Home made bellows

I recently spent the day constructing a pair of hand bellows. The aim is to test out different variety of bellows over the coming months in order to gauge their effectiveness in a temporary or basic forge set up. Hopefully through testing out a broad range of designs used by various cultures around the world I will be able to settle on one that best suits a temporary forge set up, giving flexibility and ease of use in our woodlands. Although many people starting out experimenting with blacksmithing will often go for a small electric  pump or hair drier as an air flow I have personally tried to steer away from this in favour of a more traditional methods that feel more in-keeping with the process. I will admit thought that like all traditional skills I have had those moments where I have appreciated the development of modern fans and pumps and just how convenient they can be. That being said there is a fantastic sense of connection to your work and achievement of the end result by working through the same problems and difficulties that people would have faced in the past. It requires you to engage with the whole process rather than simple focusing on the end result and getting there as quickly as possible.

For this project I decided to opt the design seemingly popular throughout the Dar Ages and used extensively by those masters of metal work. The Vikings. This style of bellows has evidently remained popular and is still in use by many people at home with stove and wood burners. The simple reason for this is that it works, is fairly straight forward to construct with only basic woodworking tools required. The double bellow design has several key advantages over simply opting for one commonly used at home despite the doubling of the work.

  • Firstly with a bit of practice the two bellows allows for a constant air flow into the forge. Meaning the desired temperatures can be reach faster and with far less effort.
  • Secondly once a rhythm has been established the alternate flow of air from each bellow prevents hot ashes and coals being drawn back into the other which would result in holes be burnt and altametly loss of your hard work.

Below I have outlined the basic process of creating a simple and effective bellows for some home forging. Hopefully this can serve as a guild to any future forge making projects.

The first step was to profile the top and bottom boards that will form the structure of your bellows. Mark these out on your material of choice, wood was the obvious traditional option and my suggestion would be to use what you have to hand. Ply wood will work fine also as long as it is thick enough to attach material to later when sealing the bellows.

Cut these out to shape, I decided on a teardrop shape to utilise all the material I had. Marking one up and cutting this to the desired profile it then served as my template for the remaining three boards needed.

[One board cut with the other three ready to go]

The next step was to measure and cut out the outlet for the air flow towards the forge. For this I simple uses a section of 2×2″ and drilled a hole through it the same diameter as the metal piping being used. These sections can be carved more elaborately from wood out of naturally occurring Y branches though this will involve more tricky drilling and carving to get a good connection.

[2×2″ with holes drilled through to house ouflow pipes]

Once you are happy that all the pieces are cut to size you have the three mains wooden components completed and ready for construction. The air flow section can now be secured to the boards intended for the base of the bellows and then set aside while we consider the holes for the air intake on the top boards.

I decided that I would go for an three hole design rather than a simple larger hole but either will work just as good. To ensure these three holes sit square on the bellows draw a centre line up the length and decide on where you wish for the holes to sit. I measured 4 inches down from the handle to score the first central hole. From this I marked 2cm down the centre line then two 2cm out either side to mark the 2nd and 3rd hole.

[Measuring the three holes for the air intake]

Following the old wood working mantra of ‘measure twice cut once’ make sure you are happy with the position of these holes and they are square to the board before committing to drilling. A tip on drilling these neatly as your will want to draw your workings on what will be the inside of the board. Start to drill through while regularly checking your progress until you notice the central tip of the drill piece has protruded through the outside of the board. At this point stop and finish off the hole by drilling back through from the outside. This will ensure you have a neat and smart finish to the board with minimum effort.

Once the three holes have been tided up secure the valve onto the underside. This is achieved through the use of two pieces of buckskin or thin leather, one diamond shaped the other a rectangle. The diamond shaped piece was secured on either shorter edge, pulled taught across the holes. The rectangle was then placed over this and secured on the four corners so as to create a good seal when the bellows are closed to pump air into the forage.

[Overlay of the two pieces of buckskin, ensuring a good seal whilst forcing air into the forge]

We are now close to the point where we will be attaching the leather to the top and bottom boards. Before we do though hinge the top board onto the bottom section by securing the hinge onto the 2×2 inch piece that will hold the out flow pipe during use. Make sure that the screws or nails holding the hinge have not protruded into the hole that will house the metal pipe.

Now that you have the two wooden sections attached at the hinge and the vales are in place it is time to attach the leather around the bellows to make them air tight. I started by attaching the leather to the bellows at the nozzle end of the bottom board and working around to the handle end and finally round to the other side. Then pull the leather sheet up while holding the bellows open fully to gauge where to leather would site on the upper board. Before securing the top side of the bellows I made sure the leather is securely fastened around the inside of the nozzle piece. This way you will end with a neat and professional look to your bellows.

Once happy with the front double check the measurements along the top board and start to tack it round from one side to the other. Take care not to stretch the material as you go round otherwise there is a risk of gathering it along the far side of the board. A helpful tip with this is to tack the ends and the centre first before committing to the whole edge. This way it will prevent gathering while allowing you to see that the leather is fitting correctly.

If you have some extra strips of good thick leather it may be a good idea to reinforce the edge of the bellows while you are tacking them on. This sandwiching will also help in the air tight seal we’re trying to achieve. If you don’t have any to hand though or are trying to keep costs down this is not essential.

At this point we should be looking at two bellows that are completed minus the handles and the pipes for the air flow to the forge. For the handles there are many options available to you regarding the design, some of which are built into the top board its self, with others attached later. I opted to attach mine separately to maximise the size of my bellows. For this I decided to utilise natural strength of a branch fork to give me a secure attachment and a nice finish to the bellows.

To effect a constant air flow into the forge and to fully utilise the double bellows we need to establish a connector between the bellow outlets so that we have just one inflow of air directly in the forge. This enables us to avoid the need for double values and a host of other complicated additions. By having both bellow joined and sharing the same outlet into the forge we can, with a steady rhythm, establish a constant air flow and eliminate the risk of hot ashes and embers being sucked back into the bellows and burning through the leather whilst it is reflating.

To keep the traditional feel to the bellows I decided again to utilise a natural Y shape branch as the connector of the two outlets. This was drilled out along each limb with the holes joining at the centre of the Y. Once the three pipes are installed, making sure that they have tight fit the bellows are ready to test and blow life into the forge!

As I outlined at the beginning there are a wide range of options when it comes to bellow styles. Different cultures have come up with various different methods to maintain a constant air flow into their fire or forge to achieve the desired temperatures for basic blacksmithing of metals. Using bellows of this design it is possible to raise the forge up to temperatures needed  to heat weld metals together, so for simple blacksmithing projects they should serve admirably.

Danny Hodgson
Full time Instructor

 

References:

  • Making Bellows, Manaraefan Heered, Vikings for all occasions, no fire too hot: http://www.manaraefan.co.uk/index_files/Page408.htm
  • Lodin’s Primitive Forge and Tools, Fjellborg Vikings: http://www.fjellborg.org/LodinsForge.htm