Soldering questions

[Sinphaltimus]

I know low wattage (40 or so) for electronics because that's what I've been told by members here and thats what the internet tells me as well.

 

I have a rather large (8 or so) irons and I have no idea what their wattages are.

 

I think, and correct be if I'm wrong; that wattage ratings are not beastly add important as temperature.

 

I do have a heat reading gun. So, my question is, what is a preferred temperature range for the kind of jobs like assembling boards and modding mainboards?

 

I plan to plug in my irons and get a temperature reading from each one then labelling them so I'll know once and for all what they are good for or not.

 

Your help is always appreciated.

[Omega-TI]

I usually have mine set at 340C which is a little over 640F if I remember correctly.

NOTE: I'm only talking about lead based solder... that new sh__ uh, stuff might have a different temperature requirement.

[Sinphaltimus]

Yeah, I use 60/40 rosin core tin/lead. I didn't even know there was new stuff until about 6 months ago. I've kept a stock.

Edited November 16, 2016 by Sinphaltimus

[Tursi]

The new stuff is a little less pleasant to work with than the leaded. For electronics, you want to keep the temperature of the parts you're soldering as low as possible, heat kills. So just enough above the melting point to be comfortable, and keep time on the pins low. The risk with the heavy duty irons is that they have so much thermal mass they can impart a lot of heat very quickly, whereas the smaller ones take longer.

 

I'm sure there are scientific studies for best practices, but those are the guidelines I learned.

[+InsaneMultitasker]

Using a smaller diameter solder can make a difference. Those large-diameter rolls Radio Shack used to sell are perfect examples of what to avoid (IMHO) unless you really enjoy solder blobs. I have one roll of thin/fine solder for chip stacking and wiring - and a slightly larger diameter for component soldering.

[Sinphaltimus]

I can't even figure out how I screwed up this post. I somehow quoted you saying what I wanted to say.

 

I have several sizes from .022 to .062. Most of my soldering experience has been with heavier gauge electrical as opposed to electronics but I've stocked some thinner solder for the occasional small bits. Recently the need for electronic soldering tips has increased. Youtube is great for that but I prefer to hear it from a group I trust. I just learned about soldering wick. And that's because it came with a soldering station I won on eBay recently. Prior to that I never heard of the stuff. And up until I came to this group (back in August or July), I never used flux.

So yeah, I've been soldering almost since I first owned a TI in 81 but probably doing it all wrong all these years because I never asked or questioned it. And it always seemed to work as expected. Now, I can't afford to be reckless.

Using a smaller diameter solder can make a difference. Those large-diameter rolls Radio Shack used to sell are perfect examples of what to avoid (IMHO) unless you really enjoy solder blobs. I have one roll of thin/fine solder for chip stacking and wiring - and a slightly larger diameter for component soldering.

 

Edited November 16, 2016 by Sinphaltimus

[CC Clarke]

I ran across this thread and thought I'd toss in my .02 since it's a subject I'm familiar with.

 

Choosing a soldering iron is probably the most important issue when building a soldering toolkit. In my soldering career, I've used most just about everything out there, with mixed results. At the low end, are consumer-grade soldering stations that include variable temperature irons with replaceable tips. For most people, this is more than adequate.

 

Apply heat (called dwell time) for too long and you run the chance of lifting pads, damaging the PCB laminate, (small voids, called blisters appear in the substrate, or in extreme cases, the board is charred) or melting the insulation when soldering wires. Too little heat, and you can end up with a non-shiny, cold solder joint, which will plague your work with continuity problems.

 

On the high end of the scale are irons that self-adjust their tip temperature to the application. The first time I used one, I couldn't believe the results. These are hands-down the best thing to improve the soldering world and are the standard in aerospace companies doing high-reliability soldering. There's no guesswork involved. Place the clean tip at the joint, and simply paint the solder, allowing the heat to do the work. Adequate (liquid) flux allows proper solder wetting, giving a smooth, shiny appearance, with no voids, or wavy lines (caused by removing the heat too soon as the solder flows.)

