There are different types of solder for various soldering jobs but what is the best solder for electronics? Many people assume that all solder is for soldering in the electronics environment but that is not the case. There are other types and uses for soldering and using the wrong type of solder for electronic construction can cause all sorts of problems.So what is the best solder for electronics?
Soldering is used to join copper together. The component legs and tracks on a printed circuit board are copper. Another trade that joins copper together is plumbing where they solder the pipes and fittings together. You definitely don’t want to be using plumbing solder for electronic construction as it contains an acid which won’t do electronic components much good.
I also used to have a solder for joining aluminium and copper. It looked like normal solder but was thicker and greyer. It melted at a similar temperature as I used to be able to melt it with an ordinary 25 watt soldering iron, but it made a bit if a hissing and spitting sound which I think was down to the flux contained in it. It wasn’t particularly good at joining aluminium and I suspect that it also contained some sort of acid like plumbing solder so again its best avoided for soldering electronics.
For many years the solder used for electronics was all pretty similar, it contained tin and lead. I think it was actually 63% tin and 37% lead. This has the lowest melting temperature of all solders. There was also 60/40 which has a slightly higher melting temperature. It was available in various thicknesses and in various size reels. As you probably know you need flux to solder with and conveniently the supplied solder had a core of rosin based substance so it was added to the solder as you actually soldered. This had all remained pretty much unchanged for years however there is now a different type of solder.
A few years ago new regulations were introduced to Europe in which certain substances were banned from the manufacturing process and without wishing to bore you even more, lead was one on them. The regulations were the restrictions of hazardous substances which was abbreviated to RoSH. This is the term you might see associated with the new types of solder.
Lead free solder melts at a higher temperature than the old lead 60/40 stuff so as a result it isn’t as easy to work with and using it will obviously require more heat which is the enemy of electronic components and circuit boards. Lead free solder is also more expensive than the traditional lead solder. Two big points against lead free solder!
So for me the winner is traditional lead solder. It's cheaper and easier to solder with and less chance of causing heat damage to components and circuit boards, also it’s been around for years and years. I personally have built projects that are at least 35 years old with 35 year old soldered joints made with lead solder. These projects are still functioning perfectly and the joints all still look fine. I have no proof that the new lead free solder won’t stand the test of time but then I have no proof that it will. It has also been noted that using lead free solder shortens the life of soldering iron tips.
As time goes on I guess lead solder will get hard to find and so the price will increase. I also wouldn’t be surprised to find a tax or levy stuck on it either. Lead free solder is also in its infancy and I expect as with anything it will probably get improved on in the future. Hopefully the price will drop and they will find a way of lowering the melting point a bit as well but until that happens I’m sticking with lead solder.