I decided to go back to my Tetra Brik planter which got mentioned in my last instructable. I left it half finished and developed the 3D printed planter module instead. But seeing as I had this version, that doesn't need a 3D printer, very much resolved too I thought it would be nice to continue it and finish it and share it with you .

I've included a few steps using TINKERCAD to help me calculate the cut off line at the base.

Step 1: Materials and Tools

Materials:

Lots of Tetra Briks (all the same size) here I've used 22

Contact glue

Zip ties

Polyurethane foam

Paint (optional)

Rectangular planter tray (optional)

Soil and Plants :)

Tools:

Marker/Sharpie

small paint brush or piece of card

piece of paper

scissors

Craft knife

TINKERCAD ;)

Step 2: Same Idea Different Results

When I went off on a tangent to make the 3D printed module the idea became a wall hanging planter but the original tetra brik planter rests on the floor.

The overall appearance of your planter wall will depend on the tetra briks you've collected. They all need to be the same size but they may not be the same dimensions as the ones I have used. Unlike the 3D printed version of the planter where the module unit was a cube (all sides equal length) the three sides of my tetra briks are all different lengths so the pattern they create when laid out is not symetrical. So what I did with the pattern was to tilt the briks in such a way so that they are directly above each other. This way the weight ditribution would still be vertical. Thats all very well but it means the briks on the floor will never be in a straight line. We need to cut them to size. So with some drawing skills in TINKERCAD heres a way you can calculate the truncated base. If you would prefer to skip all this technical precision in the following 2 steps be my guest. You could always just start joining the tetra briks together and then just cut them using the edge of a table as a guide for example. Theres more than one way to do anything.

Step 3: Calculate the Trucated Base. Part 1 Brik Layout

I love the word truncated takes me back to technical drawing classes in secondary school. And then there were truncated spurs in geography class. How cool was that? "Out of my way!!! Glacier coming through!"

Anyway, we need to find out the measurements of the tetra briks as they get cut off (.....truncated) so as to be flush with the floor. And remember these tetra briks at the base will be upside down and filled with polyurethane foam so that they won't collapse under the weight.

Start by dragging a box out from the right onto the drawing surface and give it the same dimensions as your tetra briks. Remember when you open up the tetra brik on one end it will be slightly bigger than when its closed. We want the measurements when its open, what its going to be for the planter.

For demonstration purposes lets say its 10 cms. wide, 24 cms. high and 6 cms. deep. But you are going to have to work off the measurements of YOUR tetra briks.

Duplicate the brik just once and move it half the width to the right, the full depth to the back and raise it half of its height. In my case that will be 5cms, 6cms and 12cms respectfully.Then select both bricks and duplicate

Now move these duplicated briks as before but this tme the distance to displace is one full width, double the depth and one full height of the brik (my case: 10 cms,12 cms and 24 cms). You should have 4 bricks lined up in a funny diagonal stepping stairs.

PHEW!.... WELL DONE..... YOUR DOING GREAT! (I'm talking to myself by the way)

Duplicate these 4 briks and move them: one full width to the left, half the depth to the front and lift it half its height. Now you should have 8 briks that interlock nicely in a sort of Minecraft/MC Escher mode. We're just going to have to do one more duplication of all the briks and we'll have enough to calculate the truncated base.

So, go ahead and duplicate and now move the 8 duplicated briks two and a half widths to the right, one and a half depths to the back. It will look like the thirds picture here. Then drop it down by half its height (fourth pic). Last of all move the brik thats the furthest to the left into the gap you see between the third and fourth row: two full widths to the right, one full depth to the back and drop it down one full height. Great! thats the first bit done but change the colors for Part 2 like you see in the last pic.

Step 4: Calculate the Trucated Base. Part 2 Tilting and Truncating

Change the view point to TOP but also make sure you're in orthgraphic mode. Now all of a sudden our briks look flat and square and boring (oh my!). Well, they are just a bunch of cubes after all. But now, in 3 different views or planes if you prefer we are going to turn all the briks together.

