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I understand from first hand experience that Lead Free solder is more difficult to use than leaded solder. But for a PCB, if I were to use Lead Free solder paste, are there any serious drawbacks using that instead of Lead solder paste? For my application, this is for hobby PCB application. I don't have a curing oven, so I planned on using my hot air station to melt the solder paste. Thanks.

Jay
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  • I have not had problems. I'm not sure how it'll work with hot air, though: I made myself a reflow skillet with an electric skillet from Goodwill (US$5), a thermocouple meter from eBay (US$25), and a sheet of tempered glass for a lid, which I scrounged. Temperature control is manual, and the heat-up cycle is probably on the long side of correct, but it only takes 15-30 minutes to reflow a board and now that I'm actually holding temperature on the preheat step (which I wasn't before, on the excuse that the skillet gets up to preheat temperature slowly) it's working quite well. – TimWescott Oct 19 '19 at 21:56
  • and many other duplicates – search for "lead-free solder paste" on this site. There's a wealth of hard info and experiences out there. – Marcus Müller Oct 19 '19 at 22:16
  • The main drawback would be the higher melting temp. With your hot air method this might be a significant issue. https://www.kester.com/Portals/0/Documents/Knowledge%2520Base/Alloy%2520Temperature%2520Chart.pdf&ved=2ahUKEwjai9-GsanlAhVVIDQIHSEiDyIQFjAAegQIAhAB&usg=AOvVaw2__AhNEk0LAlTIImfZdTH9 – Ben Watson Oct 19 '19 at 22:39
  • There are lead free alternatives that have pretty low melting points. One of the prototyping companies I use uses one that is at about 230°C. It is both annoying and handy. I tend to solder of components that I want to keep especially when I use my own solder for which I need to heat more than that. It is handy as it is not very hard to solder off a component compared to other prototypes. – le_top Oct 20 '19 at 00:29
  • @le_top Yes but a 37/63 lead solder paste has a melting point of 183 C which certainly has the potential to make things much easier. (I see that my previous link is not working, but it had a table of solder types and melting points) – Ben Watson Oct 20 '19 at 01:06
  • If you have no experience in these issues , you will fail until you get experience on profiling to optimize yield and oxidation , PCB layout to solder bridge, excess/insufficcient solder issues. I was Eng Mgr for CMAC with a few SMT lines so I can tell you , its easy, but there is a learning curve cost. GO watch youtubers. When lead-free first came out I was Operations Mgr for an RF R&D AMR wires company. We did all 24hr turn around on RF protos with hot air and hand solder Std lead solder . We wanted reliability for prototypes then switch to lead free for production. That worked. – Tony Stewart EE75 Oct 20 '19 at 03:31
  • I also wore hats for IT, CE, component QA , test engineer, stock rom database and BOM mgr for 10k diff parts in stock. etc. Did cost reductions etc. Learn lead free if yoiu have time otherwise focus on whats important. – Tony Stewart EE75 Oct 20 '19 at 03:36
  • @BenWatson I am interested in that link ;-) . 183°C is lower than 230°C, but generally solder melts closer to 300°C, so 230°C is already pretty low. – le_top Oct 20 '19 at 12:50
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    @le_top https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.kester.com/Portals/0/Documents/Knowledge%2520Base/Alloy%2520Temperature%2520Chart.pdf&ved=2ahUKEwi9u9ulrazlAhWlHzQIHZayAVEQFjAAegQIBBAB&usg=AOvVaw2__AhNEk0LAlTIImfZdTH9&cshid=1571626652700 – Ben Watson Oct 21 '19 at 02:57
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    @BenWatson Thanks - here is a direct link: https://www.kester.com/Portals/0/Documents/Knowledge%20Base/Alloy%20Temperature%20Chart.pdf . Looking at this chart 230°C is a pretty high temperature... I'll use it in the near future to select some other lead-free solder wire ;-). – le_top Oct 22 '19 at 10:02

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