Solder issue.

[sureshot]

Doing a bit of soldering today, usually I use lead free 4% silver 95.5 % tin 0.5 % copper. All's going well. Then to reinforce some traces I used some 60 /40 lead tin solder I had spare, as the high grade silver solder is expensive. Anyway I went back to components soldering, and was getting trouble wetting the joints. I can only assume it was mixing solders, and I might have had traces of the lead tin solder on my iron tip when I went back to the silver solder. Has anyone else ever had problems like this ? Be interested to hear thoughts.

 

[(*steve*)]

I'm not sure specifically about mixing these types of solder, but there are certainly solders that should not be mixed.

It's best to avoid it if possible.

 

[sureshot]

Yes I think your right, I only changed to the high silver content solder as the old 60 / 40 lead tin solder from local suppliers is usless. I was finding it hard to get a good quality lead tin solder so tried this high silver content solder, and got on well with it.

I was only using up a small amount of old 60 / 40 solder for some high current traces, long runs of the silver solder can work out expensive. I must try and find a source of good quality 60 / 40 solder. The silver solder is £15 100g from Maplins, bit expensive, but it works well.

 

[Colin Mitchell]

You have to use eutectic solder.
You will be the first person IN THE WORLD that says silver solder works well.

 

[(*steve*)]

However, silver *IN* solder can be important when soldering components with silver plated connections.

At the bottom of this page are some solder types which include silver. Notably absent is any solder that is predominantly silver.

 

[sureshot]

Yes I get on fine with it, but it is 4% silver content. When the lead free solders became available I did make the mistake of getting the poorer quality solder with no silver in it, I can't remember is exact content % of tin and copper off hand, but its horrible stuff. If you try the 4% silver 95.5 % tin 0.5 % copper solder its really not that bad at all. Yes I did notice the absence of 99.9 % silver solder lol...

http://www.maplin.co.uk/p/lead-free-silver-solder-roll-100g-n32ar

 

[(*steve*)]

Yeah, the page I meant to link to was the wikipedia page on lead free solder.

Solder with a lot of tin in it can have a problem with "tin whiskers". These can lead to shorts developing over time. The inclusion of other metals can help reduce this, and it may be the copper (or even the silver) that is added to prevent or reduce them.

There are a lit of other lead-free solders. All of them have their own advantages and disadvantages.

 

[sureshot]

Something there i've learned.. Tin whiskers, never heard of that, my soldering needs some brushing up on, especially steadiness. Long runs on veroboard is tricky, avoiding solder bridges, i have tried 8 Amps through veroboard tracks alone O-: heated pcb lol.

 

[davenn]

i have tried 8 Amps through veroboard tracks alone O-: heated pcb lol.

yeah not a good idea, you really want to avoid anything of 1A or more through veroboard

 

[sureshot]

Yes, for sure. I reinforce heavy current tracks with solder runs, and links with a heavy gauge copper wire, using two or even three rails for very heavy current loads.

 

[David Moore]

yeah not a good idea, you really want to avoid anything of 1A or more through veroboard

So what _should_ one use for say a 2A circuit that you're making at home?

 

[kellys_eye]

If you make your layout with consideration for the current path you shouldn't be worried about using veroboard for such circuits. If it the works as a prototype you can consider, but are under no obligation, to make a pcb for it using the correct copper design techniques.

I've used veroboard for 40 years and made all sorts of fairly high current circuits using it.

 

[(*steve*)]

You can also parallel strips or physically wire the high current paths.

 

[David Moore]

If you make your layout with consideration for the current path you shouldn't be worried about using veroboard for such circuits. If it the works as a prototype you can consider, but are under no obligation, to make a pcb for it using the correct copper design techniques.

I've used veroboard for 40 years and made all sorts of fairly high current circuits using it.

I'll need to check out what "consideration" means. I don't think I want to get into PCB for some fun home projects.

You can also parallel strips or physically wire the high current paths.

Perhaps this is what consideration means, again, I'll have to check out some resources to figure out what this means in practice.

Thanks for the responses!

 

[kellys_eye]

Yes, 'consideration' as in recognising where the limitations of the veroboard copper strips may lie in respect to the potentially high currents, voltages and, in some circumstances, high frequencies your circuitry may consist of.