For this season we decided to increase and adjust the vegetables gardening strategy as we are running out of space. The idea was to add the production space but at the same time keep the current plant pots.

As some of the plants we have are partial shade we decided to have a raised plant box and relocate these partial shade pots just bellow the main box.

The structure had to be light and resistant, that is why we decided to use steel instead of a merely wooden structure.

Supplies

Material:

1x1 inch 90º steel angle (1/8 thk), 36 feet

3/32 6013 welding rods

1/2" or 5/8" plywood

Wheel Casters

1/4" bolts (screw+nut+pressure washer) 16 sets

Wood glue

Oil based Paint

Marine varnish

Wood sealing media

Brushes, thinner and rags.

Machines:

Welding machine

Angle grinder with a flap disc (60 grit)

Metal cutting circular saw

Drill with 1/8 metal drill bits

Personal protection equipment

Step 1: Design

The design is very easy, it has an overal dimension of:

Lenght: 900 mm

Depth: 500 mm

Height: 800 mm + the casters height

For the box

Lenght: 890 mm

Depth: 490 mm
Height: 250 mm

Step 2: Prepare the Material (steel)

Cut the 1"x1" angle as follows

900 mm (X4)

500 mm (X4)

800 mm (X4)

Step 3: Cut Steel Angle to 45º

Add a 45º cut for all the 900 mm and 500 mm

DO NOT cut the 800 mm segments

Step 4: Arrange and Weld the Base

On a flat metallic surface we arranged the first set. To hold the parts we used 123 blocks on 3 corners and a clamp, a magnetic angle was used to hold the 4th corner.

Before adding the required welding point on the first corner I had to measure the assembly not twice but 4 times. Then I moved to the next corners replacing the plastic clamp and repositioning the 123 block and adding the magnet before adding the next welding point. Of course measuring 4 times before welding.

After the initial welding points were placed I completed the full welding joints.

Measuring 4 times was tedious and very time consuming but totally worthwhile.

Everything was repeated in order to have 2 identical 900x500mm frames.

Step 5: Add the 4 Legs

The legs were easy to weld. You can see them as the green objects on the image. The secret was to use a huge angle ruler.

Again, measuring several times was a key success factor. We used normal pressure pliers (and plastic clamps) to hold the joints.

Step 6: Upper Strip Steel Section

4 3/4" x 1/8 Thk segments were added for the metallic structure top section.

This time it was very fast as the main structure was already welded.

Step 7: Add the Reinforcements

2 3/4"x1/8 Thk steel strips section were added to add rigidity to the general structure and to help to hold the wooden box.

Step 8: Add a Plate for the Wheel Casters

Additional angles were included for two reasons:

1) To support and fix the wheel casters

2) Add structural rigidity on the bottom

They can vary on its dimensions, just make sure there will be space for the 4th required hole for the caster wheels.

Step 9: Drill the Base and Test the Wheel Casters

After removing the welding excess with a flap grinding wheel the caster wheels were positioned to mark the holes and a 1/4 drill was used for the holes.

Step 10: Cut the Wooden Box Material

On the image you can see the box material. There is enough material to build 2 boxes from a single plywood sheet 4X8.

The most important part is the base. Do yourself a favor and test the base on the structure to doble check the propor fit.

Step 11: Assemble the Box (part 1)

Now prepare the wooden box.

On the sides I installed 1x1" wood strips

- Use glue

- Add fasteners

- A counter sink is advisable to have a better final apareance.

Step 12: Assemble the Box (part 2)

Here you can see the box progresion,

Always add glue (Titebond 3 is better as it is a water proof glue)

Step 13: Paint and Seal

Structure:

- Anti rust oli based paint. There are going to be a lot of water once in use, you need to protect the steel.

Box:

- We used marine varnish for the exterior (3 layers) and black dyed resin to seal the box inside. I guess any other water seal media could work as well.