happy7
07-28-2014, 12:38 PM
I have an RCBS Promelt that I use for 50/50 alloy. I had put WW and pure in the day before and let it freeze full of lead. I turned on the pot next day and went to some other tasks. When I came back, the pot was still full of unmelted lead but there was a cone of lead from the base of the pot to the spout that was probably 7 or 8 pounds worth. But the pot was still full!
Eventually I worked out that the pot had melted the lead on the botton of the pot. All I can figure is that the alloys stayed pretty seperate and the WW must have been on the bottom and melted first. Some type of thermal expansion must have been responsible for the unmelted lead at the top fo the pot lifting the valve and letting all the melted lead out on the bottom. What I don't get is how the spout was warm that quick before the lead on top was melted. That has never happened before. Even accounting for the different melting temps of the different alloys, I wouldn't have expected that.
It was a heck of a thing to get it resolved. Without lead at the bottom of the pot, the lead at the top would only get warm. It would not melt. I tried first to drill, but that didn't seem like it would lead to a hole big enough to get molton lead to the bottom. Then I tried melting the lead from the top with a propane torch but that didn't get hot enough to really do anything. Fortunately I also have oxyacetelene and a couple minutes with that finally melted the lead and it ploped to the bottom. So problem is solved, but it really was a strange thing. It really felt weird looking at a full unmelted pot of lead and a cone of lead that just melted out of it. At first it just didn't add up.
Eventually I worked out that the pot had melted the lead on the botton of the pot. All I can figure is that the alloys stayed pretty seperate and the WW must have been on the bottom and melted first. Some type of thermal expansion must have been responsible for the unmelted lead at the top fo the pot lifting the valve and letting all the melted lead out on the bottom. What I don't get is how the spout was warm that quick before the lead on top was melted. That has never happened before. Even accounting for the different melting temps of the different alloys, I wouldn't have expected that.
It was a heck of a thing to get it resolved. Without lead at the bottom of the pot, the lead at the top would only get warm. It would not melt. I tried first to drill, but that didn't seem like it would lead to a hole big enough to get molton lead to the bottom. Then I tried melting the lead from the top with a propane torch but that didn't get hot enough to really do anything. Fortunately I also have oxyacetelene and a couple minutes with that finally melted the lead and it ploped to the bottom. So problem is solved, but it really was a strange thing. It really felt weird looking at a full unmelted pot of lead and a cone of lead that just melted out of it. At first it just didn't add up.