What Type of Solder do I Need when Replacing Capacitors?

[Appleboy45]

I am trying to learn how to solder capacitors. I know what capacitors I need, but what type of solder do I need. I was watching EricTheCarGuy (Not a tech channel, but should show me the basics of soldering, and I am not watching the older video), and he said 60/40 worked better for him then some other type of solder. So what type of solder do I need?

 

Link to EricTheCarGuy video:

 

[Manage My Cables]

6 minutes ago, Appleboy45 said:

I am trying to learn how to solder capacitors. I know what capacitors I need, but what type of solder do I need. I was watching EricTheCarGuy (Not a tech channel, but should show me the basics of soldering, and I am not watching the older video), and he said 60/40 worked better for him then some other type of solder. So what type of solder do I need?

 

Link to EricTheCarGuy video:

 

For any pcb work you want solder with a low melting point ( Higher lead concentration ). You don't want much heat being transferred to the pcb and damaging traces and pathways.

[Appleboy45]

1 minute ago, Manage My Cables said:

For any pcb work you want solder with a low melting point ( Higher lead concentration ). You don't want much heat being transferred to the pcb and damaging traces and pathways.

Ok. I'm not saying your wrong, but does that have to do with the 60/40 rating. Or is what you mentioned different? And what is the lowest melting point you are aware of.

[Huntsman]

Since you posted in mobo sections, I assume you are trying to solder small capacitors and onto a PCB of some sort.

 

60/40 should work fine, the issue is with your soldering iron. Try getting something with high thermal mass to heat concentrated areas quickly so that you can get the job done fast. Else you risk damaging other things like traces and components.

[Appleboy45]

1 minute ago, Huntsman said:

Since you posted in mobo sections, I assume you are trying to solder small capacitors and onto a PCB of some sort.

 

60/40 should work fine, the issue is with your soldering iron. Try getting something with high thermal mass to heat concentrated areas quickly so that you can get the job done fast. Else you risk damaging other things like traces and components.

How do I know if it has a high thermal mass?

[ChrisCross]

32 minutes ago, Appleboy45 said:

I 

if found solder specially made and advertised for microelectronics in my local shop. maybe just walk in there and look. 

[Quaker]

60/40 is just ordinary solder. There is also solder that is something like 63/37 that hardens faster. Either one will work fine.

If you are going to be soldering caps onto a motherboard, or similar, it's best to use fine, flux-core solder designed for electronic work. Also, the best thing to use would be a fine tipped thermally controlled soldering iron, but those can be expensive. Next best is a fine tipped, relatively low power soldering iron (not some big iron used for automotive, etc, use). You don't want excessive heat separating your motherboards layers, or causing other damage.

solder examples - http://www.thesource.ca/en-ca/smart-home-and-household/tools-and-hardware/power-tools/nexxtech-42-5g-%281-50-oz%29-rosin-core-solder/p/6400006

http://www.thesource.ca/en-ca/smart-home-and-household/tools-and-hardware/power-tools/nexxtech-42-5g-1-2mm-hi-tech-solder/p/6400015

iron - http://www.thesource.ca/en-ca/smart-home-and-household/tools-and-hardware/power-tools/nexxtech-60w-soldering-iron-with-variable-wattage/p/6412006

 

Just examples - not necessarily recommendations

 

[ThomasD]

If you are doing repairs you also will want to completely remove the old solder before going with the 60/40.  Solder wick works great for this.

 

The reason being that motherboards are generally made using lead free wave soldering, and because of the higher melting point of thos sort of solder simply applying 60/40 onto it increases the risk of a cold solder joint.  It may work initially, but sooner or later problems will arise.

[mariushm]

If you need to do soldering that has to be super reliable, very professional, etc like doing repairs on airplanes, then yes, you should remove all the solder, clean the surfaces well and use new solder.

In real world, it will make absolutely no difference if you add leaded solder on top of lead free solder or if you replace completely lead free solder and use leaded solder instead. It won't matter.

 

If you're amateur and don't have proper soldering tools (meaning a good soldering station that allows you to adjust tip temperature), you will want to use lead based solder.

 

Lead based solder varieties melt at much lower temperatures (180c .. 183c) which usually means the iron tip has to be at least around 250c to work.

Lead free solder varieties typically melt at around 217c which means the tip has to be at least around 300c to work. 

The temperature must be higher because as soon as you put the iron tip on copper wire or the pcb, the copper pulls heat away from the tip, they act as heatsinks... the tip must be hot enough that even with the action of the metal pulling heat away, its heat must stay above the solder's melting temperature.

A proper soldering station detects this drop in temperature and starts re-heating the tip almost instantly, constantly adjusting the energy going into the tip to keep its temperature at the preset value... a basic soldering iron with no temperature control won't have this kind of feedback, it will just pump energy in the tip at a constant rate.

 

So like I said, lead based solders are much easier to work with, and it's easier to know you did a good job - a proper solder joint will be shiny with leaded solders. Lead free solders don't shine.

60/40 is the most common variety of lead based solders. It's most popular but not the best. The solder melts at 180c and stays for a brief period of time until the temperature drops a few degrees before becoming solid. This flexibility is why it's popular for beginners, you don't need to be quite precise, it's more forgiving but at the same time this phenomenon can cause bad solder joints (if you move the wire while the solder is right at that point of turning from liquid to solid)

63/37 solder is much better, it's an euctetic solder which means the moment the temperature drops below a certain temperature (exactly 183c for 63/37) the solder becomes solid. For this reason, it's much better solder especially if you work in environments with vibrations or movement, like ships for example. You don't have to worry about bad solder joints because the wire shakes exactly when solder turns solid, with 63/37 you lift the iron tip from the joint and in a second the solder snaps solid.

There's also varieties of these two with 1-2% silver or copper. Both are more expensive. The ones with silver are often recommended for surface mounted components with the idea that lots of ceramic capacitors or resistors have the ends silver plated, so the silver in the solder and the silver in the ends combine and results a better joint, but in reality less and less parts use silver these days, so the benefits are no longer there.

The variety with added copper in theory results in longer lasting iron tips and some (very) minimal improvements on solder joints. In real world, again, it probably won't make much of a difference... it's like extending the life of a 9$ iron tip from 6 months if you use it daily for hours at a time, to 7 months. If you use it that often, 9$ isn't that big of a deal and it's not worth spending 2-5$ extra for copper in the solder wire.

 

Lead free is pretty much all the same, crap.. imho not worth buying when lead based solders are still available. You can use lead based solders even with soldering iron tips or stations that say they're designed for "lead free" soldering.

 

Buy solder wire with a good amount of flux (2% or more) and even then, if you can buy a flux pen or liquid flux separately. Apply before desoldering, before soldering, any time you can.

 

Flux is a mild acid that's located in the middle of the solder wire in solid form but turns liquid at lower temperature than the solder itself. As you bring the solder wire close to the tip, the temperature that radiates from the tip makes the flux liquid and activates it (makes it acid) and as it drops on the wires or pcb, the acid attacks and cleans away the thin layer of oxides that's on the surface, and then the actual solder can make the chemical connection between metals.

If you use a cheap soldering iron without temperature adjustment or you have a too hot iron tip, the temperature of the tip can be so high that it evaporates this acid before it actually has time to work on the metals (the pieces you want to join) and adding some liquid flux to the parts before bringing the iron to them can make up for too low amount of flux inside the solder wire.

Since it's a mild acid, it's a good idea to remove

Lead free solders often also have much stronger fluxes, sometimes you have to clean the solder after soldering so that the flux won't continue to attack the copper wire and the pcb, and you need isopropyl alcohol or acetone to remove the flux. Lead based solders don't need fluxes that strong, so you can simply leave the flux on the board if it doesn't bother you (or clean it with isopropyl alcohol, acetone, sometimes even water works).

 

Buy solder with no-clean flux or RMA (rosin mild activated), stay away from highly active or water based fluxes.

