[TheForge] yurts, spelter sockets

[Steve howell]

 Dave,
I get the digest version and forgot to chop the quality rant in my reply. No wonder it didn't make it through the filters.
Anyway- For those that asked, the spelter process is roughly illustrated at our Sahale bridge site www.sahale.com<http://www.sahale.com/> under the Meriwether bridges. We use 80 year old Tiger (USS) brand procedures and they've worked well so far. For bridge bowls and sockets we use Houston Structures out of Hubbard, Oregon http://www.ulvencompanies.com/houston.html<http://www.ulvencompanies.com/houston.html> Two things are very important in the process. Number one is the proper 'brooming' of the strand. This is a manual process where you carefully 'unwind' the lay of the cable and stretch it out into a cone shape. This helps the zinc to grab each strand as much as possible.  Secondly is the temp. of the pour. We shoot for 1080F which is hot enough to withstand being in the ladle for awhile as the pour progresses. The cable or strand is stripped with muriatic and force-dried with a weed-burner for a little bit of preheat. Be careful though because too much heat will anneal the wires. Any color in them and you're too hot.
Rinse water remaining in the strand can bubble out or worse. 

I used to be a little skeptical of the process because it DOES seem too easy. There's a photo here http://www.ballardforge.com/images/socket.jpg<http://www.ballardforge.com/images/socket.jpg> of one that didn't pass- a first timer's try. The pour was fine but the cable behind the socket was not 'seized' tightly enough with baling wire and it had unwound a bit before the pour. Looking at the cable, you would see daylight between the strands. What this'll do is distribute stress unevenly on each strand. Some are loose, some tight, etc.
Having done it now for a few years it's automatic and pretty impressive when you just finish one and then hang 20,000 lbs on it.

Steve
Seattle