Help with hot air station

[audiofreak19]

So I'm trying to solder a as15-f onto a tcon board. I removed the old chip. Put solder paste across the pins and sat the new ic on top and positioned it. I had my rework station up to 400 degrees F. And air at 15-20. As I wave it around the chip I see the solder paste start to flatten out but it never actually melts into solder and goes on the pins. What am I missing with doing this.

[Th3_uN1Qu3]

Re: Help with hot air station

400 deg F is too low. You want 400 degrees C as read by the station. That, at 1cm away it will be 320C at most, which is perfect.

Think of it this way: Lead solder melts at 183C, but you always have to set the iron to at least 300C to get it to melt, because thermal transfer between the tip and the solder will never be 100%. Same goes for hot air.

[audiofreak19]

Re: Help with hot air station

Yea thanks. The whole Celsius to ferinheight conversion threw me off. I bumped it up to 700-750 ad worked like a charm.

[cdicky]

Re: Help with hot air station

But did your T-con board ever again ??

What make of paste do you use? Do you not like self clean rosin etc?