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Posted by: Porcharu Feb 5 2008, 11:44 PM

I am building some boards that have to be ROHS approved and I have the approved lead free solder. I am a very experienced (and good) solderer - but this stuff is giving my grief. I have my rig cranked up to max (almost 900 degrees F) and the lousy solder still wont flow nice. It looks like some rank amateur did the work and I am not happy about it.
Any hints on how to use this crap?
Thanks

Posted by: jkeyzer Feb 6 2008, 11:32 AM

The reflow temp is definitely higher, and a good lead-free solder joint looks to me like a bad leaded one. The joints are usually grey and tired looking (not shiny) and the solder doesn't flow as well.

My only experience with lead free solder has been trying to unsolder or resolder bad connections. We keep leaded solder paste in the lab here so I am usually replacing crappy lead free joints with fresh leaded ones... We can get away with it since it's a proto lab.

Posted by: Dr. Roger Feb 6 2008, 01:26 PM

Is there another type of soldier you can try? I remember getting some real lead-free crap one time and never was able to have it work correctly.
it ended up that the flux core solder had no flux in it. Id be curious what would happen if you tried some flux paste on your connectors first... to see if it's the lack of flux or a deficiency in the solder.
That's my $.02. =()

Posted by: championgt1 Feb 6 2008, 10:33 PM

Try to use some flux on the areas to be soldered. Lead free solder should melt well at about 750 degrees. I have heard the stuff sucks, but have not had to use it yet except in a class to learn how to use lead free solder.

Posted by: Porcharu Feb 7 2008, 12:39 AM

Well it was a little better today. New tip on the iron, added flux, hot hot hot iron and it worked so so. I guess the stuff is just nasty to work with. I added flux at every joint and constantly cleaned the tip but the stuff just doesn't flow like real solder. Thanks for the tips, the solder company was no help at all.
I will definitely use proper lead bearing solder when I build my class A amps in a few weeks!

Posted by: banger Feb 7 2008, 01:34 AM

Arent class A amps also known as space heaters?

Posted by: Porcharu Feb 7 2008, 06:31 PM

Yes they are! - I was building a set of OTL tube amps and decided that I could not take the heat load