Solder types? - Page 1
Forum section: electronics / beginners

author: jimjam
author_rank: Regular Contributor
timestamp: May 25, 2014, 03:35:49 am
content: My goodness, all my life I've only known about 60/40 lead solder vs 70/30 (which I don't use). Now I came to this forum and started reading about lead free vs lead solder, and then I read about 63/37 ratio, etc.So without getting into too much technical / scientific detail... which one should I use?

author: zapta
author_rank: Super Contributor
timestamp: May 25, 2014, 03:51:36 am
content: Dave discusses it here around the 10 minutes mark

author: TVman
author_rank: Frequent Contributor
timestamp: May 25, 2014, 04:03:13 am
content: 60/40 Lead Solder is the one I have(with Flux)......

author: echen1024
author_rank: Super Contributor
timestamp: May 25, 2014, 05:59:12 am
content: 60/40: Long considered industry standard. Has a ~10* range of "plasticity" where it is both solid and liquid63/37: Eutectic. It has a definite melting point of 183C, which means that it has no plastic range and is either solid or liquidI prefer 63/37, as there is no time needed for cooldown, especially with SMD, but the choice is ultimately up to you. I would ust go for the more modern 63/337.

author: mariush
author_rank: Super Contributor
timestamp: May 25, 2014, 09:39:23 am
content: You have A LOT of information here about solder, you just have to be curious enough to search for it and read:http://en.wikipedia.org/wiki/SolderLike echen, I prefer 63/37 (0.56mm wire) simply because the solder hardens right away (it's eutectic), as you remove the heat and temperature goes down to 183c. But I sometimes also use 60/40 taking advantage of the fact that it stays plastic for long time, for example when I try to desolder some stuff (add solder to all pins, keep solder liquid, pull out part)You may want to watch a few of the videos here as well:https://www.youtube.com/playlist?list=PL926EC0F1F93C1837Part 1 discusses solder and flux:

author: jimjam
author_rank: Regular Contributor
timestamp: May 25, 2014, 11:10:08 am
content: WOW Amazing information! I always do a great solder job but never knew what was really happening. I just know what a good solder job looks like and how to achieve it. Now I understand it better! Thank you so much.Now a new question arose. Is Flux considered dangerous goods (flammable), i.e. one that cannot "fly" with you on an aeroplane?

author: mariush
author_rank: Super Contributor
timestamp: May 25, 2014, 02:14:54 pm
content: Fluxes are acids ... light ones, that are activated when heated most of the times, they're harmless at room temperature. So I would say you're fine with carrying them on planes.Stuff that may raise eyebrows would be some thermal compounds/pastes... some have Beryllium oxide which is toxic and cause cancers and a specific disease...see wikipedia page for it. You also wouldn't be allowed with Gallium, which weakens some metals:

author: Nerull
author_rank: Frequent Contributor
timestamp: May 25, 2014, 03:13:34 pm
content: Check the MSDS on your flux. Many use flammable liquids as solvents, often alcohol. Those are considered hazmat and special shipping regulations apply. That doesn't mean they can't be shipped air, but there are rules to follow.

author: John Coloccia
author_rank: Super Contributor
timestamp: May 26, 2014, 02:39:33 am
content: Quote from: jimjam on May 25, 2014, 03:35:49 amYou should use 63/37 if you can. It has every advantage over 60/40 for hand soldering. You can't even buy Kester 48 in any lead mix other than 63/37. 60/40 is anachronistic.

author: jimjam
author_rank: Regular Contributor
timestamp: June 23, 2014, 09:18:50 am
content: Revisiting this topic again. I ended up buying a roll of 60/40 solder roll. However I got some lead-free tube to try out, and it doesn't seem all that different compared to lead solder. I probably need to work more with it to know the real difference.

author: GreyWoolfe
author_rank: Unknown
timestamp: June 23, 2014, 12:54:14 pm
content: If you are going to play with lead and lead-free, make sure you have separate tips for each. Mixing lead and lead-free solder will give poor solder joints. IIRC, lead free requires more heat and is more corrosive to tips, shortening the life of the tip. As always, if I have provided wrong info, someone please correct me.

author: jimjam
author_rank: Regular Contributor
timestamp: June 23, 2014, 01:04:47 pm
content: Quote from: GreyWoolfe on June 23, 2014, 12:54:14 pmThankfully my soldering iron came with two tips!But ideally I'd like to just stick with one type of solder. I guess I'll work with both for a bit and make up my mind.

author: exxon
author_rank: Newbie
timestamp: June 23, 2014, 02:14:12 pm
content: Nobody here seems to care about RoHS Directive.Lead alloys are forbidden in EU and a lot of other places.It is around 10 years now we are using Sn-Cu alloy only.

