I have recently been given / inherited an old forge so that I can start blacksmithing. It is a William Allday & Co "Alcosa" forge. The main forging area is a 24" drum filled with 4 bricks of some kind, with a small air hole in the centre. Researching around, William Allday & Co were in business from 1948 to 1984, and the wiring had a green Earth wire, so it predates 1976 so this forge is at least 45 years old. Interestingly they are apparently unconnected to Allday & Onions, this was a separate Allday family (or at least a different branch of it.
The air is supplied by a very old and very broken electric pump through a small 5/8" hole under the drum. There does not appear to be anyway of preventing clinker and ash building up in the hole in the drum, but as I was never able to see the forge in use it may "just work". The drum sits on the stand and the spigot the stands up on the stand frame pokes into the hols in the bottom of the drum. The inlet side of the spigot on the stand is only 3/8". The original motor was rated as 3.8CFM (0.1 m3/min). So this seems to be a low volume, high pressure kind of airflow rather than the standard forge setup which is high volume, low pressure. I did try to use a hair dryer to provide the airflow, but it died after about 30 seconds due to overheating as things like hair dryers are designed to do high volume, low pressure.
When I look around for forge blowers, they are all 2-3" outlets, which makes me think that they are high volume, low pressure designs, so I am guessing that if I try to use one I will overheat it as I am not going to be able to push all of that air through the 3/8" tube.
Has anyone seen / used this kind of forge? All of the other "Alcosa" forges I can find online have all had a large diameter blower on the side of the forge and are side blown.
Does anyone have any recommendations as to what kind of air supply I should be looking for. I was thinking a small pump used to blow up inflatable beds, as they are low volume / high pressure, but I am not sure that any of them would be rated to run continuously for any length of time as they are only designed to run for a few minutes to blow up a bed.
Once I can get a fire going, I will then look at some kind of hood and chimney so that I do not have to carry it outside to use it.