WtEM Archives ⋆ Twisted Dreams

Final Passivation

Yesterday finished assembly and this morning was the final passivation.

Early in the process we do a hard passivation with Nitric Acid, but at this point it is a special Citric acid solution that cleans and passivates.

Because it is a much less acidic solution, this one can be applied with a squirt bottle, and it tends to cling and stick to the metal.

We let it sit and do its chemical magic with the Stainless Steel, and then Rinse like crazy. After a few trials, we figured out that a regular garden hose just did not give the rinse we wanted without taking a very long time, so the last few have been power washes like the one this morning.

How hard is 316 Stainless Steel?

During Pinning day Yesterday, Dave completely burned through 3 bits in about 20 minutes. Just a little bit dense…

Power Tools… FTW

The base of When the Earth Moves is the Point where the largest base gear is erupting from the earth, so a smooth finish made no sense…. but the Hammered Stainless Steel looks man made and manipulated. We wanted something more natural and yet cracked looking.

After some experimentation on scrap pieces, David discovered that his air hammer made an excellent “crinkle” finish, so we are adopting that for the base.

It is much faster than hand hammering, but LOUD. Turn your volume on before hitting play…

Raising up Gears 3 and 4

The other day we reached the point where 2 more gears got mounted onto the statue. With the gantry crane and a helping hand from a friend, it went like clockwork, and was one of the easiest things we have done in the project thus far.

If I had a hammer……

We have talked a lot about “shiny” in these posts, but that is not the only finish for Stainless Steel. On When The Earth Moves, the base and uprights are going to be forms of Hammered Stainless.

How do you get Hammered Stainless?

This is a fun part,( although kind of back breaking) and I even got to get in on some of the action:

An Evening Glow

The protective layer on Stainless Steel comes not just from lots of polishing, but also from an acid treatment ( Nitric Acid in our case) and then a following with a citric solution. It has been so incredibly hot outside that in order to keep the acid effective, Dave has had to spritz it down with a little water occaisionally before finally washing it off. This treatment is what creates the hard chromium layer on the Stainless Steel and helps to prevent corrosion.

it is a citric solution that the statue should be washed down with once a year to remove any residual crud that might build up from sticky hands and whatever is in the water evaporating off.

All of this is well worth the effort, in the evening light you can really see the reflective glow of the shiny surfaces contrasting with the shadows.

Assembly and test

As the finish process on the Gears starts to come to a close, the structural work begins.

The first First step is getting the uprights in place and a small gear topped on…

Once you have that, what else could you expect to happen?

The Path to Shiny

Almost everyone has a mental image of Stainless Steel as smooth and almost reflectively shiny. However, it does not start life that way. There are many potential paths to shiny, and this week was dedicated to mapping it out for When The Earth Moves. To get the finishes we want, (they will be different for the gears and the fixtures ), and there will be a variety of steps from acid treatments, disc grinding, die grinding and orbital sanders. The sanding will range from 80 grit to 120.

Why so much work? Besides the fact that the steel comes in fairly “crusty”, the water jet leaves marks as it cuts as well. This is a gear tooth as it comes from the cutter. Note all of the horizontal gauging and scratches in the steel from the cuts. This is not at all the look and feel of the gear that we want, so the surface has to be finished to get the right effect.

You can see the difference when you look at another tooth on the same gear, after acid, disc grinding and lots of sanding at various grits- this is the shiny smooth finish that is the goal. At about 20 minutes ( for the edges, not the faces) per tooth, and 94 teeth in the statue, plus faces, spokes and cutouts, you can understand why we often say that Art is a Labor of Love.

Prepping the glass molds

It is time for the project to take on parallel paths.

While Stephen’s Machine shop starts to weld the base, we get to start working with Kokomo Opalescent Glass to get the glass inserts poured. We had the molds cut in the extra space of the steel plates to save time and money, but this meant that Dave had to attach some sort of lift handle on them so that the glass folks can handle them.

For now, welding for us means a trip up to Dave’s folks’ farm and using his dad’s shop. We picked up the parts and supplies we needed to be working with Stainless Steel ( not the normal welding material on a farm),and headed north.
For Dave, working in his dad’s shop is like tapping directly back into a long family history.

This is the shop he has welded in for decades, and there are metal clamps he works with when welding here that are older than he is.

The goal for the day was to makeshift lift hooks that KOG would be able to use to move the one inch thick stainless molds around. There are two molds- the bat for the bottom gear and the crescent moon shape that is in the top gear. Dave ended up bending some stainless screw hooks and welding them onto the tops of the molds to make a lift system that can easily have a rod inserted through.

Getting the alignment perfect so that a metal rod can be inserted means careful measurements and lots of clamps to hold things in place until they get tacked down by the first welds.

Watching him work this weekend reminded me that it is true- you really never can have too many clamps in the shop.

Site Survey….

SiteMeasurements Today became the start of a huge adventure for the Cogbots crew. We have been granted the commission to make the new fountain statue for City Hall in the City of Kokomo, and it was time for a site survey. A bit of measuring, and lots of hands and eyeballs on the site where a new stack of steel gears will be installed.

As you can see, the site has a slight gradient, so part of today’s mission was to measure the grade and come up with a plan for the best way to ensure that the statue will end up level despite the slight drop. If we did not properly level the base, the statue would end up leaning 4 inches out of kilter at the top of it’s 8 ft height.

We were also looking at the arrangement of the base to the building and to prospective light, since we want to get the stained glass effect from the Kokomo Opalescent Glass Inserts as much as possible.

An interesting lesson we learned with the Infernal Device installation is that any public art is just that– very public.

Today, even though all we did was step across the construction blockade, take some measurements and some pictures, we had our first visitor. Happily, he was excited about the project and is looking forward to coming back as we progress. We look forward to having him and anyone else local stopping by and chatting when you see us on site.