I have been shipping art around the world for the last six years, and in all that time and hundreds of paintings later, I have only had one painting damaged by the post office. I remember reading about professional art shipping boxes way back when, but they were very expensive and I was just starting out in my career and could not have afforded them. I had heard from other artists that somehow the postal workers were capable of puncturing boxes right through. What to do to protect my vulnerable canvases?
 Fortunately, my husband is a man of many talents and he came up with the core idea to prevent poke through from wayward postal people. The rest comes from my own background which includes a course in package design way back in the 70's.
  If you can gift wrap a package, you can create the perfect packaging for a canvas. You'll need a minimum of equipment and almost no money. Let me apologize in advance for choosing a nude to package when taking the photos for this blog entry. I just happened to be shipping it when I finally remembered to take photos while boxing up a painting. Also, it looks like I did the whole thing one handed, but that's only because I was alone and my other hand is holding the camera!
NOTE: If you are concerned about anything coming into contact with the surface of the artwork (and possibly damaging it), please read the note that follows my description of this method.
So let's begin.

Here's what you'll need:
A large sharp utility knife.
Scotch tape
Packing tape. I buy a whole box of rolls at Staples because it's much cheaper to buy it bulk, but you can get this stuff at any dollar store.
Scissors
Plastic bags. These could be from anywhere, depending on the size of your canvas. Garbage bags are good for larger packages.
A sheet of Insulating Foam from any Home renovation center. I use the least expensive they have, one inch thick 2 x 4 foot sheet for about $5. If I am shipping a large piece, I'll use the denser, more rigid version for a few dollars more.
Cardboard Boxes. This is the best part. There is a huge bin for recycling behind every store. And those bins are full of collapsed cardboard boxes of every size. So I go dumpster diving for my cardboard! My favorite stores are Pier I and a home store that carries window blinds. Perfect for big boxes.

Begin by protecting your canvas from the damp. Slip it inside a plastic bag of some kind and fold the bag tightly around it. Tape it closed with Scotch tape on the back.

Next you will be making a foam sandwich. Lay your canvas on a sheet of insulation foam and use the utility knife to cut around the edges forming  perfectly matched piece of foam. Do this twice. You can also use a felt marker and then cut without the canvas on the foam, but I like expediency. The knife will not cut right through the foam, but if you continue your cut in a straight line to the end of the foam, you can simply snap off the piece.

Lay your canvas between your custom made foam pieces to create a sandwich. The foam is rigid and dense enough to protect the vulnerable face of your painting.


Now use your packing tape to bind the sandwich together. Make sure you go the whole way around the package so that the tape can stick to itself in the end. You only need to do this twice to ensure that that foam stays lined up with the canvas.

Next, you will need to lay out your cardboard. If you have an old box, cut along one edge to create a flat sheet of cardboard. Be sure that any printing on the box is facing up. That way the outside of your finished box will be free of printing and ready for a postal sticker.
You'll need a piece that is big enough to wrap all the way around your foam sandwich and leave enough on the ends to fold over. The idea here is wrap the sandwich tightly in cardboard. I lay my canvas along one edge and pick the whole thing up and start bending the cardboard around the foam until I have wrapped the whole thing. I leave an overlap on the final side and cut off any excess.

Here I am using my packing tape to hold the cardboard tightly to the foam sandwich. The same rule applies here, go all the way around so the tape overlaps itself. Tape on tape is very secure and won't lift while in transit. Now you have wrapped your canvas in such a way that it won't be shifting at all within the cardboard.

You still need to finish the wrapping job by scoring the corners with your knife. You want to follow the fold lines created at each corner, to form flaps.

Here you can see that I have folded in the side flaps and I am beginning to fold the last flaps. I make these folds on both ends of the box before continuing.

Now it's time to tape the ends shut. I use tape that goes from one end all the way around the box in one continuous length. I hold the ends tightly closed while I tape and keep tension on the tape.

You can see here that I went around my box on each end making 2 straps that hold down the flaps on the ends of the box. Now I am going around again following the narrow edge of the box. I keep going around this edge continuously until the entire edge is covered in tape. In fact, if you want real security, begin this taping leaving a small overlap that you can fold over to protect the long edges of the box and end with an overlap as well. Tape is very strong when pulled tight and stuck to itself and this method prevents any ripping along the edges of the box while in transit. Yes, it's a lot of tape, but think of it as a security measure.

TaDa! Here is the finished box. The canvas is securely wrapped in both foam and cardboard. The foam will prevent poked holes and the tape will prevent ripping. The canvas cannot move within the box. The long edges are already strong by virtue of the wooden stretcher bars.
  It may take a bit of practice to keep everything tight and get your cardboard cuts right on the first try, but with a bit of perseverance this is easy. If I can do it, anyone can.

A few notes on shipping:
I have an account with Canada Post and so I can print my own labels from my computer. The USPS offers the same convenience. No standing in line, just print your label and tape it on with packing tape. You can drop off the package at any post office or put it in post box if it fits. A word to the wise...NEVER cover the Scan code on the label with tape. The shininess of the tape may prevent the scanner from picking up the code.
About choosing a shipper. I know that many artists feel they must use one of the big shipping companies (FedEx and UPS) for shipping art. In my experience, USPS and Canada Post do a great job of getting your painting where it needs to go. They are much less expensive and there is a lot less hassle and you can still insure your package. You can ship anywhere in the world without worrying.
  I have had to use the big boys on occasion for really large paintings that exceed the max allowable by USPS and not only did it cost me a fortune, but you can be sure that if it's crossing a border with the big companies, it's going to get opened by customs. Take my word for it, customs officers don't give a hoot about your art. Damage will happen, or at the very least you box will arrive mangled. For some reason a box sent through regular mail, even when it crosses a border does not get inspected and ruined.

PS:
I once had a chat with a very friendly UPS guy and he told me that when they package paintings for clients (for which they charge a fortune) they use almost exactly the same method I use. So now you get to be a professional packer. WooHoo!

PLEASE NOTE: I am always shipping oil paintings and this method works perfectly for me. However, I do not build up heavy layers of paint, so my surface is very flat, and I have never had any problem with the plastic touching the surface of my work. If you are concerned with damaging the surface of your artwork, you can protect it by skipping the plastic wrapping and adding a "frame" constructed of insulation foam around the edges of your canvas. If you make the frame deeper than the canvas and hold it in place with tightly wrapped packing tape, it should prevent anything from touching the surface. Then make your sandwich and wrap the whole thing in plastic before adding your cardboard layer.