ECN Forum Forums Code Related Discussion NEC & other Code issues Exothermic Welding or Irreversible Connections, Comments?

Whatever else is in that stuff must want the Cu's Os pretty bad. I feel like I have an answer to every question but one. How hot does it get? Does anybody know a temperature?

What are they gonna do with all those zinc pennies when a cent doesn't cover that value anymore? I used to drop them in the street because they interfere with getting to useful coins for parking meters. I guess I was littering.

It sounds like a thermite reaction, similar to what is sometimes used to weld railroad rails. Probably copper oxide and aluminum powder.

 
OK, Joe, I can’t possibly resist swallowing the bait, hook, line and sinker on subsurface ground-conductor jointing. This became a ‘hot’ subject at my worksite prior to retirement. There was lots of boilerplate in facility standards and specs there, given lightning protection, station and unit-sub ground mats, and research work where low-impedance grounding was taken very seriously. {4/0AWG 7-strand bare copper can be a bit taxing to deal with.}

No offense is meant, but for maybe 50 years, Er*co and Th*rmow*ld seem to have had 98% of the North-American market cornered, precipitating an attitude towards any other approach. When B*rndy [and others since] came out with their (zero-BTU) Hygr*und YGH/YG components, the exo guys were spitting blood over a genuine threat to their long-held notion that suggesting a replacement for exothermic welding was blasphemy, and could not conceivably be expected to perform on a par with their product—for at least the next 200 years.

IEEE standard 837 [table of contents (only) at http://standards.ieee.org/reading/ieee/std_public/description/subst/837-1989_desc.html] sort of leveled the playing field towards requirements/capabilities/expectations for high-performance grounding connections in power-delivery applications.

Exothermic welding is wonderful for the closet pyromania in electricians, but can present some administrative convulsions in the “uninitiated”—inexperienced in anything beyond mundane electrical-construction practices. Hydraulic-compressed jointing materials are typically furnished with an NRTL “blessing” behind them, and given simple effort with the right tooling, can be consistently and extremely reliably applied, even in dense fog and high wind. {I’m not sure that’s the case for exo… but for their installation, the $10 “shoot-a-lite” was manna from heaven.}

Personally I think cadwelds are better. Have not had one yet get corrision in it as I have with crimps. Yes they can be a pain in the rear end to use if you are not careful and not completly prepared for the work conditions. But I have sucessfullly fired them in rain storms -- used a welding blanket as a tent.
Usually get 75 to 100 shots from a mold use a plastic cleaning brush instead of the steel brush the manufacturers recomend. Clean after every shot while mold is warm- cool enough to touch.
A good cadweld is a matter of good preparation and patience.
The molds are the most expensive part and need some care.
The temp of the shot gets over 1000 F enough to melt the shot
by the way I use scrap copper wire cut up small when needed the penneys are in the change jar.

Nesparky, I used to do class C mil spec soldering. Condition and prep is everything when you're going to melt things. Oxidation is the enemy. Except with this stuff you start with oxidation and go the other direction. I just love that.

And I think you're way under on temperature.

I agree on the heat. Copper melts at almost 2000f.

The problem with welds are the number of different combinations of wire sizes and tap configurations.

This is not all of our molds,
yet even including the rest, it seems as though every job has atleast one combination we don't have.

Roger

Roger how did you get in our warehouse.

I should get a picture at our place the shelf holding all the molds is bowing down from the pile that always grows.

Bob

Bob, you mean to say your company has the Benfield model 101 mold shelf too?

Roger

"I guess the T men are after me too. I use pennies for shot pin washers." - KO slugs work well for that too.

As for Cadweld, I have only used them a handfull of times. And only when required to do so. (Some moron cuts that wire sticking out of the foundation...) I don't like it very much, its like emptying out a roman candle, and road flares out and trying not to make a bomb out of it. I have had some spit back at me. Flying blobs of molten metal, not my cup of tea.

I heard somewhere that they now make dispoable molds. 1 time use. Nope, just checked not yet... They did however make a sort of universal mold... http://www.erico.com/products/CadweldMulti.asp


And some inspectors get wierd welds and crimps, about hidden corrosions, imperfect welds, what die you used, and its spec's. There used to be one that would want to watch you do it. A real pain...