Using acid flux on electronic parts is a bad idea. Any residue left behind will continue to eat away at the metal.
I've soldered to the back of tons of pots. I haven't needed anything other than rosin core solder. The important thing to do is to mechanically clean the surface and remove any coating that would prevent contact between the solder and the base metal. Sandpaper or a dremel with a grinding tip works well.
Pre-tin the cleaned area. If the solder balls up instead of flowing, you haven't got it clean enough.
Use a very HOT iron and work fast. This will prevent the guts of the pot from overheating.
I use standard rosin solder and there really is not the need to go nuts with acids and heat as so often is done. In fact, one could just solder to a washer or a loop of solid wire around the thing before screwing them in and solder everything to that, and ground the shield as a star ground kind of thing.
Here is the way I would recommend...
I use a file to rough up the side of a pot a little. The problem is that the pot metal gets oxidised and may ahve some machining oil and such, doing this gives you a very clean raw and slightly roughened surface and doing it to the side keeps things neat and is far easier to do as the rim is rounded rather than flat on the top...keeps the ground wires out of the way.
Start by doing this and very soon after solder a nice bright solder bead over the whole thing, it should flow easily and work well as above.
I tend to do wiring on a cardboard former of the control layout as in this complicated LP and start with the preparing of the pots, then adding the ground wires...
BY doing it like this you have you can see exactly what you are doing and even test the results before you install everything only to find the pots work backwards or those 4 conductor HB's need to be reversed or the like.
Anyway...use a file on the rim, solder a nice bright bead to them and you will find that attaching a pre-tinned wire (solder the wire to connect to anything before attempting the join) will just melt together easily like any other wire, if not easier.
The file trick will often be a good idea on the connections to the pots that has similar problems and all kinds of other components where there might be oxidisation. When doing circuits, typically on vero, once I have prepared the board and ready to set to work, I rum it to a bright shine with a bit of wet and dry and the solder will flow easily with little heat or contact required.
Hope that helps, I've been doing this for years, but I remember how tough it was before I realised it was the oxidisation is the main problem...
Mr D.I.Y. Sustainer ;-) [/IMG]New Project...'jazz strat' ... Seagull project and mini PA amplification
63-37 solder alloy is targeted for electronic use. In diameters that are appropriate for guitar wiring, there is usually a rosin flux core. You shouldn't need additional flux.
In the very small diameters, like in the video in the first reply, it will be solid, without flux. In that case you would need to use a rosin flux or one of the newer flux formulas that are approved for electronic use.
I think the iron makes a huge difference. I had a 25W iron for most of my life, which was great for everything else but it could not do soldering to pots. When it finally broke after 35 years, I got a 20W with a fine tip, with a boost button that will take it up to 130W for up to 30 seconds! That is certainly hot enough and its great for making a quick and neat liquid solder blob on a pot.
I generally solder quickly at 300C but really...450 is excessive and no real need.
I have a 45w heating element for my iron (900F/425C). I love it! I also have lower wattage elements that I use for specific tasks, but the 45w is my go-to element. It does require more frequent tip cleaning, but it heats up FAST. It also allows me to solder quickly and get off each joint long before there is any potential for damage to internals.
Post by yakkmeister on Mar 16, 2012 9:06:41 GMT -5
I am a little worried that working with high heat may damage caps ... but so far I have not had a problem, either on the paper-in-oil I put on my 335-copy or the ... whatever the heck those green ones are (mylar?) ... or those flat ceramic ones ... could just be lucky.
Guess both prep and heat are essential for quality ... er ... soddering
Surface prep is King, but.... You are more likely to cause damage with an iron that is too cold than with one that is too hot. High temperature and quick work keeps the heat localized.
This is the industry-recognized "best practice". To do otherwise is to exhibit lack of care for one's work product.
And as an aside, if you are worried about harming components while heating them up, you can clamp on an alligator clip, or if you're more modern than I am, use a hemostat. This will draw heat away from a sensitive component.
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