author: Monkeh
author_rank: Super Contributor
timestamp: June 23, 2014, 02:15:50 pm
content: Quote from: exxon on June 23, 2014, 02:14:12 pmBecause it doesn't apply to us.QuoteRestricted, and no, there are many alloys in use, including lead ones.

author: exxon
author_rank: Newbie
timestamp: June 23, 2014, 02:30:31 pm
content: We discussed a lot this matter inside our company.Today you find only RoHS compliant components, they have pure Sn or Sn-Cu finishing on their pins. Soldering them using Sn-Pb alloys can drive to poor reliability because of the weak interface between low-temp melting alloy and hi-temp melting pin plating.Using a hi-temp Sn-Cu alloy assures a perfect joint that Sn-Pb can't attain.

author: nixfu
author_rank: Unknown
timestamp: June 23, 2014, 02:39:33 pm
content: 63/37 .... There is NO alternative.Seriously....beginners. Get 63/37, you will have more consistent joints because there is little chance of you moving it while its cooling and causing a bad joint.I consider 60/40 to be for more advanced and specialized uses, and really recommend beginners get 63/37. 63/37 is also the best go-to solder for the bench in most cases.Once you use it, you wont go back to 60/40 without a reason.

author: peter.mitchell
author_rank: Super Contributor
timestamp: June 23, 2014, 02:50:20 pm
content: Quote from: exxon on June 23, 2014, 02:30:31 pmPb free for production, but for the lab, Pb stick things together easier and isn't sold to customers.

author: exxon
author_rank: Newbie
timestamp: June 23, 2014, 03:20:25 pm
content: Quote from: peter.mitchell on June 23, 2014, 02:50:20 pmAt the beginning of the "leadless nightmare" we followed this way. We were happy to have an easier life in the lab than in production line.Then this double-life caused more troubles than benefits (reworking i.e.). Now we become accustomed in soldering with Sn-Cu in the lab too, and we do not regret the past at all.

author: zapta
author_rank: Super Contributor
timestamp: June 23, 2014, 05:02:00 pm
content: Quote from: nixfu on June 23, 2014, 02:39:33 pmI followed Dave's advise in one of the videos and got 60/40. Does 60/40 has any advantage over 63/37?Also, my solder paste is 63/37 and I am doing reworking with 60/40. Any problem with this mixing?

author: zapta
author_rank: Super Contributor
timestamp: June 23, 2014, 05:05:22 pm
content: Quote from: exxon on June 23, 2014, 03:20:25 pmYour company switched to Sn-Cu only when your government forced you. It didn't do it when it had a choice.Some of us are still free to choose. ;-)

author: Monkeh
author_rank: Super Contributor
timestamp: June 23, 2014, 05:13:52 pm
content: Quote from: exxon on June 23, 2014, 03:20:25 pmIf you were having soldering issues in the lab, you have bigger problems than using leaded solder with lead-free components.

author: free_electron
author_rank: Super Contributor
timestamp: June 23, 2014, 05:30:21 pm
content: Quote from: exxon on June 23, 2014, 02:14:12 pmnonsense. there are many categories of equipment that are not subject to ROHS or WEEE. prototypes and hobby are not subject.If you really want to go lead-free in a lab environment get SN99c or SN100c. Stay far away from that SAC305 junk.

author: theatrus
author_rank: Frequent Contributor
timestamp: June 23, 2014, 05:45:46 pm
content: I've had good success with Kester K100LD. It's far better than SAC305 for wire solder.

author: jimjam
author_rank: Regular Contributor
timestamp: June 23, 2014, 07:19:42 pm
content: Translation please, what are those SN99c, SN100c, SAC305 and K100LD?

author: nanofrog
author_rank: Super Contributor
timestamp: June 23, 2014, 10:40:15 pm
content: Quote from: jimjam on June 23, 2014, 07:19:42 pmDifferent lead free alloys.SAC alloys are named for the first letter of each element in the alloy, and the numbers represent the silver and copper content. SAC305 would be Sn 96.5, Ag 3.0, Cu 0.5 for example (there are a couple of others, SAC387 and SAC405). It's the most common because it's cheap (certainly not the best performing). SN100C and K100LD are more recent, and the marketing literature insinuates performance is similar to 63/37 (i.e. good wetting, nice and shiny joints, low erosion, and cost effective).This linkmight help, as it gives a brief description of what some of the different alloys are used for in the Comments column (.pdf).

