Make a frame from ordinary 2x4s. You be the judge of how big you need it based on the size of canvases you generally work on. I'll describe a frame that will be 24" x 48" on the floor.

You need 2 pieces 48" long (frame rails) and 4 pieces 21" long (cross members).

Before assembly, you'll need to drill the cross members to accept 3/8" to 1/2" wood dowels or metal tubing to be used as canvas supports. The idea is to make a rack that performs the same function as a dish rack where you'd store you dinner plates after washing. The dowels insert vertically into the holes you drill into the cross members on 3" or 4" centres. Don't glue them in because if you use studio canvases that are wider than regular stretched canvases, you'll want to remove every second one.

Buy doweling or pipes to fit vertically into the holes you drill. The diameter of the dowels depends on how thick your canvases are and how much paint you apply to the canvas. If you slather it on really thick, the canvases will be pretty heavy.

Use some scraps to make some blocking for the inside corners of the frame. You can use pieces of 2" x 2" for this. They are cut the same length as the width of the 2x4s. When assembled the 2x4s will be standing on their narrow sides as a rectangular frame. To join the frame members drill pilot holes through the ends of the 2x4s so that when you drive the screws in to assemble the frame you don't split the wood. Two screws into the blocking each way will secure the frame and another couple through the 4' lengths at the corners.

After the frame is assembled press the dowels or pipes into place and you're ready to store your work.

Before you put fresh wet canvases into the rack, test it with dry pieces first to make sure it doesn't tip over. Locate the rack near a wall and lean the work toward the wall, not you or your rack may tip and refinish your floor with wet oil paint.

How big you make your rack depends on how much space you have. The tops of the dowels should be taller than the tops of the canvases or the ends of the dowels will cause bumps in the face of the paintings that take a while to disappear.

Don't overload the rack and don't attempt to take a large wet painting from the middle of the rack without help or you'll have a tragedy on your hands and maybe your clothes.

This rack works well for storing finished, framed stock as well with adjustments made for extra weight and frame thicknesses. Your rack can be small enough to be a counter top model or occupy a large length of wall in an industrial unit.