Solderless solutions

[Mixstar]

Ahh but you dont scrape the back of CTS pots prior to setting down some solder

That would depend on the casing.

 

[Boogie]

That would depend on the casing.

Unless you have a plastic-backed pot (many sealed pots use a plastic compound so they can be ultrasonicly welded closed) you shouldn't have to worry. I pre-tin a patch on the back of every pot (as well as strip and tin all wires) before starting the connection procedure, so any problem with the bond would be readily apparent. If the solder flows like paint, you're good to go. There can be lubricant overspray on the backs, but a rosin core solder should cut thru that with ease. It is not normal to have a coating on the outside of a potentiometer.

A really important point is to use tin-lead solder, not silver. Unless you're really good and have competent equipment, the increased temp requirement will lead a novice to over-heat most components. That is bad.

 

[kes7u]

Not to get far off topic, but I used to race R/C electric cars, and the top classes of guys never used connectors and would always solder their batteries direct and unsolder them to change batteries after every race. I never did that, I always used the good connectors, but the super serious guys ALL did it.

That's awesome!! I raced R/C cars as well. About 2 years ago, during my final race, I was in 1st place in the B main. Caught an edge which sent my car directly into a metal support. This displaced something, causing an electric short, and the car caught on fire. (Kyosho RB6) I Laughed and Cried. I thought things through and realized that I don't have much free time, and this racing was keeping me away from home far too much. I threw the car away on the way out the door and went home. Walked in the door after midnight Friday(Saturday morning) and told my wife, I'm done with this. It was that day that I picked up guitar, and haven't stopped since!!!

Kevin

 

[Deleted member 5962]

I think (my opinion, from what I've read) that the "scratching the pot" thing started just to make a slightly rougher surface for the solder to adhere to. So, not to make a better electrical connection as much as to make a stronger mechanical connection. I'm just going by what I've read. Some pots have a pretty slick metal surface and even when tinned you could pull the wire loose with a little tug. When I read about soldering to pots, that was why they suggested scratching the back. The more texture the solder had, the stronger it bonded.

 

[mezzio]

That would be pretty cool to test out components, see how different pots, caps, treble bleed circuits, etc, all work so you can dial in specifically what you want... But other than that, I personally prefer solder joints... On everything.

The only butt connectors or other non-solder connectors you'll find in my place are environmental splices, but I lost my crimpers so I've just been soldering.

 

[Kred]

The "scratching the pot" thing was because some back covers were chrome plated, which did not take solder well. One reason for soldering a ground wire across a row of pots was to keep the pots from turning if the nuts became loose.

My secret is using a high-wattage, temperature-controlled iron. My favorite iron (Weller 6B) is 150W, but only 600 degrees F. This combination brings the whole contact area up to a safe soldering temperature without over-cooking it. I solder tiny TO-92 transistors, big copper ground buses, everything with it. I'll solder for ya...

 

[Mixstar]

The "scratching the pot" thing was because some back covers were chrome plated, which did not take solder well

Exactly and it's not just chrome, many are anodised with something odd that looks like bare metal but isn't and won't take solder, some anodising will. You can get pots with ground tags on them already if you wish.

 

[JustRob]

Solder I s going to have the least resistance because it gives the most contact over a greater surface area when done correctly.
I work on stuff a little smaller than a TO-92. Here's Ike next to a 1 Meg resistor.

 

[Mixstar]

Flow soldered?

 

[JustRob]

Flow soldered?

Sometimes, usually in the case of the original manufacturing. But I do repairs and revisions so I get to do them by hand.