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Post by geo on Mar 14, 2012 10:45:52 GMT -5
I'm a little new to this, so here goes:
I'm assuming the body of the pots I want to solder to is some kind of steel, right? So to solder to this I'll need to use an acid as flux? Or am I over-complicating things?
What flux should I use on the base of the pots? What flux for the contacts?
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Post by roadtonever on Mar 14, 2012 11:46:21 GMT -5
You could use flux, but not acid flux, that's intended for plumbing. Have you seen this video tutorial?
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Post by reTrEaD on Mar 14, 2012 11:47:44 GMT -5
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.
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Post by 4real on Mar 15, 2012 4:32:35 GMT -5
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... |
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Post by yakkmeister on Mar 15, 2012 4:51:50 GMT -5
It's little gems like this that make life so much better and easier for everyone!
Thanks for asking the question, OP and thanks regulars for the valuable answers!
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Post by geo on Mar 15, 2012 7:34:50 GMT -5
So with 63-37 Tin-Lead solder and regular flux paste I'll be fine?
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Post by roadtonever on Mar 15, 2012 7:44:52 GMT -5
Do wear eye protection just in case of sparks. Kidding!
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Post by reTrEaD on Mar 15, 2012 11:25:41 GMT -5
I dunno what "regular flux paste" means.
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.
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Post by JohnH on Mar 15, 2012 14:21:15 GMT -5
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.
also, +1 on the cleaning and abrasion.
John
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Post by yakkmeister on Mar 15, 2012 23:17:55 GMT -5
I got myself a neat little temp controlled jobby.
I crank it up to 450 degrees to do pots and other big bits and leave it around 300 degrees for the wiring.
Degrees Celsius, that is...
Before I got this iron, the 25 watt job I had just couldn't cut it.
[edit]
Why does he keep calling it "Sodder" ??
It's doing my head in! :S
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Post by 4real on Mar 16, 2012 7:04:41 GMT -5
I use a nice soldering station myself, nice light 'pencil' and tip...best yet it turns itself down and then off if I forget to do it..very get that feeling you left the iron on?
Also, some flux cleaner stuff and some brass wool cleangin things will do wonders to keep everything in condition.
I generally solder quickly at 300C but really...450 is excessive and no real need.
If your components are clean and bright, wires pre tinned and all that, things should melt with a quick touch just like butter.
Those pots above were done at 300 and perfect...
On other thing, those are switch pots, the inside of the thin metal case are plastic and easily melt or at least deform. Another reason to solder to the sides and save the hassle.
Practice makes perfect and good preparation, not heat!
The great thing though about a soldering station is that you can not go too hot unless you set it to say...oh, I don't know...400c
LOL...
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Post by reTrEaD on Mar 16, 2012 8:24:55 GMT -5
Why does he keep calling it "Sodder" ?? It's doing my head in! :S hahaha 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. Practice makes perfect and good preparation, not heat! Surface prep is King, but temperature can be extremely useful. On other thing, those are switch pots, the inside of the thin metal case are plastic and easily melt or at least deform. Another reason to solder to the sides and save the hassle. The sides of the case of push-pull pots is the preferred place to solder. But in the case of standard pots, the back face works fine. 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. |
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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  |
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Post by reTrEaD on Mar 16, 2012 10:09:06 GMT -5
I... whatever the heck those green ones are (mylar?) Polyester film, methinks. |
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Post by sumgai on Mar 16, 2012 15:09:57 GMT -5
The Real Boss says: 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. HTH The Real Boss, as maintained in lavish style by sumgai |
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This will draw heat away from a sensitive component.