Distribution Of Steam Vents
Once appliance makers started to nail down how to produce decent steam within an iron, next came an almost arms race of vents in soleplates.
Steam irons were advertised by the amount of vents as one supposes the theory went it provided more moisture for better ironing. However if one examines many commercial irons today their soleplates often resemble the "Steam-O_Matic" advert shown above. Either a small array of vents usually around the outer edge of the iron, or one central one at the head. Theory behind this design is that powerful steam dampens the fabric whilst the heat from the soleplate smoothes, dries and fixes the results.
Intersting tidbit about weight and electric irons:
Coming from using "sad irons" made from cast iron both most assumed electric irons had to be heavy in order to give good results. However research by Proctor (later Proctor-Silex) showed that long as the iron had proper heating power (around 1000 watts) heavy weight wasn't necessary, especially with a good supply of steam.
Of course there is lightweight and there is heavy. Housewives and others doing ironing varied as to their preference. Hard to believe but there are still professional ironers in France (and one assumes elsewhere) that are using sad irons heated on stoves.
Find for heavy linen and or cotton an iron around four to five pounds is good. Three or so is ok for lightweight things such as cotton dress shirts and so forth. It also depends how much ironing one is going to do at a go. Good results or not dragging a five or six pound iron back and forth for several hours of ironing is just plain hard work.