 

Don't ever buy solder wires with water soluble fluxes, the name is somewhat of a misnomer, no, you can't really properly clean them just by using a few drops of water. Those solders are best used in factories or manufacturing lines where cleaning of flux can be done properly, These types of fluxes are usually quite acid and will damage in time the pcb. 

 

I prefer Multicore solder but there's other brands that are very good. I suggest buying solder from a brand name, it really makes a difference.

Good sellers of solder and electronic components (authorized distributors ) are Digikey  http://www.digikey.com/product-search/en/soldering-desoldering-rework-products/solder/1310838  or http://www.mouser.com or http://www.newark.com in US  , or http://uk.farnell.com/solder-wire in Europe/Asia or http://www.tme.eu in Europe but you can also buy smaller quantities on Amazon.com  - Farnell and Newark are same company, they just use different sites for different territories.

 

Good brands would be Multicore, Kester Solder, Stannol, Edsyn, MG Chemicals , Alpha Metals. Farnell/Newark has their own brand name "Multicomp", basically like supermarket/mall own's brand, they just rebrand products from other sellers. Some solders under this brand are good quality Multicore or Stannol solders at cheaper price, some solders are from less known manufacturers, so it's hit or miss, if you're lucky you can get great value. 

 

If you never learned about soldering, I strongly suggest watching the first two or three videos from this old series of videos made by Pace (they make soldering stations). It's very dated but the information in the videos is still valid and useful. Here's the playlist:

 

 Lesson 1 is a MUST WATCH , lessons 6 and 7 are also very informative and useful, lessons 2-5 can be skipped because they're about soldering wire to parts which are kind of obsolete these days (no longer used).

 

If you want to see paranoid level soldering, here's a couple of videos about soldering at avionics level, where wires must be cleaned, flux must be used, everything must be very precise and according to some paranoid standards:

 

1. Tinning a wire with solder ( pay attention to cleaning solder, cleaning the iron tip - DO NOT use the sponge, common misconception, cut and throw away a small piece of the solder in case flux inside was melted from previous jobs, don't bring the tip close to insulation)

 

 

REEAAALLY by the book soldering of a radial leaded part according to the NASA standards ... excruciatingly long time to solder a resistor and a lot of cleaning and attention to not touch the parts with fingers so that you won't leave grease on them (contaminate them) .. in real world you really don't have to be this paranoid or measure the ends by the mm or be careful enough to bend the leads at so many degrees or in a particular direction

 

 

And a couple of very good soldering tutorial videos from EEVBlog which contain a lot of tips and examples of soldering, pretty much how those Pace tutorials explain :

 

 

 

Maybe these two should be above, right below the Pace video tutorials but now it's too late, i'm too much of a noob with this forum style, i suck at editing my own posts.

 

Hope this helps

 

later edit : Don't bother with solder wick, because it's basically a strip of copper mesh it's quite expensive for the amount you get, it's often not worth it. Good ones are more than 7-10$ for a meter or so of wick. Cheap ones often don't have flux on them, or very little amount of flux, and flux is what makes the magic in solder wicks. A cheap solder wick will make you swear and throw it away, it would be useless. There's huge differences between cheap solder wicks and $10+ solder wicks.

 

If you do get solder wick, DO NOT drag the solder wick around, solder wick is supposed to be put over the solder you want to remove and by applying the hot iron tip over the wick (a tiny drop of solder on the iron tip will make the heat transfer better) the copper mesh will heat and the flux on the mesh will become liquid and acid and attach the oxides on top of the solder under the mesh, and the solder then becomes liquid and gets pulled onto the wick (physics). If you drag the wick, you can actually damage the pcb.  That's also why wicks without fluxes don't work.. if you buy such crap, apply a lot of liquid flux beforehand on the parts.

 

If you plan on soldering stuff more often than just once, buy a basic solder sucker, it can be just as good as solder wick. put some solder on the iron tip, add it to the place you want to remove solder, press the solder sucker and bring it low enough to touch the solder iron tip then press the sucker again to suck all the solder around the iron tip. It will clean the solder around the tip with no problems at all.