Cheap solder leaving strange residue?

[Jay112]

FWIW, my main roll of solder at the moment is BEST 0.4mm, and it pretty much lives up to it's name of the various Chinese solders I've used over the years, goes on well, good flux content, produces a good looking joint.  No complaints. 

I did once have a roll of "San He" 0.6mm which wasn't half bad either.

I didn't particularly like the Synhonty 0.6 from eBay, and the PPDESD 0.3mm also from eBay was a bit iffy on the flux consistency (probably to be expected at 0.3mm)

But of course, like anything from China, just because I got a good roll of BEST today, doesn't mean that you will tomorrow.

I just realized that the roll I was talking about is of the brand name BEST! I randomly ran into it when I was cleaning.

Mine is .5mm. I'm surprised they even make solders in smaller diameters! Also it says the flux content is 2.25%.

[Jay112]

If someone found an old used unmarked roll of solder, is there any way to determine if it's plumber's vs electrical solder?

[Cubdriver]

Well, for what it's worth, in my experience plumbers wire solder is typically much thicker (like 1/10"ish diameter), and usually solid rather than flux cored, so that's at least something that might help to distinguish the different types.  Plumbers solder also (again in my experience) tended to be 50/50 rather than the 60/40 or 63/37 electronic stuff - the plumbers WANT it to stay in a plastic state longer as it cools so that they can wipe and smooth the joints, as opposed to us electronics types who what it to solidify as quickly as possible to reduce the chances of a cold joint in wiring.

-Pat

[Jay112]

Well, for what it's worth, in my experience plumbers wire solder is typically much thicker (like 1/10"ish diameter), and usually solid rather than flux cored, so that's at least something that might help to distinguish the different types.  Plumbers solder also (again in my experience) tended to be 50/50 rather than the 60/40 or 63/37 electronic stuff - the plumbers WANT it to stay in a plastic state longer as it cools so that they can wipe and smooth the joints, as opposed to us electronics types who what it to solidify as quickly as possible to reduce the chances of a cold joint in wiring.

-Pat

Thanks for responding, Pat! The diameter was thinner than the plumbers solder I'm used to, but thicker than the electrical solder I'm familiar with.

One feature I forgot to mention is that it's in a roll shaped like the one in the following picture, only about twice as long and the roll diameter is about 3 times larger than the following (I have one of the following):

Do you know if plumbers solders ever come in rolls like that?

[Cubdriver]

Hi Jay -

The electrical solder I usually use is 0.031" (0.8mm).  I've also seen (and, in the past, used) thicker electrical solder - about 0.062" dia.  I've never seen plumbing solder in a dispenser pack like you describe, but that doesn't mean it doesn't exist.

Is it solid, or flux cored?  A quick glance at McMaster-Carr shows solid 50/50 solder in 0.062 and 0.125" diameters.  Cored doesn't rule out it being non-electronic - they do make acid core solder, but non cored (solid wire) pretty much rules it out as being an electronic solder (again, in my experience).

Could you post a photo of the solder and package in question?

Do you have a temperature controlled iron?  The 50/50 melts at a temp about 45*F hotter than the 60/40 does (420*F vs 375 for 60/40 and 360 for 63/37).  If you have a temp controlled iron, try setting it for 390-400*F.  If the mystery solder doesn't melt, it's likely 50/50.

If you don't have access to a temp controlled iron, melt a blob of 60/40 and a similarly sized blob of the mystery stuff on something you don't care about scorching (a piece of wood or PC board scrap, for instance).  Heat each in turn to molten (try to heat for about the same amount of time, and note that if the mystery solder takes longer to melt it's likely 50/50), then stir with a piece of wire or the like as they cool and solidify.  The 60/40 should go from liquid to solid relatively quickly, while 50/50 would still seem mushy and moveable for a longer period.

That's about all I can suggest off the top of my head.

-Pat

[Jay112]

Hi Jay -

The electrical solder I usually use is 0.031" (0.8mm).  I've also seen (and, in the past, used) thicker electrical solder - about 0.062" dia.  I've never seen plumbing solder in a dispenser pack like you describe, but that doesn't mean it doesn't exist.

Is it solid, or flux cored?  A quick glance at McMaster-Carr shows solid 50/50 solder in 0.062 and 0.125" diameters.  Cored doesn't rule out it being non-electronic - they do make acid core solder, but non cored (solid wire) pretty much rules it out as being an electronic solder (again, in my experience).

Could you post a photo of the solder and package in question?

Do you have a temperature controlled iron?  The 50/50 melts at a temp about 45*F hotter than the 60/40 does (420*F vs 375 for 60/40 and 360 for 63/37).  If you have a temp controlled iron, try setting it for 390-400*F.  If the mystery solder doesn't melt, it's likely 50/50.

If you don't have access to a temp controlled iron, melt a blob of 60/40 and a similarly sized blob of the mystery stuff on something you don't care about scorching (a piece of wood or PC board scrap, for instance).  Heat each in turn to molten (try to heat for about the same amount of time, and note that if the mystery solder takes longer to melt it's likely 50/50), then stir with a piece of wire or the like as they cool and solidify.  The 60/40 should go from liquid to solid relatively quickly, while 50/50 would still seem mushy and moveable for a longer period.

That's about all I can suggest off the top of my head.

-Pat

Thanks Pat! I think you helped me figure it out! I've never noticed a "flux core" on solders before, but when looking closely at a cross section of this solder it looks like there's a separate core inside! I tried to capture it in the 2nd picture below.

I have a temp-controlled iron, and I could've done that other test you mentioned, but I bet the flux core alone will be a good indicator. I just didn't realize it would be so prominent.

[Jay112]

Ugh, nevermind. I guess I didn't understand that plumbing solder can also have a flux core. I re-read your post and then I realized my error. I got overly excited from noticing a flux core for my first time.

Maybe I'll be able to do that temperature test you had mentioned!

[Cubdriver]

That could be old Rat Shack solder that's long ago lost its label.  They used to sell it in those packages back in the day.  Try melting a bit and sniff to see if the flux smoke has that distinctive rosin scent.  (I'm not sure what the acid core would be like, but probably more of an acrid, unpleasant smell based on the plumbing I've done.)  Obviously, don't take a huge snort of it, just a slight whiff.

-Pat

[Jay112]

That could be old Rat Shack solder that's long ago lost its label.  They used to sell it in those packages back in the day.  Try melting a bit and sniff to see if the flux smoke has that distinctive rosin scent.  (I'm not sure what the acid core would be like, but probably more of an acrid, unpleasant smell based on the plumbing I've done.)  Obviously, don't take a huge snort of it, just a slight whiff.

-Pat

Thanks again, Pat! That's interesting that it looks like an old Rat Shack solder!

I'll do the temperature tests you had mentioned once I become less busy.

Speaking of the Shack... I ordered some cheap stripboards recently from ebay, and on the top of each one was printed the words: "Radio Shaek", like in the following picture:

http://www.ebay.com/itm/322004567483

I wonder why someone would print that at the top of the boards. It seemed strange to me.

[nanofrog]

I wonder why someone would print that at the top of the boards. It seemed strange to me.

Perhaps because they copied their 2760150 protoboard pattern, and is the closest they could get away with regarding the name?  Regarding the RadioShack P/N, it seems the latest version of their website no longer uses the dashes. 

FWIW, there's another photo of one that's been posted on Adafruit with Radio Shaek 1 etched at the bottom (here).

[Cubdriver]

Does this look familiar?




I happened to find it tonight while searching through some old stuff digging for a terminal strip.  I can't imagine that it's from any later than the mid 80s, so it's got to be around 40 years old.  (And no, I don't see me using it any time soon - it looks pretty cruddy!)

-Pat

[Jay112]

Does this look familiar?




I happened to find it tonight while searching through some old stuff digging for a terminal strip.  I can't imagine that it's from any later than the mid 80s, so it's got to be around 40 years old.  (And no, I don't see me using it any time soon - it looks pretty cruddy!)

-Pat

Wow, Pat, the cap looks exactly the same! I bet the chances are pretty low that a plumbing solder would come in the same container with the same cap!