author: mariush
author_rank: Super Contributor
timestamp: June 23, 2014, 11:18:49 pm
content: If the above link isn't good enough, this should also help:http://en.wikipedia.org/wiki/Solder#Solder_alloysYou can choose between two kinds of solders : eutectic solders or not eutectic solders. 60/37 is just one alloy that's eutectic, it becomes solid or liquid at exactly 183c.Eutectic solders transition from liquid to solid in a very small range of temperatures, some under 1 degree Celsius. The other types of solder have a certain region in which they're plastic, they're between solid and liquid. For example the classic 60/40 has a region between 183 and 188-190 degrees Celsius.Eutectic solders are better for situations where there's vibrations or you want to control very well how fast the connection hardens and joint is made.Non-Eutectic solders are good for situations where you want to take advantage of that plastic region of the solder, for example if you'd want to desolder a connector or something else you may want to add some of that solder and heat up every solder point and extract the part as the solder on each connection point is still in the semi-liquid state.Then there's solders that contain Lead and solders that don't contain lead. Solders without lead usually melt at higher temperatures, usually 217 degrees Celsius or more, so it's more difficult to solder because your iron has to be hotter which in turn can shorten the life of the iron tip (hotter iron tip means more oxidation, means less iron tip life).Also, it's more difficult to desolder or solder componetns on commercial products such as motherboards because these products typically have a lot of copper in the pcb layers which sucks all the heat from your iron tip, thus you iron can't reach that 217c+ temperature easily.If you solder at home, hobby stuff, there's no reason not to use leaded solder, unless a particular component is tinned with a material that would react negatively with your solder (it's very rare).With lead free solder, it's often best to use solder that works best with particular components, for example some surface mount components are tinned with silver, so it would be a plus to use solder that has a tiny bit of silver in it.Other people use solder that has a bit of copper (Cu) in it, because this type of solder is easy on the iron tip, it lasts longer in theory. But an iron tip is generally cheap and lasts a long time, so you shouldn't select a solder wire just on this reason alone.One reason lots of people are afraid of leaded solder is all the misconception about lead being toxic and so on. The reality is lead used in the solder doesn't get heated up to such degree by the solder iron that it would turn into vapors or particules going into your body, so you won't "absorb" lead by soldering using leaded solder. The only way you would get lead from soldering with leaded solder would be from rubbing the solder wire in your hands for hours and even then, it would be a minuscule amount of lead particles - you probably breathe more lead daily than what you'd absorb that way.In fact, it's actually worse for you to solder using lead free solder.All solder wires have flux built in - flux is a sort of acid that is solid inside the wire (in a somewhat neutral state) but turns to liquid (and acid) when it warms up from the iron tip and pours over the surface you want to solder, attacking the oxides and preparing everything for the actual solder. This way, a good connection is made.In a lead based solder, flux typically melts at around 160-180c and has a bit of time to "attack" the surface before it evaporates from the heat of your iron tip.As lead free solder turns liquid at higher temperatures, people need to use irons at higher temperatures and manufacturers also have to use more powerful/corrosive fluxes that would attack the surface much faster because the flux will be burnt or will evaporate much faster due to the higher iron tip temperatures.The smoke from all fluxes is bad for your lungs but lead free fluxes are generally much worse than the mild fluxes used in leaded solders.So if you're not educated, you may think you don't get lead poison by using lead free solder, but you're actually hurting yourself more if you breathe in that smoke coming from the lead free solder.//ps There is some debate if it's a good idea to combine leaded solder with lead free solder... for example if the pads or holes on a pcb are tinned with lead free solder, some say you should not use leaded solder on the pcb, because the joints will be weakened. I don't think it's such a big deal in the "grand scheme of things" but you may want to do more research about it.Beginners that read this thread may want to learn a lot about soldering from this old series made by Pace - even though the videos seem a bit outdated, the information inside is still valid:

author: jay
author_rank: Regular Contributor
timestamp: June 24, 2014, 10:47:03 am
content: This discussion thread is going to cost me some moneyI've been using 60/40 and now decided to get other types.. A local shop where I'm about to get other things does not have 63/37 but they have Sn62 Pb36 Ag2 and Sn62 Pb37 Cu1. After studying wikipedia and couple of other sources I'm almost sure that those are also eutectic and similar in use. Will I get the 63/37 magic experience also with 62/36/Ag2?

author: nanofrog
author_rank: Super Contributor
timestamp: June 24, 2014, 12:20:17 pm
content: Quote from: jay on June 24, 2014, 10:47:03 amYes.It's eutectic like 63/37, and has a slightly lower melting point (179C instead of 183C). Meant to be used on parts/components that are silver or silver plated to prevent leaching, but won't hurt anything that's not (just more expensive due to the silver content).