 

The MetCal MX-500 is my goto iron. (The MFR-1110 is fine too.) Info here: http://www.okinternational.com/metcal/english/globalnavigation/products/hand-soldering-systems OK-Industries bought out MetCal awhile back, but retained the name since it's an industry standard. OKI is a good company. I have an old and very reliable OK Industries solder extractor that makes quick work of safely removing ICs from multi-layered boards. I bought it after using a squeeze bulb-type and many yards of Solder Wick to remove solder. The difference was like night and day.

 

For the hard-core hobbyist, or someone who wants a truly great soldering station, I highly recommend buying a (used) MetCal from eBay or amazon, as well as the required tips, which can easily run $25-$40 each. I have about ten different types, from super-small needle points, to curved standard points, and broad points when more heat is required. Note there is only an ON/OFF switch on the MetCals. Everything else is automatic. This is as simple as it gets. Buying used is the way to go.

 

A little info to reduce common confusion regarding solder: I've used them all, lead-free, (big in the EU) No-Clean, and rosin-activated solder.

 

Stay away from lead-free solder if at all possible. The joints look dull and it requires more flux (and subsequent cleaning) to get a good joint filet (slope/angle of the solder flow.)

 

No-Clean solder is more trouble than it's worth. The point is to use it with No-Clean flux which is supposed to reduce clean-up and speed production as well as minimize fumes that can be deposited on optical surfaces. You end up spending more time trying to get a decent-looking joint (which means continued application of heat) and sometimes, it still looks bad. Wetting (solder flow) action is almost non-existent, requiring more solder. This is useful for throughput in wave soldering applications where you're cranking out 1000 boards an hour. For hand-soldering and touch-up work, it's less than fun.

 

Liquid rosin flux is preferred. A great trick a wise man once taught me is to pour a little in a small tin or plastic tray and let it evaporate overnight. (There's alcohol in the flux.) The result is an amber-colored sludge that will harden over time. I put just enough alcohol (IPA) in it just to make it gooey to the point where it sticks to an applicator, then place it on the joint. This is especially useful when lap-splicing two (or more) wires together. The flux stays in place, rather then run down the insulation as with liquid flux. When I'm done, I place the tin into a re-sealable plastic bag until the next time. A tiny bit of liquid flux (a table-spoon) lasts a year, and I solder frequently.

 

There are many different brands of eutectic solder. Kester 44 is preferred, (SN60Pb40) along with their liquid flux. I keep two diameters on hand, .031" and for the fine stuff, .015" Info here: http://www.kester.com/products/product/44-flux-cored-wire You can buy solder and flux from Digi-Key.

 

This is just a quick and dirty overview. The industry standards for solder and flux I cite come from J-STD 001. The 001 standard has a separate addendum for solder and flux, which goes into mind-numbing detail covering each.

 

If you have any questions, please don't hesitate to ask.

 

CC

Edited December 30, 2016 by CC Clarke

[sjt]

You want to use a temperature controlled soldering station.

There are many out there. Some digital some not.

The tips are important too. Some irons like weller wtcp irons, the temperature is controlled by the tip you install.

Tips are sold in different end styles and sizes depending on what you are working on.

Normally 700 deg is a good general one for soldering. Conical shape is common. Obviously a tip to work on a smd device would be

different as compared to a tip to work on a tube radio.

 

Using anything less than the above is best left for wood burning projects.

 

And yes enough heat for the solder to flow smoothly to both metals, and that's all. With experimenter boards it's easy to lift pads.

 

The biggest mistake people make is trying to "paint" solder. The iron tip is at the connection point, then the solder is applied.

 

One more thing, the best way to remove parts and preserve boards is to use a vacuum desoldering station.

A solder "sucker" will work for a lot of things but try removing parts from a board with plated through holes, double sided .

 

Old parts and old boards may benefit from flux as well

 

 

 

Hope this helps

 

Steve