Finding,buying or making a box can be costly, troublesome and time consuming. I have just taken bumper covers to greyhound wrapped in bubble wrap and taped down tight. I also received a bumper from Greyhound wrapped in a blanket and taped tight, this also worked well.
[This message has been edited by FieroMonkey (edited 04-30-2010).]
"Never shipped the steel bracing before. I would tape the honeycomb to the steel brace (duck tape works best) then wrap that assembly in bubble wrap. Once wrapped put it in the bumper just like it would be in the car. Tape it in (duck tape) then wrap the entire bumper in bubble wrap. Next part is building a box (it sucks) if you start with a appliance box make sure to "keep" 3 sides and just cut down the others to fit the bumper. Also on the cut sides have overlap to give the box structure.
I would also add either some empty boxes or foam blocks to take the weight of the steel beam off the "tips" or rear corners of the bumper if the box is flipped wrong way round. If your just shipping the bumper and honeycomb they are not as necessary since the parts are so light.
As for how to ship I went greyhound express. (just google search for it). You will need to drop it off at your local station and the buyer will have to pick it up at the station on their end.
Their web site has a list of all the station locations. Also the online quote system works well. You just need the total weight and the longest dimension."