At 09:41 AM 8/6/2010, Jonathan Hallameyer wrote: > > > > ..or just buy a decent iron like a Metcal that can maintain the temp > > regardless of load. > > >Sounds ideal, but thermal transfer is limited, so all else the same, you c= an >only push so many watts into the joint regardless of soldering iron watta= ge >and regulation. I must respectfully disagree. Its actually very hard for someone who has not used a Metcal=20 soldering station to understand that bumping soldering temperature is=20 NOT necessary when soldering large-mass joints. Really hard. I'll give you an example, though. This was with one of the early=20 Metcal stations - maybe a RFG-30 or PS2E - I don't recall. This blew=20 away the guys in my shop when I showed it to them for the first time. Take an ordinary copper penny (a real penny - one that can be=20 soldered). Place it in the middle of a piece of single-sided or=20 double-sided PCB material that has been cleaned enough to be soldered=20 - perhaps 6" square. Take the smallest Metcal tip that you have. I think that for me, it=20 was either a sttc-138 or a sttc-125. The '125 has a very tiny tip,=20 suitable for SMT work. Add flux all around the penny, touch the soldering tip to the edge of=20 the penny and add a bit of solder to promote thermal=20 conductivity. Wait, then start adding solder so that the entire=20 penny is soldered to the PCB material. Total time - about 1 minute. Observe that the tip temperature does NOT go above the set-point of 700F. Now go and solder a SMT device to a PCB without damaging it. None of the other soldering stations that we have (had) here could=20 solder that penny to the PCB material unless we installed a really=20 big tip - maybe even having to go to an 800F tip in the case of the=20 Weller station. Like I said - its REALLY hard for someone who hasn't used that type=20 of soldering station to understand the difference. dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .