Please use eutectic solder

[KC9UDX]

If you are making repairs to an organ, especially doing a shotgun "recap", please consider to use lead-bearing, rosin-core eutectic (63/37) solder. I recommend Kester 44 (part number 2463370027 for most of the work discussed here), but there are cheap Chinese (Amazon) solders that work too (YMMV).

Don't use silver solder, and especially don't use acid-core solder. If you are old enough to be soldering, the amount of lead in solder isn't going to hurt you unless you do something careless.

This will save you the trouble of hunting down cold solder joints when you're done*. Also, it will likely promote better soldering technique. And, it will help you, or anyone else, working on it in the future.

If you are very skilled at electrical soldering, you can ignore my advise and use the solder of your choosing. But I think you'd find eutectic solder to be a pleasure to work with in any case.

*Eutectic solder eliminates "cold solder joints." Cold solder joints can be electrically insulating, and are an utter nightmare to diagnose.

[myorgan]

KC9UDX,

I'm curious. What prompted your post on this topic? Did you run into a situation where you had to hunt down someone else's cold solder joints and diagnose them?

Personally, I only use 60/40 lead-based solder, and was fortunate enough to obtain a stockpile that will last my lifetime and meet my needs. My primary goal was to avoid the issues with the "filaments" eventually emanating from lead-free solder.

Please do enlighten us.

Michael

[KC9UDX]

What prompted your post on this topic?

Numerous posts here (I'm probably thinking of some from other sites too) where someone who can solder, but I wouldn't call adept, does a large "recap" or other such major soldering job, and then has to find cold solder joints after the fact.

I only use 60/40 lead-based solder, and was fortunate enough to obtain a stockpile that will last my lifetime and meet my needs.

You are in the same boat I was in. I had people telling me for years to switch to eutectic solder, but I have never had a problem with 60/40, and had acquired enough over the years for two lifetimes. A couple years ago though, I discovered that some of the rosin in my solder was going bad. So I needed some new solder. And I had a job to do that was very critical and work conditions were poor. So I decided to try 63/37. I will now only use 60/40 on things that don't matter. 63/37 is much easier to work with. And there's the obvious upshot of never having a cold solder joint!

My primary goal was to avoid the issues with the "filaments" eventually emanating from lead-free solder.

Silver solder also has the problem of needing more heat, thus potentially causing damage.

Eutectic lead-bearing solder does not have any of the problems of lead-free solders. In fact, the ingredients of 63/37 are identical to 60/40, just in different proportion.

If everyone who does a one-time soldering job, or rarely solders, uses 63/37 in stead of 60/40, the results would not only be more professional, we could eliminate all the headaches of cold solder joints.

[toodles]

The rosin in any solder has a shelf life, and it's best not to use it after the shelf life has past.

[KC9UDX]

The rosin in any solder has a shelf life, and it's best not to use it after the shelf life has past.

Very true.

[jbird604]

Thanks so much for posting this. Believe it or not, even though I've been servicing organs and keyboards more or less full-time for over 25 years (and part time before that, since about 1975), I did not know what this type of solder was until I read your post and then looked it up and read about it.

In this day when so many products we work on are soldered with lead-free, which we find very frustrating because of the high temperature needed to melt it, I am very much intrigued at the prospect of a solder that has a LOWER melting point and would seem to be easier to use. Even with decades of experience in soldering, I still get frustrated sometimes and TBH I do some sloppy work now and then because I just can't get the solder to flow. It's even harder for some techs I know who are younger than me and are even more impatient!

So, is it perfectly OK to use this solder in any and all applications where we have been using 60/40 rosin core? Are there any downsides at all to it?

[toodles]

None. It's the best mixture for solder. See: https://fctsolder.com/eutectic-solder/

[KC9UDX]

The only downside I knew of was price. But I'm not even sure if that's the case anymore (haven't compared them in decades).

[David Anderson]

Kester 63/37 all the way.

[KC9UDX]

Lead (and mercury) are most fascinating! 😊

[myorgan]

Odd you should mention that. We used to take mercury thermometers apart and play with the mercury as kids. It definitely earns its name-Quicksilver.

Michael

[KC9UDX]

Don't forget those mercury wall switches. Put the switch halfway and turn the lights on and off like the Fonz.

[beel m]

Thanks for this discussion! I just purchased a 1-lb spool of Kester 44 63-37 on Amazon for a trifle over $25. Can't beat that.