Help with choosing good solder - Page 1
Forum section: electronics / projects

author: Kakashi
author_rank: Contributor
timestamp: March 01, 2020, 10:06:20 am
content: I know about Kester/Multicore and such... But these are the solder brands that I can order locally. I can order from eBay or Amazon but due to the high shipping costs, I want to see if some solder is usable from my local shops.The solder will be used mainly for soldering SMD components but also for through-hole, more rarely though.Also, I've seen solders with added copper or silver, but never used them before. Should I consider them?(they are not listed here due to their a bit higher price. If they are worth it, I can buy one)HQ 250gr - SN60PB40-0,70-250GFelder 500gr - SN60PB40-0,70-500GFixpoint 250gr - Sn60/Pb38/Cu2 0.56mmSTANNOL 500gr - Sn60/Pb40 1mmAlpha 500gr - Sn60/Pb40 1mmCynel 1kg - SN60PB40-0,70-1KGPlease help me choose which one is the best from the list, without regard to the price or weight.

author: jonpaul
author_rank: Super Contributor
timestamp: March 01, 2020, 11:16:24 am
content: Hello impossible to assist until you say your country or location and intended use of the solder.SMD rework? Building TH DIY? Repair of an appliance?All solder you mentioned are non ROHS, low quality, 60/40 is a poor choice, with cold joint possible due to the wide plastic temperature range.The best non ROHS is 63/37 eutetic. The copper or other metals increase the melting point.The diameter...too small or too large is wasteful and also leads to poor soldering.Suggest to Read the information on the large solder manufacturers web, AIM, Kester and alpha.Good luckJean-Paul

author: MarkF
author_rank: Super Contributor
timestamp: March 01, 2020, 01:01:24 pm
content: https://www.eevblog.com/forum/beginners/the-best-solder-for-electronics/msg2527947/#msg2527947I useKester 63/37 solder 0.031" diameterfor general purposes.The 63/37 ratio is much easier to work with than the 60/40.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: March 01, 2020, 04:48:47 pm
content: If you can't get anything else, the world has survived quite well with plain old 60/40 and good technique. Get an RMA flux core. Get some extra liquid rosin flux, which will solve many problems.

author: tooki
author_rank: Super Contributor
timestamp: March 01, 2020, 06:22:33 pm
content: Quote from: Kakashi on March 01, 2020, 10:06:20 amBearing in mind that this question gets asked every few weeks, and the answers don't change, I'd go for Stannol, Alpha, or Felder from that list. But if you're doing SMD, then 1mm is WAY too thick, and 0.7-0.8 is right at the upper limits in my experience. 0.4-0.6mm is better for most SMD soldering IMHO. For SMD, silver-bearing solder is actually a good idea (even if not strictly a must), since many SMD components like ceramic caps have silver-plated terminals, and solder with silver in it is gentler on those terminals. With that said, I don't normally bother with that myself. Some people say it's harder to work with than pure tin-lead, which remains the gold standard (especially 63/37, which is the absolutely ideal solder).Have you considered just ordering some leaded 63/37 Kester or Loctite/Multicore/Henkel from Digi-Key? They'll ship it around the world, and in most countries the shipping is free above $50, which is easy to accomplish with a $35 roll of solder and a few random components. (You can never have enough banana plugs and stuff!)

author: magic
author_rank: Super Contributor
timestamp: March 01, 2020, 06:37:18 pm
content: I have some Sn60Pb38Cu2 and I see no difference between that and standard Sn60Pb40. Lead-free is PITA, much harder to wet poor quality surfaces.0.7mm is IMO a decent compromise between SMD and THT, but if your primary use is very small SMD then 0.5mm may be more convenient. Thin is still usable for THT, you just feed more of it. But price is usually higher.If you are in the EU, buy some more because it's banned and may disappear from your shop in near future

author: Ian.M
author_rank: Super Contributor
timestamp: March 01, 2020, 07:26:01 pm
content: Sn60/Pb38/Cu2 and other high Cu alloys have the major advantage that they don't dissolve significant quantities of copper. This makes them significantly better for soldering very fine wires, and also extends the life of soldering bits that don't have thick iron plating protecting their copper core.There's no way to pick the 'best' from the list without knowing what you are going to be using it for and what type of flux core they have.Some fluxes (core or separately applied) are absolutely unsuitable for hand assembly, rework and repair unless you have a heated ultrasonic cleaning tank + the manufacturer's recommended cleaning solution to remove their residue. Some are allegedly 'no-clean' but that only applies if *ALL* the flux reaches the activation temperature up around the solder melting point - not a problem for flux in a core but if you are hand-soldering, how sure are you that extra flux didn't get under a nearby part without reaching its activation temperature? If not, you can have a major corrosion problem within weeks or months. Also many no-clean fluxes residues are much harder to remove (compared to ordinary rosin fluxes) if, for any reason, you *have* to clean them.Excessively thin solder is a PITA for through hole work and larger terminals. You can take three strands of thin solder and twist them up together, but that gets real old real fast if you have a lot of joints to do. If you are doing both through hole and SMD work I'd recommend getting both 1mm or 1.2mm and 0.56mm or even smaller.If you are repairing modern electronics assembled with ROHS Pb-free solder, you should have compatible solder for the repair work as wicking off all the Pb-free solder so you can re-make the joint with Sn/Pb thermally stresses the pads, increasing the risk of board damage, and mixing Pb-free and Sn/Pb alloys vastly increases the risk of dry joints.(N.B. Sn60/Pb40 tolerates small additions of Pb-free solder as up to 8% just moves it closer to the Sn63/Pb37 eutectic.)I'd recommend an Ag containing Pb-free solder for general ROHS repair work. If transitioning from SnPb to Pb-free without changing bits, wipe and re-tin your bit three times to reduce Pb contamination to below the ROHS limit.

author: Someone
author_rank: Super Contributor
timestamp: March 01, 2020, 09:02:58 pm
content: Quote from: Ian.M on March 01, 2020, 07:26:01 pmCompletely agree. The flux type/quantity can have a much larger effect on the result than the alloy, even comparing lead free.