This is another project made of cardboard.
The art of recycling objects must be used, not simply in school projects, but in our homes! At least for economy!
This armchair was made of cardboard large boxes, 12 years ago.(In this case, an fridge box). It was only an test, and I didn't finished the project as it should be. I stored it in the attic. After I posted the Doll's Sofa project, I remembered it...
I photographed the model, but as I wanted to post it right today, (I want so much to win the Laser Cutting Machine - I have various ideas of what to do with it), I solved to draw the project to make a better image of it. Notice that the fabric wasn't appropriately put in it, it was just put to suggest as should it be. (Trully, it's only a big table towel on it). I thank my daughter-in-law and my son that posed sitting on it to show it's resistance and to my younger son that translated this text and make you suffer minus, as you would with my English (Yet, I might have made some mistakes, sorry then...)

Step 1: Materials and Measures - Arms

Materials:
PVA glue, adhesive tape, cardboars & cardboard pieces or Resistant fabric (cotton or nylon material).
Fabric and floam (or cotton) for the seat, back and the armchair arms.
Resistant cardboard box or double cardboard plates.
Arms Materials:
Obs:- the detach numbers correspond to the vein size.
2 cardboard plates of 60 cm X 125 cm (55 + 15 + 55 cm) [A]
If you dont have the big dimensions cardboard plates, you can use cutted plates with 55 X 60 cm (4X) [A1] e 15 X 60 cm (2X) [A2]
And 4 more plates of 55 cm - (x) X 15 cm - 2(x) for the sides [B]
Where x is the cardboard thickness.

Step 2: Front Part Material

Front part of the armchair seat materials:
One 55 cm plate (At least) X 85 cm or 2 of 55 X 35 cm & 1 of 55 X 15 cm'.
and 2 more plates of 35 cm - (x) X 15 cm - 2(x) to the sides.
The measure referred as 'At least' might be increased until 180 cm to craft an Sofa!

Step 3: Back Piece Material

Armchair Back Materials:
2 plates with 100 cm X 40 cm to be cut with the following measures:
Lower plate has 40 cm. In one of the sides, with 90º corner 100 cm and above in 90º corner 20 cm. In the lower parts of the 90º corner 35 cm, & parallel to the lower part, 10 cm. From the Final Point of the 10 cm until the Superior part,(20 cm) draw a line that will form the back (around 70 cm)
Verify the draw to understand it better.
A piece with 235 cm X 55 cm (or 1 piece of 100 cm X 55 cm + 1 piece of 20 cm X 55 cm , 1 piece of 70 cm X 55 cm , 1 piece of 10 cm X 55 cm and finally 1 piece of 35 cm X 55 cm)
The assembly most important part is to understand that there is necessity of reinforcing the structure by the inside after the pieces assembly. The most reinforced, most weight it will support.

Step 4: Assembly - Part 1

Pieces Assembly:
Arms/ lower front & back ' back parts:
Bend the piece [A] (if the plates are cut less) in the lines (35, 15, 35 cm) marking with a pen or some non-cutting object for the bend happens in the right place. If the plates are cut, join them with adhesive tape the 3 parts. Put 2 pieces (1 in each side) of the lateral piece [B] and put the adhesive tape. You can use a bit of hot glue on the contrary of the adhesive tape and then complete it with glue. Don't be afraid of overstate the PVA glue.
By the inside, use the glue to fix all of the parts and put the cardboard plates or fabric above the glue to reinforce. Observe by the pictures that were made reinforcements with the cardboard in the laterals (You can use the lateral sizes as base), but the best to do is to put more internal reinforcements. You can so do use cardboards canes like the ones I used in the Table\Bench project. The PVA glue takes long to dry, but in this case, it is the best thing to be used because of it's efficiency.
Do the same with the other pieces (See the drawings) and wait the glue completely dry.

Step 5: Assembly - Part 2

Armchair Assembly:
Join the pieces as the images and photos shows using glue and wait it until it get dry. Use heavy objects to press the pieces in places or use adhesive tapes or tie a wire around the assembled armchair.

Step 6: Assembly - Finish

From that moment, you must decide if you want to use the internal space as a chest to store things or not. If you will use it as chest, then the seat must be made of wood and will be used as a cover. otherwise, use cardboard rests with 35 cm of width to reinforce the seat in 'zigzag' as the image shows; Then cover it with a cardboard plate. Verify your seat's measures, because this measure might vary according to the manner that the pieces where united.

Done! Now, the armchair structure is ready and can already be used!

Sorry about the mess my attic room...

Step 7: Cover the Armchair

In the following instructions, I will only suggest a manner to cover the armchair with foam or cotton and fabric.

Here some tips to cover the armchair.
Cover the armchair will give a structure more strong, then, I think that is a great idea!
The amount of fabric depends the piece size .To measure the front down (front base) to back down plus 30 a 40 cm to permit a adequate finish. Verify how large is the piece and calculate the double to cover the arms too.
First, put a foam or cotton around the upside arms as show the figure. Then, cover with fabric and fix under (inside part) with PVA glue. Stretch and fix to the other side, under the seat. Do that in the other side. In the front and back of arms, fix with glue.

Step 8: Cover the Armchair (cont.)

To the middle part, use a measure of fabric with 30 cm more that the middle size to package the foam or cotton sides. Put glue all cardboard of the central piece (you can fix the seat part first, then the other and another -it is more easy) and finish the central cover in the inside parts (front and back).
To front side, front and back laterals and laterals of central piece, use a cardboard mold these pieces with less 1 cm in each side . Cover as show the figures and fix in the indicate parts (see figures).
You can finish with cord around the cover pieces after fixed with glue.
To finish the upside down , cover with cardboard, fabric or EVA.
Good job!