Shipping 80lb amps.

I will also add one suggestion as a shipper.  Skip insurance.  If you ever have to make a claim, you'll be making $2/hour for all the time you spend on it, not to mention frustration.

Instead box it so they CAN'T break it.

Jerry

There are at least three different entities involved here and you need to understand the rules of all of them! Basically, it's your amp UNTIL the customer gets it and is happy. Yes, happy. It can arrive at their door in perfect condition and if they choose to refuse it, the return charges are on you. If it's damaged and the buyer refuses it, you could get it back and be compensated .19 cents per pound! (This happened to me). If you're using Paypal, they almost always side with the buyer in a dispute. Understanding ALL the rules will save you some grieve. Like many said above, over pack it. Good luck. Joe

I don't know if it's been mentioned already above, but there's a good chance you'll get hit with US Customs duties, unless you pre-arranged that with the shipper. 

Yeah the correct answer is box it well. The original box was only designed to be shipped on a pallette with the other 50 boxes stacked next to it. Also shippers use less care these days. Just a sign of the times we live in. They wear headphones and are just not plugged into the job they're doing.

Don't: double box it with peanuts. Peanuts migrate.

Do: take a roll of HD bubble wrap and wrap it several times around the original box in 2 directions. Then find a 'heavy' box (strong cardboard) that it will fit in. Use foam/bubble wrap pieces to fill any gaps. There will be at least a 4-6" gap from the original box from the outer box. Then write fragile all over it with a thick red marker.

You will not need insurance with this type of packing. But never a bad Idea.