Cast-Iron Furnace Build Using Partially 3D-Printed Molds

Looks like the whole putter is there, good job!

Jeff

 

Cool! Nice work!

 

Hey everyone, I've been using the furnace for quite a while and finally got around to taking some videos after getting a new camera. I've uploaded two relevant videos to YouTube, one details the furnace itself and the other is more relevant to lighting/running the burner but I'm using it on my forge.




Anyway, the furnace is holding up great so far despite not having a steel shell and having an extremely thin wall of refractory. I've done at least a dozen melts of brass/bronze and several of cast iron. The refractory has one major crack running vertically inside the main body of the furnace, but the wool and steel wire are holding it in compression and not allowing it to grow. The lid is also surprisingly in good condition even after multiple very hot firings with a lot of splatter, and does not appear to have sustained any structural damage. I've had the most trouble with the plinths cracking because they stick to the crucibles and then drop to the ground when removed from the furnace. I've used coal/charcoal powder between the crucible and the plinth every time, but it appears to lose effectiveness when the crucible is removed and replaced after charging/pouring. I've also had trouble melting cast iron. The first pour I did was excellent and the cast iron was extremely easy to melt. However, I haven't been able to replicate this success. I've now ruined two crucibles trying to melt cast iron because slag/oxide/unmelted cast iron sticks to the bottom of the crucible forming a hard mass that is impossible to melt or remove (even when getting the furnace hot enough to start melting the surface of the refractory). Not sure what I'm doing wrong and haven't had time to revisit the issue because school has started up (this time in-person) and I've had to leave my shop (read: happy place) yet again.

Just a quick update on this project for those of you who may be interested.

 

I think the best way to be sure the plinth doesn’t lift is to mortar it in a bit. I just used some refractory around the plinth base to lock it down. I used Blu-Ram. But any durable refractory should work. I also use 2 layers of cardboard under the crucible.

It is possible that your fuel-rich burn is unnecessarily rich and your lean burn is about right to a tic lean. Not sure.

Much progress made.

Denis

 

You can cut a small octagon of sheet cement to put under the crucible to stop slag acting as glue (Fibro in Australia) made by James Hardy Co., Denis has identified the comparable product in the USA.