Hi John,
All the burners are the same construction; namely a 28 mm coper tube stop end with a short length of 28 mm copper tube hard soldered inside to create a shoulder for the heating element to rest on. A 1/4" K&S brass tube goes through the side of the stop end to deliver the gas/air mix They is no difference at all between the burners except for their height, the highest being the ceramic and the lowest the straight mesh, you can guess where the other is? The ceramic element as bought is around 12 mm thick which I cut in half to 6 mm but even then it is nearly twice the height of the mesh burner. The attached photograph shows a ceramic burner along side one with the perforated steel with mesh underneath it, I cannot find the mesh burner, though it was made for R&D I might have used it; in any event it is about the same amount lower again. Why is a lower burner more useful? Well the vertical boilers for the model locomotives I play with don't have a large water capacity, so the lower the fire box the better. There is less work in the mesh burner as you only have to cut the mesh, the most work has to be the perforated steel burner. I cannot remember how the boiler was held and as yet I cannot find it. It might have got used along with the burner. I will see what I can find.
Take care Tony.