Click on the rotating tool and turn all the briks together. By clicking and holding it down drag the curser outside the protactor wheel and you can freely choose the rotating angle. What angle you need will depend on the proportions of your tetra briks but what we want to get is that the corners of the briks of the same color are lined up. Take your time :) when its looking like you've got it where you want it (second pic) switch to LEFT view and do the same.

But this time all the corners will be lining up. Third pic here shows the job already done. I could of lined it up vertically but while I was rotating I brought them all down to being horizontal so that it fits better on a computer screen.

Then change the view back to the TOP and for the final time rotate all the briks so that the corners are aligned. Fourth pic shows the job done. Now we can truncate the bottom briks

Bring out a box hole make it big enough to cover all five briks. Give it plenty of width, depth and height. Line it up with our base briks so they will all be cut in a good position. Too far up and the bottom red briks will get truncated across their top face, too far down and the yellow briks will be cut across their bottom faces. Duplicate the box hole four times and combine each brik with one of the now 5 box holes. And they are truncated! Get rid of all the other briks we don't need them. We still need to measure the lengths of the edges on the truncated bricks.

Unfortunately, we have to go back the way we came. Back through the 3 different views and straighten out the briks again :( Then finally on the works plane we can place the ruler on the points we need and it gives us the measurements. (last pic)

Step 5: Glue the Briks Together

Wow! I'm glad to be finished with those last two steps. That was quite painful. Its a lot easier to work in the real world with the actual tetra briks. Having said that you still need to be careful that you line them up correctly. But don't worry too much, your materials are free so if you go wrong at least you haven't wasted any hard earned cash.

Start lining theTetra Briks up and figuring out where they will be getting glued. Mark out the lines and number them so that you don't get confused. Put the same number on the two faces that will be stuck together and you won't go wrong. Like it often happens with patterns its hard getting started but once you are on the right track its just a question of repeating the steps. I made a simple guide with a piece of paper to mark the areas for gluing. It measures half the height by half the width + half the dept. Fold it to divide the paper into the spaces you need for marking. The only other thing you need to be careful about is the positioning of the cubes at the base and remember they are upside down too.

I use contact glue a lot. I thought it would be perfect here. You apply it to both surfaces for gluing, let it dry 20 minutes or so and then just press them together firmly and they are stuck. You have a lot of control, no slipping and sliding. But you need to be careful when sticking because it can't be unstuck too easily. So make sure you line it up well. You only get one chance. Do them in small batches. Glue the first few together, then go back and figure out the next few you're going to glue, mark them , number them, apply the glue and wait for it to dry again and stick them. And start another batch. When I got to the top I cut two of them down to half the height so that it all finishes in a straight line.

Step 6: Finishing Touches

Spray Paint

I wonder if this was the best thing to do. I hope its not going to be toxic for the plants but I didn't like the look of the print on my tretra briks so I decided it had to go. If I had decided this earlier I could have maybe painted them individually before assembly or maybe wrap them in paper but there would be water damage for sure.

Cable Tie

I cable tied all the places where I glued just in case the glue perishes with time. It was quite tricky to get in and maneuver my hand inside the cartons. I don't have big hands.

Cut The Corners

This is the drainage system the photo shows how I cut through with my craft knife. Self explanatory really, but its nice to see how the bottom point of each brik can drain into the next brik below.

Fill The Base

I was originally thinking of filling the base holes with cement or plaster but then decided on polyurethane foam so as to keep the whole piece lighter. Let it swell up and harden. Then cut it level with an extendible craft knife blade or hack saw blade or something similar.

Step 7: Add the Plants!

I got a suitable sized rectangular tray so as not to make a mess on our balcony. I went to a nice old gardeners shop in town that sell lots of little shutes of herbs and vegetables etc. We dont get direct sunlight on our north facing balcony so the shop recommended the herbs you see in the photo. I just went about filling them up from the bottom to the top just in case it was going to become top heavy too quickly. I also fixed a hook into the wall and tied a piece of cord to it and around the top most center brik. You can hardly see it.

And there you go. I hope you like it and of course you can make this wall planter as large as you like.

Thanks for checkng it out!