Wet Sock
Release status: concept
[[image:|center|190px]]
| Description | A paste or slurry extruder with a knitted wrap
|
| License | |
| Author | |
| Contributors | |
| Based-on | |
| Categories | |
| CAD Models | |
| External Link |
Contents
Introduction
Imagine 3D printing a house.
Well the concept has been demonstrated but not having heard big news it obviously means that there are still some kinks to iron out.
I have an idea that may make it practical a lot sooner, perhaps not the way it will be done always but something that might be put into practice with just a bit of putting together of parts.
Implementation
Think of combining three concepts. First a continuous tube knitting (or woven if it can be made easily) machine that can make an endless stocking. Then think of a regular sausage making machine that extrudes the mince into a tubular casing. Lastly consider that some things built with sandbags have a long life. These days houses can be built with them, they have been used in fortifications, flood and erosion embankments, and consolidation of all sorts of other earth works. When filled with a cementitious mixture (wet or dry) on wet curing stacked bags are almost as strong as a single casting.
Now the full picture, a tube knitting machine surrounding a nozzle say 5cm (2 inches) in diameter that either has a slurry or paste extruded or a dry mix blown into it like stuffing is inserted into a teddy bear. The slurry could be plain sand or earth or a weak mix of sand and Portland cement. If the mix is dry then it would make sense to wet the casing and the receiving surface as it is extruded
Benefits
- Easy to test with discreet lengths of sock knitted on the side
- Can build faster than any other system that needs to gain setting strength before next layer
- Can be designed to add tensile strength with choice of fibres
- Wet or dry application possible
- Can be used with low cement mixes
- Can be used with most pasty materials that will ooze through the sock a bit
- Sock can be made from cheap organic fibre or long life geo-textile fibre for exposed surfaces
- Can jump over gaps by pausing extrusion with empty sock
- Can bridge over gaps by maintaining sock tension (catenary span)
- A double skin wall can have staples easily inserted between skins
- Sock diameter could be potentially adjusted on the fly
Drawbacks
- A second consumable needs to be supplied
- Full strength only after setting period
- Extrusion head has added complexity
- Bridging would be best done with a prop placed across the gap on the layer below
Challenges
- Investigate suitable knits
- Investigate suitable mixes
- Compare pumped slurry and blown dust transport
- Test out the new LRC licensing model, this idea is free for private use, available for commercial licensing
- Try and find out if prior art exists
Relevant Forum Threads
Other links
- The Sandbag House High quality sand bag framed house building, too good for low cost housing market
- Natural Building Course is run to train people to build with sandbag houses
- ecoBUILD technologies Promoters of sandbag houses, even multi storey
- STUDY ON VEGETABLE WASTES AS REINFORCEMENT has research on the comparison of various plant fibres in extruded concrete reinforcing
- THE ROLE OF POLYMER ADDITIVES Discusses the use of additives in the extrusion of cement composites
- [ISBN 978-1889625058] Emergency Sandbag Shelter and Eco-Village: Manual-How to Build Your Own with Superadobe/Earthbags describes a continuous earth bag system to construct emergency 'behive' shelters
- Eco-Beam and Sandbag Homes A sand/earth bag house style with a timber frame
- Earthquake Relief in Pakistan using sand bag construction
- Tubular Knit fabrics for composite material reinforcement suitable for testing if weave is open enough
- Circular Knitting Machines over the years, some are very simple
- Toy tube knitting machine instructions showing the basic simplicity of the mechanism
- Three dimensional seamless garment knitting for just in time production of individually or small batch customisation
- Hose reinforcement knitting machine and knitting process Describes various standard techniques well in the preamble
