Overclocking requires overvolting, which increases power dissipation quite a bit. So, overheating which can lead to roasting the ASICs.
As for overclocking what are you doing? Is it a matter of connecting point A to point B on the board? If so is it in tight quarters? I love DIY, but I suck at soldiering small things that are surrounded by lots of other small things! LOL
I'm cooling my 5 blade setup with a box fan, they stay cool to the touch! lol