Arfa Daily said:
No standardisation as far as I'm aware Jim, but it's all much of a muchness.
After a great deal of experimentation with lead frees for repair purposes, I
finally settled on Ersin 309 from Multicore. With the temperature of your
iron jacked up about 15 - 20 degrees C, it behaves reasonably similarly to
leaded solder. Some people I know swear by lead free that's got a touch of
silver in it, but it's quite a bit more expensive, and to date, I haven't
had any problems getting the '309 to 'stick'.
Choosing a solder is, I think, largely a matter of personal preference. The
only recommendations that I've seen is that leaded and non leaded shouldn't
be mixed in the same joint, as it can lead to long term degradation of the
joint's integrity. To that end, it's important to look for the slashed out
Pb symbol or the letters "PbF" on the board, or learn to recognise a
lead-free joint (not hard as they all look like cold bad joints) on boards
that are not marked.
You are right. The whole thing is a bloody mess, as is the entire subject of
recycling and waste management in electronics service. When I have time, I
have a slightly off-topic thread to start on a specific angle of this, that
came to my attention last week ...
Arfa
I don't have your confidence in recognising PbF.
Anyone know their chemistry ?
Test for lead , but would it work with alloyed lead with tin. ?
Yellow precipitate forms with potassium chromate or
potassium iodide. Does tin combine with iodine or
chromium to give a yellow compound?
So far this is my hints/tips for lead free,
but could do with somrthing more definite.
Is that lead-free solder ? some simple, but not definitive
test for lead-free solder.
Lead-free production probably started in Japan in 2001 eg
Japan passed the Electric Appliance Recycling Law, April 2001
eg
http://www.japanfs.org/en/pages/011541.html
"The soldering on every aspect of Sony's DCR-TRV 30 digital camcorder,
released in March 2001, is 99.7% lead-free, including all supplied
accessories. " So probably sets the earliest date.
Genuine , not just assembled, manufactured in USA
is probably lead free solder , up to 2009 anyway.
If a green RoHS sticker on the outside or PbF
marked on the pcb overlay , then lead-free solder.
Some hints for deciding, probabalistically.
If the solder joints have a conical form with sharp
points where component leads emerge then probably lead-free,
compared to a more domed form for leaded.
If more temperature is required to melt the solder
then probably lead-free.
Is the surface appearance of the solder a dusty grey long
before you would otherwise expect it to look old,
asuming its not been stored in a shed or garage.
When you desolder some with a 700 degree F iron, is it "claggy"
ie pastey and lumpy in texture ?
If when molten you push in a stainless sewing needle and extract it
before the solder hardens and leaves a trace on the needle,
leaded will only require a finger nail to remove it
but lead-free will more likely need pliers to remove it
from the needle.