No-weld downdraught gasifier #1

Much is made of wood gasifiers being useful in emergencies. However, most are made in today's time of relative plenty. Constructors have ample time to source materials and then weld them together with state of the art equipment.

What if we were in an emergency? What if the materials available were not of a high grade? What if welding facilities were either not available or inappropriate given the materials we had? All of these questions made me think of building a no-weld gasifier, using common materials that anyone might have and tools that could easily be found.

In these times of dwindling resources, scrap metal is snapped up by scrap dealers and is hard to find. In an emergency, looking for quality scrap metal might not be an option. Here are some typical scrap tins that you might find in your house or on a rubbish tip.

Tools used were the kind that can either be found around the home or easily procured. No welding was permitted so fixings either had to be bolted together or merely rested on top of each other. Sealing to prevent gas escaping or air getting to where it shouldn't be had to be done with fire cement, which can be found in most hardware stores.

The larger tins are 20-litre vegetable oil drums and are ideal for building the main housings for a gasifier. These drums can easily be cut with tin snips but care must be taken when cutting thin steel as any jagged edges can easily scratch your skin. The metal will not clean and any dirt can enter wounds and cause infection.

This photo shows the top cut off a drum. A serrated edge can clearly be seen.

Serrated edges can be cut into tabs and then tapped down so that no sharp edges are in harm's way.

A firm surface under that part of the drum being tapped prevents the drum being put out of shape.

The result is an open-topped drum that can be used to house the combustion chamber of a gasifier. The fitting at top left of the drum is a tank connector. Any wood gas produced will be sucked out through this port.

Close-up of the tank connector. Connecting it is simply a matter of making a hole in the drum and screwing both parts of the connector either side of the drum wall. No welding required.

In the next section we will build the combustion chamber that sits inside this gas collection drum.

No-weld gasifier sections:

#1 - Introduction - materials and tools, building the combustion chamber shroud

#2 - Building the combustion chamber