Why the shipping cost so high for a powder container?

Recently we got many enquiry from customers who want to buy powder containers from us, like kinds of powder hopper, but when we quote the shipping cost to them, hardly never got the reply. but only one client replied and asked me why is so expensive?

Because the shipping service like DHL/ TNT/ FEDEX/UPS always calculate the cost based on the volume weight, that is to say length by width by hight (cm) then dividedby 5000 comes the volume weight.

For example: the size of carton for hopper COLO-62  :  64x38x38cm.  its volume wieght is 18.5 KGS, although its only 8 KGS. In order to save the shipping cost some times we will suggest client to buy some other small spare parts like pump, spray gun to filled in the hopper.