Danny Phillip Doeden
Member
- Location
- Southeast Nebraska
I have seen the term "exothermic welding" several times and I was wondering if anybody could tell me what it is.:smile:
exothermic welding
- Thread starter Danny Phillip Doeden
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bphgravity
Senior Member
- Location
- Florida
I suggest you perform a google search and do a little research on your own.
sparkyway
Member
- Location
- South Central Ky
Yes, google it and it has tons of good references and pictures. Typically its a permanent weld for metals using a ceramic device with ignitable powder to generate a hot spot to join the wires. Its used for a lot of grounding systems and is often required in job specs.
I'm having second thoughts about including exothermic welding in my specs. Partially because of a sales call by a compression connector guy, and partly because I once watched a contractor try to make an exothermic connection. It seemed like something that takes some experience to do.
To make an exothermic connnection, you put a mold around your wire, fill it with something that I assume is gunpower and a welding metal, and light it.
Well, the electrician had to find someone with a Zippo. Then when he lit it, it melted the top of the Zippo, and burnt his hand as the stuff sprayed out of the mold. After a few choice words, he took the mold off, the wires promptly fell apart. I'm told that a good connection with this stuff looks just like a bad connection, and electricians usually just hit a connection with a hammer to determine if its good or bad.
Compression connectors are starting to sound a lot better.
To make an exothermic connnection, you put a mold around your wire, fill it with something that I assume is gunpower and a welding metal, and light it.
Well, the electrician had to find someone with a Zippo. Then when he lit it, it melted the top of the Zippo, and burnt his hand as the stuff sprayed out of the mold. After a few choice words, he took the mold off, the wires promptly fell apart. I'm told that a good connection with this stuff looks just like a bad connection, and electricians usually just hit a connection with a hammer to determine if its good or bad.
Compression connectors are starting to sound a lot better.
- Location
- Illinois
- Occupation
- retired electrician
Like everything you have to know what you are doing to make an exothermic weld or a compression connection for that matter. There are details for both, that if missed, will result in a failed connection.
charlie
Senior Member
- Location
- Indianapolis
Or an explosion. Such as leaving the mold for an exothermic welding assembly in an outside locker and the humidity is extremely high for a period of time. Firing a connection in a damp mold will created rapid expulsion of pieces of the mold and bits of molten metal into you and the surroundings. :roll:
exothermic refers to the type of chemical reaction that is taking place - it means that heat is release during the reaction (as opposed to endothermic). Most cadwelds use a type of thermite for the process, and as others stated, simple directions must be followed. We don't do a lot of cadwelding, so except for a couple of molds, we generally use the one shots, which are very economical, and come with a gunpowder type fuse to fire the reaction.
piece of cake
piece of cake
It is really a simple proceedure. They have kits that have have different size molds for the number of wires and different strenth powders for larger wires or thicker metal to bond to. Follow instructions and any first timer will look like a pro. Don't use a disposable lighter and DO use the proper gloves so you don't burn a hole thru your hand.
piece of cake
It is really a simple proceedure. They have kits that have have different size molds for the number of wires and different strenth powders for larger wires or thicker metal to bond to. Follow instructions and any first timer will look like a pro. Don't use a disposable lighter and DO use the proper gloves so you don't burn a hole thru your hand.
eric9822
Senior Member
- Location
- Camarillo, CA
- Occupation
- Electrical and Instrumentation Tech
Sorry but that was a dumb move on the electricians part. We use leather gloves and a long igniter to set these things off. As others have said, the installer needs to know what he or she is doing. Someone using a Zippo to ignite one of these things makes me think he lacked proper training on how to perform the task.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Erico has a new shot (poweder) and ignitor system, the powder and ignitor is combined into a metal cup, there is a battery powered electric ignitor and lead. No more metal disks and spark ignitors.
You push the button for a bit and zap it goes off.
You still have to dry out the mold and each type of connection takes a different mold.
For a few connections of the same type cad weld may be less expensive, the compression system has a higher first time cost due to the tooling.
That's one reason I liked to spec the exothermic welds. I feel like specifying compression connectors might exclude some of the smaller contractors who can't afford the tools.
charlie
Senior Member
- Location
- Indianapolis
Done correctly, exothermic welds are as nearly perfect as you can get. The amount of training is minimal but very necessary. If the molds are not cleaned out properly, the interior can be damaged or they wear out too fast. Also, the user can be damaged beyond repair with great pain.
By the way, I have used the penny trick to stretch a mold's life. Instead of using the small steel disk in the bottom of the reaction chamber, I have placed older pennies (I used only "wheat" pennies) in the reaction chamber to increase the copper in the weld.
By the way, I have used the penny trick to stretch a mold's life. Instead of using the small steel disk in the bottom of the reaction chamber, I have placed older pennies (I used only "wheat" pennies) in the reaction chamber to increase the copper in the weld.
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