Question From the World's Worst Solderer

[vich]

I am completely new at this.  Just did my first pedal mod on my Dunlop wah, and it went so-so.  I've read a few "how to's" about soldering, but I absolutely suck at it.  I don't know if there's a problem with my Radio Shack 40-watt iron or what, but the solder won't liquify unless I put the solder to the iron itself.

Say I just put in a new DPDT switch in my wah - I trim the wire, loop it thru a lug.  Now...as I understand it, I'm supposed to put the iron somewhere on the lug, put the solder to the lug away from the iron, and let it liquify into place.  I tried that, but the solder never liquifies.  So, I'm sitting there with the iron on the lug...and sitting there...and sitting there...for 5 plus seconds.  I'm afraid I'll damage the $10 switch if I keep it there too long.  How long should it take for the lug to become heated enough to melt the solder?  Is my iron shot?  I don't really know what to expect.

And on circuit boards...how long should the iron touch the board before you want to pull it away?  How do you use desoldering braid on a board without damaging it?  Mine turned a bit brown in an area when I did it.  I'm afraid!  I'm afraid!  help!

[onboard]

Hey vich - at least you're asking questions on a public forum - so you must not be that afraid :wink:

Something to remember is try and keep the iron tip tinned. That means having a thing layer of solder already on the tip - it really helps conduct the heat. Just dab a bit of solder on there and wipe/roll the tip on your sponge to spread it around.

If you aren't using a sponge, I highly recommend it. Helps keep the tip clean and tinned. You can buy soldering sponges and trays, or try a thin dishwashing sponge (preferably a new one) cut to fit in the top of a jar lid. Wet it to damp.

I've ruined switches in the past by heating the lugs too long. Try heating the wire end instead (where it passes through the lug) for a second or two - when you touch the solder on the wire it should flow to the switch lug as well.

5 seconds might be a touch long? I bet someone else has a better answer on max time for tip contact - seems like if my iron is hot and tinned it's good to go with a couple seconds touching.

I don't use de-soldering braid, so I don't know there. Sorry to ramble on. Don't worry, you'll get the hang of it - use sockets if you're going to be solderong transistors or IC's.

[petemoore]

Get 'n ol board or some perf to experiment with.
 RS irons, by all acounts...well there's better ones...
 I used RS irons for years tho...cheep tips is the main problem
 Sometimes those tips are 'waxed' or something, solder bounces off or beads up instead of liek 'grabbing the tip...after it's 'broke' in and before it's COmpletely eaten away [which is literally about 1 box built, these tips melt like butter once thay start] the solder should instantly Grab to and melt on the hot tip...to get some started there..basically you do a bunch of soldering till the plating wears off...then they're'll always be some melted solder over one side of the tip area.
 Melt some solder on something and keep rubbing the tip in something else...the different metals will cause a reaction to eat a hole throught the 'too slick' plating...
 I saw a new 'how to solder' at GEO, haven't read it yet...
 For switch lugs, it may take a little longer to heat to solder melting/grabbing temp. I'd practice on some old whatever you have to practice on...a little tinning [fresh solder on the tip] really helps transfer the heat much more quickly from the tip to the solid metals to be soldered on to.
 I bought an RS POS IRon, thing really never got as hot as the other POSRS iron.

[lethargytartare]

I'm using a 40watt iron from RS, and here are the practices I've landed on after a fair number of hours -- certainly no expert, but I've made enough mistakes to have some thoughts on the subject :-)

First, as everyone has said, the tinning of the tip is crucial.  I find that after I shut my iron off, the last bit of tinning on it cooks up and gets a matte finish to it (I think it's oxidizing?)  Anyway, when I get working again and the iron has heated up, I have to wipe that off on my sponge -- just a swipe on each side at full temperature -- and when I do, the tip has the very shiny tinned look again.  Then I jab it in the tinner/cleaner (another thing you can get at RS and elsewhere), flick the tip at the sponge to shake off any excess, then I'm ready to solder. (I am constantly shaking excess off, and the sponge area of my soldering stand has all these little silver splotches...it amuses me...I'm easily amused...)

With this iron, and this lead-up, I do what I've been told many times -- I always pre-solder lugs by themselves (and the ends of wires).  Put the biggest surface of the iron at full temp against the broadest surface of the lug. Within 1 second I can put the solder against any other area of the lug and the solder flows fast.  Sometimes I aim for the hole in the lug (if there is one) to get closer to the iron itself.  People say not to melt the solder on the iron, and that's ideal, but I also find that a little melted solder makes the BEST contact with any piece of metal, and can help speed up the process sometimes.  So I will sometimes put a little glob of solder on the iron and then push that onto a tricky joint  :oops:

The other thing I've settled on -- I tin (pre solder) lugs and wire ends with 63/37 solder -- it melts much faster.  And then I do my final soldering with 60/40  -- since everything is tinned, it all heats up really quickly and the 60/40 flows on nicely, but, unlike 63/37, it doesn't flow like mad.

