When you stretch enough good tension by getting some canvas stretching pliers from an art shop. You will also need a powerful staple gun (not a stapler) to fix the canvas to the frame. Start by lining up the canvas and inserting a loose removable staple at each end. Start in the middle of one side and using the pliers gently apply tension and staple. Work your way along the edge. Leave about 4" at each end for the corner fold. Turn the canvas and do the opposite side applying more tension to stretch the canvas tight. Remove the end staples. The ends should be folded prior to stapling. Work your way along the ends as with the sides and fold the corner before inserting the final staples. The hardest bit is getting neat corner. If you google gallery wrap you should find a tutorial on corner folding a decent video of stretching a canvas is here. It's a bit amateur but shows the basic principle. Gallery wraps do sag and wrinkle over time and cannot be restretched easily.
To frame the canvas properly you need bespoke stretcher bars, these are around £20 a set with wedges. The use of these allows you to correct sagging and distortion of the canvas over time. When you use these you will need a frame. You can make one out of plain wood. Fill the joints, sand, paint with acrylics, airbrush or varnish and polish. If you opt to join use good quality wood glue or biscuit joint the corners. Use a plain right angle join as mitred joints are very hard to square and get a good finish. Clamp the frame after glueing to prevent warping and the glue not bonding the frame. leave to cure for 48 hours. Use good quality stopper to fill and sand with medium and then fine paper to produce a smooth finish. If you don't the varnish or paint will show all the tiny flaws and detract from the painting. Create an inner rebate to the depth of the stretcher bars and use swivels to hold the picture in place.
If you are unlucky the print will be chinese and on polyester canvas. This is like stretching a plastic table mat. I would then suggest you PVA glue it to MDF and then try to make a frame. Create a rebate along the inner edge to accommodate the depth of the MDF and drop it in. Screw or staple it to the frame. Over time it will warp and twist and eventually disintegrate. But they are so cheap you can get another one for about a tenner (£2.50 trade).
Ikea, morrisons, wilkinsons, hobbycraft frames are standard sizes. They are not designed to last and cannot be adjusted to suit as the use MDF and composite materials in their construction. MDF also attracts moisture and the dust is hazardous. Composite materials are prone to warping and the frame coming apart at the corners. The chemicals in the glues attacks the canvas and it will spot and deteriorate over time.i use ikea picture frames
I have never really used mountboard on a stretched canvas so I cannot comment on that. I would assume it would stick to the varnish in a similar way to the frame. Although on chinese prints it wouldn't mater much. You would need a glass or plastic cover to prevent the mountboard getting dirty.goto any picture framers and get a decent matching mount
I wish you the very best of luck, it took me 12 months to get stretching right and I am still learning (now in my 8th year). Most of the artwork I frame is 36" x 42" mostly giclée canvasses and originals. Frames vary from 2.5" to 4" in width and 2-3" in height. All I can say is If you value the artwork get it professionally framed. It's a shame your so far away I could have done it for you or let you have a go in my workshop.
