Pages: [1]   Go Down
Author Topic: The right temperature for lead-free soldering?  (Read 6369 times)
0 Members and 2 Guests are viewing this topic.
Toronto
Offline Offline
Newbie
*
Karma: 1
Posts: 26
Arduino is teh r0xx0r
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

I finally caved and bought a temperature-controlled iron (a Weller WES51: yay, accurate control; boo, arcane °F temperature scale). I don't think I have the right temperatures dialled in yet. What would folks recommend for 96.3% tin, 0.7% copper and 3% silver (MG Chemicals #4900 — http://www.mgchemicals.com/products/4900.html)? At the moment, I'm getting little spherical joints rather than the more familiar conical ones.
Logged

Left Coast, CA (USA)
Offline Offline
Brattain Member
*****
Karma: 361
Posts: 17262
Measurement changes behavior
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Unleaded solder generally does require higher temps. From the datasheet you linked:



Quote
Lead free/leaded solder comparison  Lead Free Solder (Sn/Ag/Cu)              Sn63/Pb37 (Leaded Solder)  
Melting Point                                217-221 º C (422.6 - 429.8 º F)               183 º C (361.4 º F)  
Logged

"The old Europe"
Offline Offline
Edison Member
*
Karma: 1
Posts: 2005
Bootloaders suck!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

If your SAC alloy doesn't 'behave' as expected, there are several things to do:

- make sure your materials are clean in good shape, that is no excessive oxidization is present (dull copper)
- use more flux, maybe even a more aggressive flux
- increase the temperature. once you get 'instant charcoal' it is too high.

You'll have to do some testing. Personally I hate 'lead free' solder, and it hates me as well.
Logged

• Upload doesn't work? Do a loop-back test.
• There's absolutely NO excuse for not having an ISP!
• Your AVR needs a brain surgery? Use the online FUSE calculator.
My projects: RGB LED matrix, RGB LED ring, various ATtiny gadgets...
• Microsoft is not the answer. It is the question, and the answer is NO!

Dallas
Offline Offline
Sr. Member
****
Karma: 3
Posts: 337
nephew as a kittens
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I suggest using eutectic lead/tin solder like God intended.
Logged

"The old Europe"
Offline Offline
Edison Member
*
Karma: 1
Posts: 2005
Bootloaders suck!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

If that is an option, it's the best way to go.  smiley-kitty

I myself tried to go 'green' a while ago and still have a much hated 200g spool of supposedly 'easy to use' and 'quasi eutectic' lead free solder sitting here. Every time I see it, my heart skips a beat or two...  smiley-mad
« Last Edit: January 29, 2011, 01:43:40 pm by madworm » Logged

• Upload doesn't work? Do a loop-back test.
• There's absolutely NO excuse for not having an ISP!
• Your AVR needs a brain surgery? Use the online FUSE calculator.
My projects: RGB LED matrix, RGB LED ring, various ATtiny gadgets...
• Microsoft is not the answer. It is the question, and the answer is NO!

Toronto
Offline Offline
Newbie
*
Karma: 1
Posts: 26
Arduino is teh r0xx0r
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Sorry, leaded isn't an option. I guess I'll just have to fiddle with the temperatures, thanks.
Logged

London
Offline Offline
Sr. Member
****
Karma: 1
Posts: 330
Arduino rocks
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset


As a newbie solderer I found the temp controlled iron was a big help with lead free solder.
I had a big reel of lead solder handed down from my wifes dad. No idea how old it was but its lasted me a long time and gave great results even with a cheap iron.

The difference I found is that the lead solder is more forgiving.
The lead free solder needs extra flux and everything immaculately clean.
I find rubbing the solder pads with the pcb rubbers/cleaners, even if they look clean, essential.

Gordon
Logged

UK
Offline Offline
God Member
*****
Karma: 13
Posts: 903
Twitter: @simonmonk2
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

I have a big reel of leaded solder that I bought in 1980 for what seemed like a huge amount of money at the time. Its getting pretty thin now. But I do find it just so much easier than the lead-free variety.

Given that my last reel of solder has lasted me 30 years, I don't feel too 'un-green'.

You can still buy leaded solder - CPC in the UK sell it, and would hope most of the big components suppliers will sell it too.
Logged

--
My New Arduino Book: http://www.arduinobook.com

0
Offline Offline
Full Member
***
Karma: 0
Posts: 107
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I hate lead-free solder, but I have to use it beacause of work.

I find that for through hole tin/lead i set between 700F to 750F

Tin/lead SMT i set 600F to 650F (a little high)

lead free:
750 SMT
800 TH

now before everyone flips that my temps are high, remember that I solder fast.  These are momentary touches to component leads
Logged

Toronto
Offline Offline
Newbie
*
Karma: 1
Posts: 26
Arduino is teh r0xx0r
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Given that my last reel of solder has lasted me 30 years, I don't feel too 'un-green'.
It's not a "green" thing. It's a "not wanting to have a listed neurotoxin in an uncontrolled cycle" thing. Lead's quite spiffy if you can keep it in a closed use-recycle loop, like with car batteries. The way I solder, the word control doesn't come into it ...

Anyway, with some fiddling about, I've found that 275°C/530°F has a decent balance between
  • melting the solder quickly
  • not burning off the flux before it has a chance to work its magic.

I think I had the iron too hot, hence the blobby, unwetted joints before.

Thanks for all the help.
Logged

0
Offline Offline
Faraday Member
**
Karma: 8
Posts: 2526
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Lead is not the boogey-man some have made it out to be.  Don't ingest it and there are no problems.  This amounts to having the brains to wash your hands before eating and not letting kids gnaw on it.

I find it quite ironic that allegedly "green" groups are pushing CFLs, which contain mercury which is a problem, quite mobile once it gets loose in the environment, etc.

Your 530 degree iron sounds a bit too low to me.  Ironically, a too-low iron temperature can result in heat damage to components.  You can end up with an unacceptably long dwell-time and transfer lots of heat into the part, where a higher temperature will allow you to get the joint soldered and remove the heat source before the component gets so hot.

-j
Logged

Toronto
Offline Offline
Newbie
*
Karma: 1
Posts: 26
Arduino is teh r0xx0r
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Lead is not the boogey-man some have made it out to be.  Don't ingest it and there are no problems.  This amounts to having the brains to wash your hands before eating and not letting kids gnaw on it.

Pretty much all elemental metals are fairly nasty to ingest. Lead's a bad one; there was a lot of lawsuits and industrial action in the early part of the 20th century from the garment makers (white lead used as a marker), painters (white lead causing wrist and leg drop) and petroleum workers (tetra-ethyl lead fumes). Lots of unfun reading in books like Markowitz, Gerald and David Rosner. Deceit and Denial. Berkeley: University of California Press, 2002.

I know I would follow the guidelines, but I can't guarantee that the people that get my stuff after me will. Having known someone whose life was blighted by lead poisoning, I don't want to take that risk.

Quote
I find it quite ironic that allegedly "green" groups are pushing CFLs, which contain mercury which is a problem, quite mobile once it gets loose in the environment, etc.

I work in the power industry. Even if CFLs are disposed in the worst way possible, the mercury released is far less than the mercury emitted by power plants needed to drive incandescents. Either way, I'm glad that domestic LED lighting is now affordable, and I'm replacing CFLs as they fail with LEDs.
Logged

Pages: [1]   Go Up
Jump to: