by Jason Becker
So the Camera Guy broke the handle off of his cast iron skillet. I have repaired several different pieces of cast iron throughout my welding career using a different approach than most. I was taught this method by my old welding instructor in high school and have used it on many cast iron repairs and have never had any issues.
Although I can't really explain why it works so well I just know that it does in fact work.
Anytime you are to do a cast iron repair, you want to thoroughly clean the material, especially items that are used around grease and oils. Because cast iron is porous, it can retain any hydrocarbons it comes in contact with. The best cleaner I have found to do this is dechlorinated brake cleaner. It comes in the green can. You do not want to use chlorinated brake cleaner because when chlorine comes in contact with extreme heat and UV rays it produces hazardous fumes that are potentially fatal if inhaled.
I prefer brake clean over acetone because acetone doesn't really remove grease, it kind of just smears it around, its fine for newer materials but on severely dirty surfaces acetone just isn't as effective. Brake clean on the other hand, gets rid of everything and has become my goto for inservice repair cleaning.
Once the materials are thoroughly cleaned, I put the pieces back together as best I can to its original fracture lines. I take a nickel99 welding rod and break the flux off of it and sand it down to bare metal. After that, I'll put a couple small tack welds on the piece, these will most likely break because we haven't done any preheating yet. This is to be expected, I only need the tacks to hold long enough for me to grind out the cracks in the material. I then use a small burr bit and a Dremmel or air tool to grind along the cracks in the material. If the cracks don't terminate at the end of the material, you should drill through the material to prevent the cracks from going any further. I usually grind about half way through the material on each side of the crack.
Once this is done, I will preheat the cast iron to 350°F. Preheating can be done by whatever convenient method you have available. I usually use a torch and a rosebud but in this video we used a propane grill, you could also use a stove or a charcoal grill as well. Ive even heard of people using a small camp fire for preheating cast iron.
As soon as you hit the 350°F mark, you want to get to welding as soon as possible, remember the piece is HOT!!! so take some preventative measures to prop up on the material, heat wrap and wood are great choices to keep you from getting burned. Once you're propped up, start welding, you will notice that the nickel99 doesn't flow as well as smooth as other types of filler metal, it seems a bit thicker than most other wires. However, it will still yield a pretty decent weld.
Once everything is welded up, you will need to do some post weld heating on the item. You can use the same method you did for preheating. If you are using a torch, you can get it up to temp and then place the item in play sand and cover it up. You want the piece to cool down very slowly. Rapid cooling or lack of post weld heat treatment can cause the piece to crack again and then the process starts all over again. If you choose an oven, just pop it back in and slowly decrease the heat and then you can eventually shut it off and let it sit in there until its back to room temperature. I prefer to use a charcoal grill if I can. With this method, just leave the part inside and cover it with a lid until everything burns up and the grill meets the ambient temperature outside.
As I said, this is just my favorite method that I have used with great success in the past, there are several other methods out there. Find what works for you and try it out. I hope the video and this blog were educational and helpful to you.