is the temp going to be a problem
eg when desoldering with wick will i need the higher temps
thanks for the help angel
Well, that's the thing. The short answer is: no, you do not need a higher temperature. However, that is only one part of the issue.
Solder melts at a specific temperature. It doesn't care if it is on a tiny solder pad, a huge copper plane, or whatever. The problem is the thermal recovery of the soldering tool. The classic construction is a heater plus a sensor combination, into (or onto) which you put the actual tip. The first problem with this is that the sensor does not measure the tip temp but the heater temp. The next problem is that you have a rather large thermal mass between heater and tip. Plus, you have a thermal resistance between the tip and the heater, since they are two separate units.
Now imagine you put the tip onto a heavy copper plane or something else that conducts heat quite well. The tip itself will cool down because the heat is transfered away. However, it takes some while (due to the thermal mass) until the "other end" of the tip also cools down. It takes even more time until the actual heater cools down and the sensor notices it. By the time the sensor registers the change, the tip itself has cooled below the melting point of the solder.
In a system like the JBC or the Metcal units, the heater and tip is basically one single, small unit. They keep the tip temperature much more constant under heavy thermal load changes. Sure, you can crank up the temperature, but then you "overheat" the solder joint at the first contact, and also once the stuff you solder has heated up. Not to mention that you have to dial down the temp again if your next solder joints are small. In the end you are constantly fiddling around with the temp setting, or risk overheating the parts.
So, yes, you can use a classic construction as well by simply turning up the heat, but it has its drawbacks. It is much preferred to have the actual tip temperature kept constant even when the thermal load has big changes, which is what the JBC would do much better.
Greetings,
Chris