A couple of shipping related things I discovered for shipping FedEx ground

This might be common knowledge, but I discovered a couple of small details this morning that will hopefully help me keep my shipping cost down.

I scrap in small quantities and ship out of state via FedEx Ground 100-200lbs of material at a time. So here's what I found out:

1. Density of material in boxes that I have shipped has been surprisingly consistent at about 0.01 lb/in^3. I got this number by dividing shipping weight of my boxes by their dimensions.
2. Using this density estimate, I got a quote from FedEx that showed that shipping two 60 lb boxes is almost $20 cheaper (for the destination ZIP that I used) than shipping one 120 lb box.

I am curious if having more of smaller boxes is cheaper still. I suspect that it's not if boxes get too small, but I did not go through the exercise to figure out at what point that happens.

I found the best box for me is 24x24x24. I can get right under 60 pounds like that. If I remember correctly I sent out 3 boxes like that. The shipping was alittle over 30 bucks for all

OSHA probably has something to do with that. One man can handle a 60lb box but the shipper has some point where they require 2 men or mechanical assistance. So they factor this into the cost of larger loads.

Good info though.