Hi everyone
I have'nt done an iron melt for a while so I fired up the furnace, have a look at the video
A few people have asked me why I use waste oil for melting cast iron. For many years I was using propane to melt cast iron but there was two problems using it.
1. Liquid propane tends to get very cold when it evaporates to gas and so less gas is available for the furnace. I used to pour hot water on the propane bottle but after awhile the same problem would come back.
2. You have pay for propane. I used to go to the local scrap metal yard and get propane bottles that were out of date with gas still in them but it was not a reliable supply.
So in 1993 in workshop where I was working had a steam cleaner that had a flash boiler that used kerosene to heat the boiler. It used a blower to atomize the kerosene so I copied the design and it worked so well I never used propane again for melting cast iron. There is one regret that I have is that the jet was welded in so if I wanted to experiment with jet sizes I would have to start all over again. The jet size about 0.070” and at the time it was the smallest drill I had. So many have copied my design and would not be melting cast iron today unless they saw my furnace running.
These designs have been around for many years and get rediscovered again even more so now that the internet is so popular.
I was curious to know which was better to melt cast iron and the answer is both propane and waste oil reach the same temperature in my furnace and owning a pyrometer was easy to prove. It also takes about the same time to melt. After each melt I weighed the propane bottle and the waste oil bottle and found that waste oil is slightly more economical than propane gas.
You are all so lucky to have this forum and the internet, back when I started experimenting with waste oil I was on my own. For those who are experimenting with liquid fuels a important fact is you have to remember is a liquid by it’s self will not burn the drops have to be small enough to be vapourized to a gas by the furnace and then it will burn.
A friend Emailed me a week ago of pictures of his waste oil furnace he built using the artful boger design. He said it melted cast iron but was not hot enough to fill up the molds. I looked at the links at the artful bogders site of people who have built their furnaces to his design. Most of them I could tell that their cast iron was not very hot. His video of casting a small cooking pot was very hot cast iron. The point I am trying to get across is that you need hot cast iron. There are many reasons why a furnace will not get hot enough. I will list three mistakes that beginners make.
1. The higher temperatures are needed when melting cast iron. At these temperatures you loose heat faster so good insulation is needed.
2. To reach these temperatures fuel has to be burnt at a faster rate than melting non ferrous metals.
3. Too much air and not enough fuel the furnace will not get hot enough
Too much fuel and not enough air and the furnace will not get hot enough
I could say it is soooo easy to melt cast iron but you need to understand that melting non ferrous metals is alot easier but cast iron needs more effort and knowledge. The same thing can said about waste oil burners.
