Stage 6: Final Submission

The final prototype weighed in at 1.012 Kg, a comfy half of the weight limit. It measures 400mm tall, 320mm wide, with a seat diameter of 260mm. The structure is made from 20m of 7mm cotton rope and 750g of epoxy resin, finished with spray paint. 

Stage 6: Painting

Because of the failed epoxy pigments. I chose to finish the stool with a matte finish spray paint. This was to emphasise the texture of the rope and to make it seem like its just floating in place, rather than being soaked in resin.

Two coats of primer.

Two coats of matte white.

Stage 6: Pigmented Epoxy Stool

This is full scale implementation of a pigmented epoxy resin to achieve a white/black finish. When added (at recommended concentration of 2%) the resin turned a milky white, but not quite the solid colour I'd hoped for. The stool was otherwise built with same process  and left on the mould for 24 hours.

Once cured, the colour is a little disappointing. The grey of the rope comes through and looks like a muddy white.

 The biggest problem however, is that the pigment dramatically reduces the rigidity of the composite. The legs flex outward under load and the stool slowly collapses. This unfortunately means instead of pigmenting the epoxy, it will have to be painted instead.

Stage 6: Epoxy Resin Version

The first change in the new model is the mold. It has rotation bearing which makes construction substantially faster. It also has the top removed which allows a impression to be made on the seat. 

This iteration of the design has a few improvements. There is an indent on the seat to improve comfort. The legs have been reinforced along the spine and the stool has better rope distribution overall. The Epoxy casting resin is a little more pliable, and will sag over time but smells better and will take pigments.

An option would be to add a plywood seat for added comfort and strength, but this compromises the cleanliness of the design.

Stage 5: Construction Drawings

Note: after consultation with Daniel, I have decided to just make the rope/resin component and ignore the plywood seat for aesthetic reasons.

Stage 4: 2nd Resin Mockup

 20m 3-core cotton rope, 750ml polyester resin.

First prototype that is successfully weight bearing. Reinforced at crossover points with tiny screws. Had intended to clip the heads off for aesthetics, but this was much harder than anticipated. Legs still flex more than I want, may have to abandon that idea.

Stage 4: Full Scale Resin Test

15m of 7mm cotton rope. 250ml polyester resin. 24h curing time. 

End result looks great aesthetically, particularly the pointed legs. However crossover points had weak adhesion and the legs flexed out under load.

Stage 3: 1:2 Scale No. 2

 82m Kitchen twine on same mould as previous mockup.

Very light, reasonable vertical strength but soft under horizontal compression.

Stage 3: 1:2 Scale Mockup

Standard 250mm tall bucket with spout and handle removed. Covered with grease-proof paper, screws added to wrap rope around.

10m of cotton rope soaked in 1:1 PVA and water mixture. Wrapped around bucket around screws.

Scale model, 48 hours on the mould.

Stage 2: Concepts

Stage 2: Initial Sketches

Stage 1: Research Part B

Material Testing 

Photo Essay

Straight walled drinking glass wrapped in cling wrap then grease-proof paper, to be removed once glue is dry 

Cotton string soaked in PVA glue prior to wrapping

String and twine wrapped around the glass and pen in an even pattern, left to dry.

Grease-proof paper removed once glue has dried. This was far more difficult for the pen, structure was damaged trying to remove it.

Cylinder tested under load. String collapsed under 91g, twine under 74g. Collapse was gradual though.

Beam tested under load. Twine collapsed under 35g, String collapsed under 110g

Larger scale proof of concept. Loose cotton cord, 1:1 PVA to water mix