When it comes to heavy copper PCB, there are many benefits. Copper that is heavy duty and used in PCBs means that thermal strain will be reduced. Not only that, but there will be improved current conductivity. Both of those things are important because these days thermal management is crucial due to higher currents. Another benefit is that the copper increases connector site strength, and it can survive thermal cycling.
Those are only a few benefits. Bear in mind that the copper is available in various weight, such as 20 ounces, 10, 4, 3, 2 and one ounce. It’s a good idea to determine approximately how much of it you’ll need before ordering it. As for where to get it from, there are many places you can order it online, as well as select stores, but ordering it online is the best way to get it.