Cast Iron Welding
We want to share some truths about cast iron welding with you. These truths are easy to understand, extremely important to know and yet, ironically, hardly known in the welding world.
About 40% of the casting repair work that we perform in our service department is performed by some type of welding procedure. Even though we are the world leader and only complete supplier of metal stitching supplies in the world, we are also the only company who will actually tell you the truth without bias. Some repairs require oven welding and some require metal stitching.
The most important thing for you to understand is that electric welding on cast iron is actually the very worst decision you could make to attempt to repair your cracked cast iron part. If you want to make a complete mess of your part, go ahead and arc weld it with nickel rod. Cast iron cannot stretch and withstand the contraction and hardening caused by cast welding with preheating below 1200 ° F. The brand of welding rod does not make a very big difference. It's the heat that causes the changes to the cast iron itself. Sure the nickel weld is machineable but the cast iron will become as hard as a drill bit or tap and therefore will prevent the proper machining that is often required. 50% of the casting repairs we see have been arc welded on with disastrous results often costing the owner at least twice as much to repair properly. Cast iron welding should not be attempted even by experienced welders without years of high temperature oven welding training. Cast iron requires preheat of at least 900 ° F. for brazing and 1300 ° F. for fusion welding.
If you want to know why and what the correct way is, read on.
Before we get right into the facts, we need to develop "clout" with you. If you don't already know our company, and the wealth of experience that is the foundation of our knowledge, you might be tempted to discount the information we want to share with you. Therefore this page is devoted to explaining the reasons you should listen, learn and prosper. If you already know us and have faith in us, skip to the links at the bottom of the page. Gary J. Reed is the inventor of the patented processes and developer of the proprietary products and procedures used and manufactured by LOCK-N-STITCH Inc. For over thirty five years he has amassed his hands-on casting repair experiences: successes and failures, testing and developing, compiling metallurgical data and results. No one else has contributed more or has had more experience than Gary. Many of the competitors of our service department purchase their supplies from us. Over the years Gary has personally welded over 5,000 castings ranging in size from less than one pound to over twenty tons. He has trained hundreds of people from all over the world. As of October, 2005, Gary has twenty US patents issued and many more foreign patents either issued or in the process of issuing, as well as many other patents pending in the US and abroad. His technologies have been used in millions of successful repairs.
Because of his experiences and his ability to teach others, Gary Reed is considered by many to be the most qualified person to render an opinion on the realities of what happens when heat is applied to cast iron.
Since one person obviously can't do it all, the company of LOCK-N-STITCH Inc. has grown to fill the increasing need for good information and great products for crack repair. LNS is a dedicated manufacturer. We manufacture all stitching and thread repair tools and supplies that we sell including our patented taps. We have a modern CNC machining and grinding facility with highly trained machinists, programmers, inspectors and process control management personnel. But we started from a repair shop and we are still a repair facility today. Our repair technicians are the ones you talk to when you call for technical support. And can you think of a better research lab for a manufacturer than to use its own products on a daily basis? If it doesn't work for us, it won't work for you. We test and prove Gary's products and knowledge with every repair we perform. Every satisfied customer of our service department helps us satisfy the customers of the manufacturing department. LNS provides the right tools, the right answers, the right experience and the right advice when you have a cracked or damaged casting.
Read the following information thoroughly. Ask yourself if it doesn't ring true. In fact, once you really understand it, you'll realize you knew most (if not all) of this already. You just hadn't put it all together in a conceptual package. Now you can take your own experiences and interpret them just a little differently. When you apply your new understanding to the concept of welding cast iron, you won't make mistakes ever again.
Cast Iron Welding Supporting Material
- Watch this powerpoint presentation for an in-depth look at cast iron welding. (PPT - 29.2MB)
- GRMC White Paper (PDF - 1.59MB)