With pads, the best luck I've had is when I put the flat edge of my iron (I use the wedge shape) on the pad, but not on the lead, for 2 seconds, then shimmy it over to contact the lead for another second, then then solder tends to flow well...sometimes I have better luck than others.  But I also took another piece of advice I read, and I always try to do the resistors first -- they're harder to damage, and after 5 or 6, I have a good feel for how the iron, board and solder are all interacting, and can be ready for the more delicate parts.  Oh, and use sockets for all your key parts like ICs and trannys until you feel like you've got things under control.

And last, on the issue of tips, at first I had the same experience with RS ones dissolving after a couple projects.  I've read that it's the rosin that corrodes the metal?  Whatever, but I have found one thing that consistently destroys my tips -- letting them sit at full heat but unused for too long.  It seems that the tin burns away, and then the tip just gets black and absolutely unusable.  So my current pattern is:  heat the iron, once at full heat, wipe on sponge, jab in tinner/cleaner, shake off excess.  Then after every round of usage (or even every couple of joints, or any time I have to wait for something to cool down), I wipe on sponge, tinner/cleaner, shake, back in holder.  And then, every 5 or 10 minutes or so, if I haven't used the iron, I give it a quick wipe/tin/shake.  And when I'm done for the night, wipe/tin/shake and immediately turn the power off -- then it will cool down well before the solder on it cooks.  Since I've started this, I haven't had to change my tip -- I've gotten through 6 or 7 projects so far, when before I was changing tips every 1 or 2 busy boards.

So, good tinned tip, good full heat, and good contact with the objective pieces.  And I highly recommend getting a dish of tip tinner/cleaner.

Good luck!!

ltt

[vich]

I'm not familiar with a socket.  What is that?

[Dai H.]

IF AT ALL POSSIBLE, get someone who is experienced to show you in person. I bet that would be the easiest way to see what is going on (and you could ask them questions and stuff).

re: the 40W: might be good for some bigger lugs, joints, etc, (probably okay if you are quick) but IMO, a little hot for PCB work.

also:

-maybe you need a little lighter touch
-try pre-tinning the iron just a bit just after you wipe the tip and just prior to making the joint, then using that exact spot on the iron tip to touch and make the joint. Feed your solder to that spot (control feed as necessary), then over to the joint area, then after you about cover the joint, release (the way you release can make a difference--if it's wrong, you'll get a pointy peak or something not shapely).
-solder wick: set wick near the joint, then touch the tip to the joint, see it liquefy, then move the wick in and move the tip to interface the joint and wick, then slide the tip over the wick to encourage the solder to be wicked up, let go. Cut off used portion of wick. Repeat process if necessary 'til all old solder is removed.
-how long should the iron touch a PCB? Maybe 2 and a half or less seconds, but maybe more if it's say a joint in a large ground plane area or something like that (a big lug or whatever--big mass).
-how is the wall voltage? High? This could make things harder by overheating the iron (the solder curdles instead of melding)
-size the solder to the task (example, don't use a huge thick gauge for a tiny PCB joint)
-oxidation, dirt, grime,etc. can hinder the process so wash hands, clean leads, IC, transistor legs, etc. if necessary (I use alcohol). Maybe store parts in plastic if left unused to help retard oxidation.

-and good advice above to practice on some junk to get the hang of it. Until you feel comfortable and confident with it.

[rubberlips]

Firstly,
*Make sure the tip is clean, use a damp (not) wet sponge to wipe off corrosion and excess solder
*tin the tip before you start soldering with a small amount of solder, it will make the solder flow quicker and you don't have to heat as long

If it still doesn't heat too well, maybe the soldering iron isn't one of the better ones. Grab another. I have three soldering irons - two are both 40W and one is completely useless. The other is about 50W which I use sometimes for heavier jobs like backs of pots and automotive wiring.

Pete

[petemoore]

Socket...look around at PICs, and at Runoff Groove, FF articles show sockets pretty good I think...
 Sockets protect Ge's from being overheated, I could use heat sinks to protect the transistor body from dissipating lead heat while being soldered, but I like to swap transistors, and sockets let me just shape the legs a 3 little bit, and stick 'em in/pull 'em out of sockets.
 The better ones I got from Steve at SB, have a line of 'stakes with holes in the heads', these really Grab heavier transistors.
 Otherwise I just use IC Sockets from RS or wherever, the kind with the clamplugs [each lug of this type 'pinches a lead] take the larger diameter leads...I generlly use 3 or 4 pins in a row at least, for physical stability of the socket mounting, also wider stance' for the caps legs.

[petemoore]

If you're using Opamps, IC's...you will need to use a socket...I usually just get get a slough of 8 pin IC sockets, then halve 'em for socketting 2 lug components.
 I learned the hard way about Sockets, building and overheating Smash Drive's LM386's until stumbling onto 'sockets'...someone suggested "Just stick another 386 in the socket and see if that helps' ...lol....Ooohhh Yeahhh,....Tha't HelPs !!!  :roll: