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Lead-free solder: looks like cold solder joints?

Started by Bucksears, April 30, 2012, 09:21:35 PM

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Bucksears

April 30, 2012, 09:21:35 PM
I just switched to a new roll of lead-free solder (never used this stuff before) and everything I've used it on so far looks dull/silver. It changes right before my eyes after I take the solder iron away. I've tried touching it a 2nd time with the iron tip, but it does the same thing.

I tried a little bit of other solder I had lying around and it looks shiny/chrome when finished.

Is this typical of lead-free stuff, or did I get a bad roll of solder?

R.G.

#1
April 30, 2012, 10:03:10 PM
"Lead free solder" is not one thing. There are many alloys of lead free. Many of them go dull upon solidifying. Depending on the alloy you have, it may be working as designed.

Let me be very clear here: lead free solder is a disaster for the DIYer. If your government has not prevented you from using 60-40 or 63-37 rosin-core tin/lead, use it. Even if you have environmental scruples, you are not making a billion cell phones which will go into landfills, which was the argument for enforcing elimination of leaded solders.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

Cliff Schecht

#2
May 01, 2012, 01:15:40 PM
While I'm not disagreeing that leaded solders are better for home use, the technology has come a long way and the problems that we used to have with lead-free solders (cat whiskers, cold joints and such) have for the most part been worked out. I've worked in a few RoHS compliant labs and never really had a problem using the RoHS solder as long as there is a good quality iron at the bench.

amptramp

#3
May 01, 2012, 02:28:01 PM
Quote from: R.G. on April 30, 2012, 10:03:10 PM
"Lead free solder" is not one thing. There are many alloys of lead free. Many of them go dull upon solidifying. Depending on the alloy you have, it may be working as designed.

Let me be very clear here: lead free solder is a disaster for the DIYer. If your government has not prevented you from using 60-40 or 63-37 rosin-core tin/lead, use it. Even if you have environmental scruples, you are not making a billion cell phones which will go into landfills, which was the argument for enforcing elimination of leaded solders.

If the government was serious, they would address the thousands of tons of ammunition hunters use that all finds its way into the ecosystem without the barriers present in a landfill site.  +1 on using 63-37 where you can.

Ice-9

#4
May 01, 2012, 03:59:27 PM
One thing that irritates me about lead free solder is that when doing repair work to circuit boards even some good irons are just not hot enough to make an easy job of melting the solder. I usually have to feed in some lower melting point leaded solder before desoldering.
www.stanleyfx.co.uk

Sanity: doing the same thing over and over again and expecting the same result. Mick Taylor

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Earthscum

#5
May 01, 2012, 04:02:09 PM
They're a bit more serious than you think. One or two bullets stray from a rifle, which is miniscule compared to the amount of lead scatter in wetlands from shotguns. They have laws on it now. I actually have a 16G that I have to have modified from a full choke so I can shoot steel on public lands. You get caught with lead scatter near a public wetland and you could get a hefty fine.
Give a man Fuzz, and he'll jam for a day... teach a man how to make a Fuzz and he'll never jam again!

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frank_p

#6
May 01, 2012, 04:06:42 PM
Quote from: Cliff Schecht on May 01, 2012, 01:15:40 PM
While I'm not disagreeing that leaded solders are better for home use, the technology has come a long way and the problems that we used to have with lead-free solders (cat whiskers, cold joints and such) have for the most part been worked out. I've worked in a few RoHS compliant labs and never really had a problem using the RoHS solder as long as there is a good quality iron at the bench.

What are they ? What solder station they use with it ?  I would really like to try that.  Thing is I don't even like normal flux fumes...  So...   :icon_neutral:

Earthscum

#7
May 01, 2012, 04:20:00 PM
I've been using the silver bearing solder from RatShack with a 25 35W iron. My only complaint is that I run through about 6 tips per roll of solder... But I have read that it is common among the RS irons. Other than that, my joints come out nice and flow really well.
I touch the pad then dip the solder in and roll the tip into the lead. As soon as it flows to the lead it is secure. The pad is where you want your heat concentrated since it is a larger area, and it keeps excess from the lead before you get the solder to flow. For a visual example you could youtube how to braze or weld steel. They should have great examples of differential heat sinking, and easier to see than how to solder vids.
Give a man Fuzz, and he'll jam for a day... teach a man how to make a Fuzz and he'll never jam again!

http://www.facebook.com/Earthscum

R.G.

#8
May 01, 2012, 05:07:36 PM
You're right Cliff. Many of the problems have been worked out. However, even today's best lead free solders require more skill and attention to detail than 60-40 or 63-37. I've used several of the solders; the Sn-Cu variety is a disaster. The Sn-Cu-Ag is much better. There are other alloys with bismuth, antimony, etc. to get to lead free. I have not sampled them all. None of them area as easy to use as tin-lead. But they can be used if you strive for process consistency.

But for beginners, why complicate it for yourself?
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

trixdropd

#9
May 01, 2012, 05:21:39 PM
+1 on the radio shack silver bearing solder.  I use an auyou station and set the temp at 420c. I have no issues other than not as shiny joints.

Cliff Schecht

#10
May 01, 2012, 05:54:26 PM
Quote from: R.G. on May 01, 2012, 05:07:36 PM
You're right Cliff. Many of the problems have been worked out. However, even today's best lead free solders require more skill and attention to detail than 60-40 or 63-37. I've used several of the solders; the Sn-Cu variety is a disaster. The Sn-Cu-Ag is much better. There are other alloys with bismuth, antimony, etc. to get to lead free. I have not sampled them all. None of them area as easy to use as tin-lead. But they can be used if you strive for process consistency.

But for beginners, why complicate it for yourself?

Agreed. I only use RoHS stuff when I'm told to do so, otherwise it's 63/37 for everything.

I thought almost all of the new non-RoHS solders have antimony and bismuth added to them. It's been a while since I cared enough to even look but one of these two additives is what helped cure the whiskering problem.

As far as irons go, most real labs that I've been in use either Metcal irons pretty much throughout or higher end Hakko or Weller stations (usually Hakko over Weller IME but both are good brands). I had a WD100 station at my house for years on loan and it did fine with most anything I threw at it.

DiscoVlad

#12
May 01, 2012, 06:27:44 PM
As far as lead free solders go, this seems ok to use, though it's pretty expensive. (Sn-Cu-Ag)
http://newzealand.rs-online.com/web/p/solders/6258132/

This however: http://jaycar.co.nz/productView.asp?ID=NS3094 is complete garbage. (Sn-Cu), or it could just be that using brands other than multicore is a bad idea. ;)

Neither of them are as easy to handle as Savbit (Sn-Pb-Cu) though, which is what I use most of the time unless I have to use lead free.
http://newzealand.rs-online.com/web/p/solders/0554951/

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