Originally Posted by
SteveH
With all due respect that has not been my experience.
Bubble wrap is "ablative" in that once popped it is no longer padding. EVERY box that I have received with bubble wrap has has a significant portion "popped". IF the seller uses other padding between the bubble wrap and the box it is MUCH less likely to be damaged.
The issue comes from the padding acting as a weight support structure. So a 40 lb sewing machine sitting on two layers of bubble wrap gets dropped on the ground twice and the inertia of the machine coming to ANY sudden stop, tends to pop the bubbles even if the box is UNDAMAGED on the outside... After the first drop the padding can be reduced increasing the chance of the second drop damaging the machine.
My Jones Serpentine has a broken paw foot even though the box was only compressed 1/2" on that corner... because it had two layers of bubble wrap and both layers were popped.
Double boxing is ALWAYS preferred if possible.
I wrap a cocoon of bubble wrap around the machine, and then fill in around that to secure it inside the box.
Now I don't ship heavy cast iron machines, so if I did, I might alter my methods. Plus, cast iron can be brittle, so extra care would obviously be needed to protect it.