Explanation for the Material and Dimension Input Page for Constructing a Portable Metal Rocket Stove with Either a Cylindrical or Rectangular Combustion Chamber Use this page to input the appropriate material dimensions for constructing a portable metal rocket stove with either a cylindrical or rectangular combustion chamber It is absolutely critical to measure the pot exactly. If there is even a slight error in the pot measurement then the plans produced in this guide will be worthless. Pot dimensions. Use mm 1. Input pot circumference: use a soft tape to measure the circumference of the pot at the widest point below the handles. Circumference of pot in mm Height of pot (Pot h) in mm mm Height of pot to bottom of handles in mm (if the stoves does not have a handles, measure to just below the top pot lip) The design tool will calculate the pot volume and the corresponding stove size
1. Choosing the Proper Metal Components Following information is intended to help you choosing the appropriate metal components for your stove. For example it is possible to use 1.4-2 mm thick mild steel sheet metal. Input the thickness that is available and cost effective. Larger stoves should be constructed with 2 mm thick mild steel whereas smaller stoves should be constructed with thinner mild steel Sheet metal: thickness of sheet metal for stove skirt and body. Use 1.4-2 mm Angle iron: Use either 3 or 5 mm thick The height of the angle iron can vary from 25 40 mm Round bar: Use 12 mm for base 10 mm for Pot Stabilizer and Wood Support not input). Legs and pot supports. Use 40 mm wide by 1.5 5mm thick square tube(do Shelf: use mild steel or stainless steel 3 5 mm thick (do not input). Legs and pot supports. Use 40 mm wide by 1.5 5mm thick square tube For pot volumes greater than 75 0 L use 3-5 mm thick square tube. For pot volumes less than 75 L, use 1.5-3 mm thick square tube. Thicker square tube is always preferable to thinner square tube Select a Combustion Chamber Style It is possible to construct a rocket stove combustion chamber with either a rectangular shape (see photo below left) or a cylindrical shape (see photo below right) A
The rectangular rocket stove combustion chamber is usually preferable to the cylindrical combustion chamber. However, the suitability can depend upon the materials that are available in your region. Please read over the following options and then select the combustion chamber that seems most suitable. Once chosen, a custom set of plans will be produced that are designed specifically for the selected combustion chamber. Options are listed in descending order of preference. *Note: if no input option is offered for the liner thickness than the 5 cm thick constant will be used as the default Rectangular Rocket Stove Combustion Chamber Options Option 1 Insulative Refractory Ceramic Bricks Example: clay/grog/sawdust bricks that are made and used in Malawi. Production of these bricks requires access to: a refractory plastic clay sufficient quantities of fine biomass a high-temperature kiln (1000 C-1300 C) a lower density(<.7g/cc) brick for the combustion chamber and a higher density (> 1.2g/cc) brick in the feed chamber *Liner thickness = 5 cm brick (constant) Option 2 Non-Insulative Ceramic Tiles Surrounded by Insulation Example: ceramic liner surrounded by volcanic pumice that is used in Ethiopia. Production of these bricks requires access to: a nonflammable insulative material (i.e. pumice, rock wool. See appropriate insulation**) A refractory ceramic liner consisting of: A low-density (<.7g/cc) liner for the combustion chamber surrounded by insulation A high density (> 1.2g/cc) liner for the feed chamber surrounded by insulation *Liner thickness: 2-4 cm
Cylindrical Rocket Stove Combustion Chamber Options Option 3 Insulative Ceramic Doughnuts Example: clay/grog/sawdust donuts that are made and used in Malawi. Production of these bricks requires access to: refractory plastic Clay high-temperature kiln (1000 C-1300 C) use a lower density(<.7g/cc) brick for the combustion chamber and a higher density (> 1.2g/cc) brick in the feed chamber *Liner thickness: = 5 cm width/thickness (constant) It is also possible to use the same low density doughnuts for the entire chamber. With this option, line the inside of the feed chamber with a durable abrasion- resistant high density liner. 1 cm thick r Option 4 Non-Insulative Ceramic Pipe Surrounded by Insulation *Liner thickness: 1-2 cm Example: a ceramic liner surrounded by volcanic pumice that is used in Ethiopia. Production of these bricks requires access to: a nonflammable insulative material (i.e. pumice, rock wool. See appropriate insulation**) A durable refractory ceramic liner: A high density (> 1.2g/cc) liner for the feed chamber/ combustion chamber surrounded by insulation
note: a highly competent ceramicist with access to refractory plastic clays is required to make this type of monolithic refractory pipe. Unless these are available we recommend against using this type of combustion chamber. Option 5 High Temperatures Stainless Steel Surrounded by Loose Insulation A 1-3mm stainless steel combustion chamber made from either: 309 stainless (rated for1050ºc) 321 stainless (rated for 850ºC) 310 stainless (rated for 1100ºC) liner This liner should then be surrounded with appropriate insulation** (not shown) The feed chamber entrance can be either circular or square *Liner thickness: 1-3 mm Option 6 A Refractory Cement/Vermiculite or Refractory Cement/Pumice Insulative Mixture Liner thickness = 5 cm brick (constant) * Liner Thickness Front view of rocket stove feed chamber/combustion The drawing right shows a schematic front view of the feed chamber/combustion chamber. The grey area represents the insulation which is a constant 5 cm thick. The brown area represents the liner thickness which is 1mm -4 cm thick. The liner thickness will depend upon the durability of the material that is used as well as the
predicted use of the stove. For example if the stove is going to be used roughly (as it might be in a prison) than the liner should be thicker. Also if there are questions about the durability of the material, than the material should be made thicker to reduce the chance of breakage liner thickness: 2-4 cm ** Appropriate insulation The liners outline in o Ption 2, 4, and 5 should be surrounded with an insulative layer. Examples of appropriate insulative materials are: Loose volcanic pumice high-temperature Rock wool Sawdust (or other fine biomass) and clay ( 6 parts sawdust to one part high-clay content soil) Sawdust (or other fine biomass) and cement ( 8 parts sawdust to one part cement) Loose, non-compacted, dry wood ash Any material that is low density (~5 g/cc) and fire resistant can be used. Do not use sand, brick or other heavy/ materials as they have a relatively high density