Experiences with SN100 Ni+ Solder?

[Rockhorst]

First off: I'm not looking for another debate on ROHS and lead-free vs leaded solders.

On topic: I solder with Stannol HF32 for my own builds but I also do repairs on ROHS pedals. It supposedly is not a good idea to mix. I usually just clear the joint as good as possible and resolder with leaded. When I was researching lead-free solder options a few years ago I stumbled upon SN100C as the best option, but I couldn't find it anywhere for hand soldering use (only bars for solder baths). Yesterday I came across a Dutch website that sells something called SN100 Ni+, which is Tin with traces of Nickel, Germanium and Copper. It seems to be the same stuff as SN100C. It has no-clean-flux at 3.5% which is the same as in the leaded Stannol. Anybody ever used it that could share their experience? Thanks

[somnif]

http://nihonsuperior.co.jp/english/wp-content/themes/nihonsuperior/pdf/pdoduct/download/msds/core/msds_sn100c_030_eng.pdf

Thats the MSDS for SN100C

0.48~0.69% copper, .038~.069% nickle, less than .01% Ge, ~96% Tin, ~3.5% flux

For the record Amazon has wire spools of it (though not exactly cheap).

I can't find any dutch sites listing a "Sn100 +Ni", but I shall keep digging to see if I can compare more accurately.

edit: I am an idiot, I didn't see you link the dutch site. Doh.

[somnif]

Ok, I found a listing of the alloy used in SN100Ni+ and... far as I can tell its the same thing.

Except its not. Felder has a different stock number for them both, and lists SN100C as not containing germanium. But the MSDS I found of the alloy says it does. Maybe its just Felder's version of SN100C that is germ free.

I have no idea anymore. Up is down, black is white, cats living with dogs, all is madness.

[Rockhorst]

Thank for the input Somnif If anything, it made me laugh. Good attempt at figuring it out, maybe I'll shoot them an e-mail for details. More specifically looking for people who've worked with the stuff (either Sn100C or Sn100Ni+) for pedal building (hand soldering, through hole).

[wgc]

Usually the biggest complaints about lead free solder are in hand soldering.  You can deal with other alloys a bit easier in things like wave solder, etc.

You might already know this, but most lead free solders in wire form are something like 97% tin, 2-3% silver, and sometimes less than 1% copper and/or bismuth.

Nickel is a relatively brittle element, so that might be why you won't find it easily in wire form.  The ductility of lead (and low melting point) is what makes it appealing.

It's good practice to not mix leaded solders with lead free (if only to preserve the ROHS) but I wouldn't worry too much about the different lead free varieties, aside from different flux (water sol vs no clean).  In general, not good to mix flux types.

If I remember right, it's better to use no clean for repairs vs water soluble on a repair assy- I think because it can be difficult to remove water soluble flux from no clean residue and you run a much bigger risk of corrosion down the line.  But it's been a long time so I might have that backwards.  Or it might be opinions vary widely too.   

Just wondering at how you arrived at the tin-nickel mix being your best choice? I think the tin/silver is probably fine.

[Rockhorst]

From the comparison charts it seems it has nice properties (close to eutectic, not that high of a melting point, nice shiny joints, good bonding and no tin whiskers and icicles). Of course, this is from a brochure meant to sell the stuff, so I'd like to hear some real world experience.

[wgc]

My earlier post was based on real experience.  I used to support electronics manufacturing in mil spec and then contract mfg environments, including medical devices, during a time when the switch to lead free was just starting to pick up steam (late 90s).  I worked my way up from an assembler to repair tech to process engineer in about 5 years, and then did process engineering and dfm for 5-6 more before I got completely bored and went to grad school.

As you probably know, with any lead free solder (even nickel), the biggest thing is that the joint looks different than it does with tin-lead.  Less shiny, doesn't wet/flow as nicely, needs a little more heat so flux cooks away faster, especially true of no clean.  Operators had to adjust what criteria they were used to using to id a good quality joint.  You never heard such moaning and groaning.    We had to actually do periodic inspections of tool boxes to be sure operators weren't hiding spools of tin-lead.

Also really important to go back to the basics of how to create a nice solder joint, since that becomes even more important when the joint is a little harder to create.  When you do it all day every day, you can pick up little shortcuts that are not great for making reliable solder joints but are good enough to squeak by the QC inspectors.

I personally wouldn't worry too much about tin whiskers unless your builds get hot or have some repetitive mechanical stress.  The copper in the tin-silver alloy I mentioned should help mitigate the risk too.  That said, tin whiskers could be why you are doing repairs...