Intro
Plastic cabinets are great solution for outdoor / balcony storage as they can handle weather conditions, cheaper than any other material and are easy to assemble. Usually are equipped with snap in shelves where those are the parts to fall apart or bent first. In my case, shelves bent too much because of over load but the cabinet itself is in great condition. Therefore, I had two options. Buy a new cabinet having the same results in time or re-make it. So, i have chosen to re-make it.

Step 1: Materials

I have chosen plywood because of its properties as it is strong, lightweight and moisture resistant.

Plywood 6mm for the vertical sheets.

Plywood 12mm for the shelves.

Long piece of wood, strip of 3cm x 3cm (Height depends on shelves number)

wood adhesive.

wood screws M4 x 30mm long.

Long thread screw 4mm (M4)

Hex nylon lock nut 4mm (M4)

Hex nut 4mm (M4)

Washers 8mm diameter x 4mm (M4) => 2

Washers 12mm diameter x 4mm (M4) => 2

Step 2: Tools

Electric drill / screwdriver

A pair of pliers or M4 tool

End Nipper Pliers

Tape ruler

Ruler

Pencil

Step 3: Re-make Measurements

First of, remove all shelves and cut out the bases of them from the cabinet using the end nipper pliers.

The vertical sheets (left – right walls) of the plastic cabinets often tend to bent. To avoid that a good solution is the use of a long thread screw from the left sheet to the right sheet of the cabinet.

By tighten the long screw against the shelves the problem can be solved.

Measure horizontally the cabinet and add an other 2cm to that number.

That will be your cabinet's long threaded screw with enough space for washers and nuts.

With the help of tape ruler measure the distances for the new shelves.

Measure the distances for the vertical sheets. For best durability place the shelves first and then on top place the vertical sheets. If your vertical sheet is say 70cm long and the shelve is 1.2cm thick then the vertical sheet must be cut at => 70 – 1.2 = 68.8cm. Also it's a good idea to cut 1mm more just in case.

Decide how many shelves you need. Shelves need two bases of wood to sit on.

If the shelve is say 30cm in depth, two pieces of 30cm long strip will be needed. If you are going to use 5 shelves a 3 meter strip of wood is needed.

Draw and Calculate everything twice before you regretted!

Purchase all materials.

Step 4: Re-Make It

On vertical sheets draw lines where the wood strips must be placed. Glue and screw all strips.

If the cabinet consists of two or more compartments as mine is, then place the shelves on top of every compartment first. Then on top of every shelve place the vertical sheets. Ones that's done, place the rest of the shelves on top of the wood strips. Have in mind that the shelves sit on top of every compartment might be longer than the others as you are going to use the vertical sheets on top of them. Vertical sheets are 6mm thick.

That's it.

Now, use the electric drill and open all holes for the tension thread screw to pass.

Pass all washers, then tighten up the nuts and you are done.

I can't be more pleased with the end result as the cabinet now is more stable and can handle more weight than ever.

If you ask me if it worth the effort, time and money spent I would say definitely yes!