Using different solder types - UK Vintage Radio Repair and Restoration Discussion Forum

Malcolm T · 28th Feb 2024, 10:08 am

Is there any info on the forum about using 60/40 solder with new components pre tinned with lead free solder and the use of re flow flux, has anyone had any experience of this please ?.

cmjones01 · 28th Feb 2024, 11:57 am

Don't worry about it. I've been mixing 60/40 tin/lead and lead free (mostly SAC305 alloy) solders in my lab since the whole RoHS thing in 2006 and never had any problems. If a joint fails, it's always because I've not soldered it properly, not because of any weird metallurgical issues.

I'm doing prototyping, development and repairs, not volume production, but for hobby use I'd say there's absolutely nothing to worry about.

Chris

kalee20 · 28th Feb 2024, 12:14 pm

There's no problem. Use 60/40 as you always would.

(It's the other way round that there's a problem - using lead-free on leads coated with 60/40. You need no lead, or quite a bit - there's a no-mans-land concentration range, of just a very few percent lead, which leads to a brittle joint).

Malcolm T · 28th Feb 2024, 1:55 pm

Many thanks for the feedback .
I will continue with the 60/40 !

emeritus · 28th Feb 2024, 5:30 pm

I was taught on a workshop course many years ago that tin progressively diffuses from solder to copper, and vice versa. The reduced tin content and increased copper content of old solder, raises its melting point, which is why very old solder can be difficult to melt unless assisted by a dab of fresh tin/lead solder to dilute it and lower its melting point. I believe that tin/lead solder is still required for certain applications where high reliability is essential.

kalee20 · 28th Feb 2024, 7:57 pm

Tin/lead is certainly required for hi-rel applications, the company I work for uses it in the majority of cases.

In the fullness of time, it may be that unleaded solder is accepted in this industry too. Right now, lead-free has no long-life pedigree, and both tin whiskers and tin pest are known problems with lead-free solder (and are inhibited by the presence of lead). And the niche industries, being relatively small volume and which don't end up in landfill generally, don't negate the general aim which is to keep lead out of the immediate environment.

28th Feb 2024, 10:08 am	#1
Malcolm T Hexode Join Date: Dec 2018 Location: Lugo, Spain Posts: 483	Using different solder types Is there any info on the forum about using 60/40 solder with new components pre tinned with lead free solder and the use of re flow flux, has anyone had any experience of this please ?.

28th Feb 2024, 11:57 am	#2
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,677	Re: Using different solder types Don't worry about it. I've been mixing 60/40 tin/lead and lead free (mostly SAC305 alloy) solders in my lab since the whole RoHS thing in 2006 and never had any problems. If a joint fails, it's always because I've not soldered it properly, not because of any weird metallurgical issues. I'm doing prototyping, development and repairs, not volume production, but for hobby use I'd say there's absolutely nothing to worry about. Chris __________________ What's going on in the workshop? http://martin-jones.com/

28th Feb 2024, 12:14 pm	#3
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,081	Re: Using different solder types There's no problem. Use 60/40 as you always would. (It's the other way round that there's a problem - using lead-free on leads coated with 60/40. You need no lead, or quite a bit - there's a no-mans-land concentration range, of just a very few percent lead, which leads to a brittle joint).

28th Feb 2024, 1:55 pm	#4
Malcolm T Hexode Join Date: Dec 2018 Location: Lugo, Spain Posts: 483	Re: Using different solder types Many thanks for the feedback . I will continue with the 60/40 !

28th Feb 2024, 5:30 pm	#5
emeritus Dekatron Join Date: Jan 2012 Location: Brentwood, Essex, UK. Posts: 5,339	Re: Using different solder types I was taught on a workshop course many years ago that tin progressively diffuses from solder to copper, and vice versa. The reduced tin content and increased copper content of old solder, raises its melting point, which is why very old solder can be difficult to melt unless assisted by a dab of fresh tin/lead solder to dilute it and lower its melting point. I believe that tin/lead solder is still required for certain applications where high reliability is essential.

28th Feb 2024, 7:57 pm	#6
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,081	Re: Using different solder types Tin/lead is certainly required for hi-rel applications, the company I work for uses it in the majority of cases. In the fullness of time, it may be that unleaded solder is accepted in this industry too. Right now, lead-free has no long-life pedigree, and both tin whiskers and tin pest are known problems with lead-free solder (and are inhibited by the presence of lead). And the niche industries, being relatively small volume and which don't end up in landfill generally, don't negate the general aim which is to keep lead out of the immediate environment.