# Exothermic Welding



## Joe Tedesco (Mar 25, 2007)

This was done with a battery as the source for ignition:

*Exothermic Welding* 


http://www.youtube.com/v/wduOAB_1ttI


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## HighWirey (Sep 17, 2007)

Joe,
Thanx for the U-tube link. I have been out of EC the loop for a while. Is that battery squib something vended commercially? I spoke to Erico Products about this problem years ago. Weren't interested. 
I have hated those exothermic welds forever. 3/4" x 20 foot rods (welded), and 4/0 everywhere here. Tired of running my men to the dispensary for an assortment of associated exo injuries. The men were careful and had PPE, but stuff happens, Murphy was here too.

A hint from Heloise here . . .
Years ago I built up a small PVC box with a small neon transformer inside. A 5-15P SO whip goes in to the box, a momentary pendant switch whip comes out, as do two pieces of GTO cord, one end connected to a home made electrode on the end of a piece of 1/2" PVC, and the other end connected to a 'welders' type big visegrip pliers, which also helped squeeze the sometimes leaky mold halves together. Hold the electrode near the starting powder, press the pendant, and wallah . . . instant fire, and no casualties.
Was it legal: I doubt it 
Mens take on it: priceless
Drawbacks: none - convenience power was usually available.

Best Wishes


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## Mountain Electrician (Jan 22, 2007)

HighWirey said:


> Joe,
> Thanx for the U-tube link. I have been out of EC the loop for a while. Is that battery squib something vended commercially? I spoke to Erico Products about this problem years ago. Weren't interested.
> I have hated those exothermic welds forever. 3/4" x 20 foot rods (welded), and 4/0 everywhere here. Tired of running my men to the dispensary for an assortment of associated exo injuries. The men were careful and had PPE, but stuff happens, Murphy was here too.
> 
> ...


Legal or not, still better than a bic lighter and a hole burnt right through the back of your thumbnail. 

Or how 'bout when the mold gets messed up and you have to drill it out and then use duct seal to keep the weld material from running out. Then don't forget the explosion of igniting a weld in a wet mold. Gotta love exothermic welding!


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## Andy in ATL (Aug 17, 2007)

Only being in the commercial end of things for 11 mos now, I had my first experience with this exothermic welding that you speak of.

I was truly impressed. This had to be one of the most dangerous things I've ever witnessed. I made homemade bombs as a youngster and that was safer this this witchcraft!:laughing: :001_huh:


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## Bkessler (Feb 14, 2007)

I have done it with the flint igniter that a plumber uses and never really felt unsafe, my problem was how hot the copper stays. I always touch it to soon. But a bic lighter does seem a tad dangerous.


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## Mountain Electrician (Jan 22, 2007)

Bkessler said:


> I have done it with the flint igniter that a plumber uses and never really felt unsafe, my problem was how hot the copper stays. I always touch it to soon. But a bic lighter does seem a tad dangerous.


Indeed it was. I certainly don't recommend it to anyone. I was younger (much) and a whole lot less safety conscious than today. More than once, which by itself is a good indication of how stupid I was, I burned the crap out of my fingers, the worst time being when a molten piece of copper burned all the way through the back of my thumbnail. Ouch! Dumb!!


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## HighWirey (Sep 17, 2007)

"is that battery squib something vended commercially?"

Looked at erico.com and sure enough they now do offer an electric squib, plus several new items (new to me).

We always had plenty of the OEM exo strikers on hand, but they quickly went flakey, and always put you too close to the spark'in.

Best Wishes


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## HighWirey (Sep 17, 2007)

"I made homemade bombs as a youngster"

So did I, but that kind of conduct will get you 5-10 in Woolworths now-a-dayz.

Ever try ammonium tri-iodide? Stuff was neat, with the purple smoke and all . . .

Experimenting in all fields (in the early days, way before my time) is what helped make this country great).

Best Wishes


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## micromind (Aug 11, 2007)

I absolutely detest cadwelding. There are two kinds of guys who cadweld.... the kind who have been burned by it, and the kind who will be burned by it. 

With all the safety garbage continually shoved on us it amazes me that this process hasn't been completely outlawed yet. 

I realize it's the only way to accomplish certain things, but there has to be a safer method. 

Please excuse the rant, I just finished a cathodic protection system that involved about 300 cadwelds of #2cu. to ductile iron pipe. The dies were handheld to the pipe, and due to the 'improved' design of the lids there was no possible way to light it with the lid closed. Even if I built the starter powder up to the edge, and held the striker as close as possible, it just wouldn't light. They lit fine with the lids open though.


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## HighWirey (Sep 17, 2007)

micromind,

Don't worry about your rant, I think you have a lot of brothers out here . . .

Had a job that required 1100 ! (yes, one thousand and one hundred) exothermic shots on what was called an SRG (signal reference grid - a thin 2" wide copper matrix under a computer floor) in an environment loaded with smoke detectors and people. Of course we had the local smokes turned off, burn permits out the wazoo, fire protection, and provided smoke ejectors to the outside of the facility, and still the project was a 'cluster F'. Everybody was bitching. Customer's engineer agreed that we had conformed to the contract requirements, and he was in a quandry. We finally used a prestolite torch with silver solder, and the project was completed in 1/4 of the time, with a whole lot less heartburn (or any other kinda' burn).
I certntly understand the reason for exothermic welding, but there must be some middle ground here somewhere.

Best Wishes


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## HighWirey (Sep 17, 2007)

"my problem was how hot the copper stays. I always touch it to soon"

Ever been to a doctor? Doc usually sez "well, don't do that"


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## Andy in ATL (Aug 17, 2007)

Witchcraft, I tell ya!:blink:


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## Mountain Electrician (Jan 22, 2007)

Actually, burns aside, I never minded cadwelding at all. A little sketchy doing it in the middle of a refinery, but still kinda fun.


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## brian john (Mar 11, 2007)

Over the years we have completed thousands of "CADWELDS" and to date I can think of no burns. We supply proper PPE for this work. Couple of scares, few bad welds, but other than that.


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## MDShunk (Jan 7, 2007)

I think most of my CadWeld scary moments were mainly due to worn out molds.


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## TOMWELDS (Dec 11, 2007)

We just recently purchased the equipment for making exothermic weld connections. With all due respect, the injuries that you're mentioning seem to be due to improper procedures. The kit comes with an ignitor that keeps your hands far from the source (i'd never use a bic lighter). Holding the mold during the process is pretty insane, they give you a holding clamp. Treat this stuff like 13kv...be safe.


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## brian john (Mar 11, 2007)

Our techs have heavy duty welding gloves.


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