On my last trip, the airport baggage handlers were less than careful with my case.

I complained and filled out the airline's forms, but the attitude was dimissive.

I decided I was going to have repair it myself.

Step 1: Gather Your Supplies

The aim is to plug the hole but, since it is significant (5mm x 10mm, approximately), the plug will need some support.

You will need:

sugru (obviously)
gloves (optional - see step 3)
some mesh-like support material (I used a piece of an old metal sieve)
scissors, or other suitable tool to cut the support material (not pictured)
a teaspoon (for shaping and pressing)

Step 2: Clean the Hole and Add the Support Panel

I don't have a photo of the raw damage to the case.

The pictures above show the hole after trimming off the loose piece of shell and tidying the edges.

Cut a piece of the support material at least half as much bigger on all sides as the hole.

Centre the support material over the hole on the inside of the case and shape it into the contours using the spoon's handle and bowl. This helps to avoid potential injury from the sharp edges of the mesh.

Step 3: Apply the Sugru Patch to the Inside

I used a single packet of black sugru to blend in with the colour of the case.

If your hole is bigger, you may need more, but bear in mind the bigger the repair, the less stable it may be.

Put on your gloves. Using gloves is optional, but it means:

you won't have to clean sugru off your skin
(it won't do you any harm, it's just more convenient) and
pressing and smoothing the sugru can produce a better finish.

Cut open the packet on three sides and break off about two thirds of the sugru and roll it into a ball.

Flatten the ball into a patch of even thickness that is slightly bigger than the support panel.

Centre the patch over the support material and press firmly into place (picture 1).

It is important that the inside of the patch is forced through the support material to make full contact with the inside face of the case in order to ensure that it bonds well.

Check the outside of the case to see that the sugru has squeezed through the hole slightly (picture 2).

Step 4: Build Up the Patch From the Inside

Add small amounts of sugru to the patch, as necessary, to cover all of the support material.

Press and smooth the patch, tapering it so that things you put in the case won't catch on the edges.

Use the bowl of the spoon to get a clean finish if you're not using gloves.

The picture shows the results that you can get using gloves.

Step 5: Form the Outside of the Repair

Using small balls of sugru, rolled from the remaing third of the packet, build on the sugru that squeezed through the hole from the inner patch.

Press firmly to bond it to the inner material.

Keep adding sugru until its shape roughly matches the outer contour. At this stage, it's better to have a little excess; you'll finesse it later.

Now, alternating between the inside and outside, adjust the shape, checking that neither side of the repair bulges too much.

Step 6: Smoothing and Finishing

The last step is to make the repair look as seamless as possible.

Start by moulding the sugru on the outside to closer match the outer contour of the case.

You may need to remove some excess material. This is most easily achieved by smearing the sugru towards the edge of the repair and wiping it off with your finger. This excess can be reused.

Smooth the surface, tapering it at the edges, as before, to help avoid them catching.

Lastly, check that you're happy with the finish on the inside and adjust both faces, if required.

You're done!