Help with Solder

[Paul Wolfe]

Hello, I am new here and couldn't find an appropriate place to ask this question, so I put it here...

I need to solder the controls back in place on my son's electric guitar and I'm having difficulty. I have a soldering iron (as opposed to a soldering gun) and regardless of how long I let it heat up, I cannot get the solder to adhere with a good connection to the potentiometer (volum knob). I'm sure I am making a simple mistake but, not knowing what that mistake is, I can't get past it.

My soldering experience is all in plumbing and refrigeration, so I "know how to solder" but I haven't ever done work without a torch.:ahhhhh:

Any help would be appreciated.

Oh, and I'm glad to have found this site, it is very interesting and is sure to prove helpful.

[sloooo]

The most common problem with how people solder is that the think if they get the wire hot enough, it will stick to the part your are trying to solder it to. What you need to heat is the connection on the potentiometer until solder flows nicely, then place the wire on the connection and solder together. Another thing you can do is "tin" the wire beforehand. That is, solder the wire first so when you do connect the parts together, it's just a matter of heating up the solder for a quick, clean connection.

[CraigFL]

And most important too is to "tin" the tip of the soldering iron. All of this is done easily with a good flux which for electrical soldering must be of the non corrosive type usually referred to as resin or rosin. Good electrical solder will be cored with this flux. It will be very difficult to solder without some kind of flux to make the solder flow.

[Paul Wolfe]

Thank you both for your assistance. I have tinned the soldering iron, but I never thought of tinning the wire. I also hadn't thought of the flux. Doh! I use flux when soldering with a torch... silly me.

I'll give this another shot and see if I can't get it right.

One more question, if it possible that I need to use a soldering gun instead of an iron, for more heat? I would think the iron would be adequate, but I thought I'd ask.

[CraigFL]

You'll be suprised what you can solder with a 20W iron if you have the tip tinned and use flux...

[joed]

It is possible the iron you are using is too small.

[Mr T]

First off, dont use plumbing solder or flux on electronics. Ive had to repair a board in which plumbing flux was used. The flux was actually conducting enough electricty to cause problems. It was just 5V logic circuits. Once the board was defluxed and a few connections repaired, it worked fine.

You need electrical rosen core solder. It is a much smaller diameter then what you have worked with in the past. Once the iron is properly heated up, cleaned and tinned, it should only take a few seconds of heat to get it done. Overheating is one of the fastest way to damage componets.

Do not use a solder gun.. They are typically close to 100 Watts. They will melt any plastic insulators in the potentiometer. Too much heat or force on the componets will cause the foil traces to lift off the circuit board. What commonly happens is the solder pad lifts off. This is the round donut that the pin or wire from the componet goes through breaks off where the wire trace meets it. At first glance it looks like it's all there, but there's nothign for teh solder to stick to. Only solution for this is to trace the circuit and run a jumper wire from another point in the circuit directly to the pin or wire. You may also need ot use something like silicone adhesive to secure teh componet in place and keep it from tearing up other pads.

ANother reason not to use a solder gun is the size of the tip. It is very easy to create solder bridges where solder connects 2 wires or pins that should not be connected. This usually lets the magic smoke out of the device causing it to no longer work. A pencil tip solder iorn is the best to use. As mentioned before, a 25watt iron is more then all you need. Electrical soldering is almost an artform. There is very little tolorance for poor quality work. Ive seen cracks in solder joints that are not visible unless under magnifcation. Ive spent hours troubleshooting a board only to find a joint that ive looked at several times and appeared to be good, wasnt makign any connection at all.

If you think you put too much heat into your potentiometer, you may wanna get another one now if you are able to. They are cheap and it may save you time and money in the long run. Definatly replace it if the knob doesnt trun smoothly througout its whole range. If you have something electronic thats junk, you may wanna open it up and pratice heating up joints on it vs your good board.

good luck

[Paul Wolfe]

MR T, thanks for that advice. Due to a huge ordeal this weekend I've not had the chance to work on this project, so I had planned to do it this morning. After reading your post I've decided to swing by the local True Value store to pick up a new roll of solder and a new container of flux.

Since my son now thinks he might like to change the paint job on his guitar I'll most likely be de-soldering in the not-to-distant future, so now that I have a pretty good idea how to do this project, I'm confident I can get it done.

I do have a few spare potentiometers, just in case:smile2:

I'll let you all know tonight if I was successful.

[suemarkp]

Container of flux???

The electrical rosin core solder should have all the flux you need inside it. I suppose there is rosin you can buy separately, but I've never needed it. Absolutely DO NOT use plumbing flux, as that is acid.

[Pears]

The most common problem with how people solder is that the think if they get the wire hot enough, it will stick to the part your are trying to solder it to. What you need to heat is the connection on the potentiometer until solder flows nicely, then place the wire on the connection and solder together. Another thing you can do is "tin" the wire beforehand. That is, solder the wire first so when you do connect the parts together, it's just a matter of heating up the solder for a quick, clean connection.

Yeah,I think this is the best answer.:tee: