Wednesday, February 11, 2015

Bach Steel (small business report)

This week's small business report is on Bach Steel, a small, specialty steel company in Holt, Michigan.  Bach Steel (517-455-4443) was started in 1997 by Nels Raynor after working several years as a steelworker.  Nels knew he was a "hands" guy from a young age because he would spend his entire weekend helping his dad in the ceramics studio.

Due to customer demand, Bach Steel now specializes in the restoration and moving of historic steel bridges and ornamental, wrought iron work.

Ornamental work

A closer look at the detail

Ornamental work is not the largest part of Bach Steel's operation but it has to be one of the most satisfying.

Steel table made with copper rivets.  How do you say Steam-punk cool?

Damascus hearts, just in time for Valentine's day.

Bridge work

Nels will tell you that Bach Steel does restoration.  Their restoration work does not change the visual impact of the bridge in any significant way.  There will not be a bunch of welded on, historically incorrect cross bracing.  But the bridges will be safer and, in many cases, moved to new locations and "repurposed".

Nearly all of these photos are from the Bach Steel website, with Nels Raynor's permission.

This photo came from a gallery that has many pictures of the rigging used to move bridges.

This is not an office job.  Picture from this gallery.  This bridge is in Portland, Michigan.
Eyebars are one of the most critical components of "structurally determinant" truss bridges.  The lower ends tend to have more corrosion due to poultice accumulation and they stay wet longer.  This end has been bead blasted and rough ground to open up areas of crevice corrosion.  This will be filled with weld metal and ground flush.
Different part, same bridge showing how weld metal is used to build the section back up.  This picture and the picture shown above are from this gallery.
Sometimes the eyebars are too far gone to save.  No problem.  He will just forge new ones.  This is from a bridge that was restored in Robertson County, Texas.  Gallery here.
Bach Steel does penetrant testing for cracks.  Most of the bridges he restores were built between 1870 and 1900.  They used hand forged, wrought iron eyebars.  Those weld seams show up as a crack on ultra sound testing or magnafluxing because of the silicon inclusions in the joint. It takes experience to know if an anomaly is a fatigue crack or an artifact of the production technology.

Mr Raynor estimates that restoring a bridge adds another 50 years to the bridge's functional life.  There nothing wrong with the design of these bridges.  After all, the youngest bridges Bach Steel restores are 115 years old.  All they need is some tender, loving care.

One point that Mr Raynor is passionate about is the use of wrought iron in some of the critical applications.  Wrought iron is very high in elemental silicon.  Modern steels use oxygen to burn off the carbon and silicon...then alloying agents are added back in.  With the exception of a few grades of tool steel (O6 and S5, for example) modern steels have very little silicon in them.

Silicon modifies the oxide coating on the steel.  The oxide does not become rust, but rather, clings to the base metal in a dense coating that resists further corrosion and pitting.  In a sense, wrought iron is a dark form of stainless steel.

As a steelworker who specializes in historic bridge restoration, he is very conscious of just how good wrought iron is for exposed, structural applications.  115 years of corrosion leaves a mark.  You can see what lasts and what does not.  He also knows that there are not that may people out there who are comfortable working with wrought iron or have the expertise to hand-forge custom hardware.

A critical part of bridge restoration involves rebuilding the roller nest.  A hundred foot span of bridge will change in length by 1.5" between winter and summer.  Depending on the arch of the road, loads can also cause the length of the bridge to change.  Note that this shoe and roller nest were constructed with vintage correct hot rivets.  Photo from this gallery.
The other end of the bridge rests on something that looks like this.  Note, this photo is not from Bach Steel.

Bridge Reuse

The greenest way to recycle something is to reuse it in its original application with minimal "reprocessing".  There are many, perhaps hundreds, of historic bridges that are available for repurposing.  In some cases they were too narrow to meet increasing traffic.  In others, there were concerns about the pounding they would receive from commercial trucking.  They are still more than sufficient for pedestrian, passenger vehicle and light truck use.

WAY cooler than pink flamingos!  Yes.  You could have one of these in your yard.

Bach Steel (517-455-4443) provides an excellent essay HERE on how to get your very own historic bridge.

If the science of structural failures interests the reader, Why Buildings Fall Down: How Structures Fail is a very good read of real-life failures in the field.

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  1. Nice report, and I had no idea there were folks that actually restored old bridges! Neat wrought iron work too!

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