Texture and Patina

One thing said about craft masters is that they are in control of their tools and techniques. That is what skill is all about. But when it comes to the issue of surface patinas watch out.

Early on in my metalworking experience I was visiting with an artist who said he never agreed to create an exact color surface for a client even if they had the target example in hand. Under no circumstance would he accept an color image. At the time I didn’t think much about it but it wasn’t long before the complicated relationship between the alloy, the surface texture and the finish chemicals sunk in.

My first work taught me something about the differences which can result from fire scale effect differences between the coal forge and the gas forge. The “tooth” and gross texture differences between hot wire brushing, pickling, planishing, sanding and tumbling are remarkable.

One of my first really difficult struggles came when working with a sheet of hot rolled A36. Apparently the alloy differences in the surface made it almost impossible to get an even color with hot waxing. I think that may have been when I started experimenting with spraying Minwax polyurethane instead of rubbing with the paste wax.

More recently I have seen a similar problem with creating a rust patina with hydrochloric acid and hydrogen peroxide on A36. If the pieces are from two different batches of A36 the problem is magnified.

The chandelier and pendant images illustrate the color variation due to (in addition to the camera) the different metal stock alloys in the tube, sheet, flat bar, balls and chain, and the surface texture differences between the glass sockets and the smoother tube.

Now that I am aware of some of the potential bummers I have somewhat more control of the process but, really, I don’t mind the help of some serendipity.

http://www.persimmonforge.com/

Wheatscapes

I just finished an interesting project. A new client from Nebraska requested several small wheat sculptures which would be presented as acknowledgments of service in a wheat oriented business. Wheat is a popular icon in the plains states so I welcomed this an an opportunity to experiment with some ways I might present the motif in my display in the Prairie PastTimes gallery.

Initially six pieces would be required but over the next month the number grew to nine. I worked with several concepts and had about twenty renditions which could be completed by the deadline but decided to focus on a rectangular frame style to insure the group had some common denominator.

It has been a half century since I participated in a grain harvest although I have followed agricultural issues at least as closely as I have followed sports over the years. Wheat harvest in Kansas is a big deal.

As I laid out these pieces a lot of sketchy images appeared to me which included sun, heat, dust, waving golden grain from horizon to horizon, sky nearly as wide and stubble clothed earth exposed as the grain is swept away.

There is also the machinery, new ones, rusty ones and rusty welded ones. There is a lot more, the urgency, the anxiety, the fatigue, the noise and the satisfaction which I am completely incapable of illustrating in my ironwork.

I’m generally satisfied with the experiment from my perspective. We’ll seen in a week how they were received.

http://www.persimmonforge.com/

Creating a Rust Patina

A sealed rust patina, I find very appealing and it can be especially useful in outdoor applications. I plan to use it on the outdoor sunflower sculpture on which I am currently working.

In this project I have used the usual 14 gauge material to built the hollow formed stem components but they are not yet fully assembled. Up to this point the pieces are less than 5' in length, which is the maximum my tumbler will accommodate.

I decided to go ahead and start the rust patina process and let it work as I studied how to complete the project and to store all the pieces outside which gives me that much more shop working space and lets the weathering work on the patina naturally.

The surface was cleaned with a degreaser such as acetone or lacquer thinner after tumbling. Then I applied muriatic acid (hydrochloric acid) with a chip brush and immediately sprayed the surface with hydrogen peroxide in a plastic spray bottle.

This will usually produce some rust color almost immediately. I'll return to check on the progress every few minutes and probably brush with the acid another time or two over a half hour period. By then the surface usually looks pretty evenly rusted and after that I use only the peroxide spray another couple of times. I leave the pieces outside to weather until they are ready for final assembly.

The last step will be to apply a sealer when the project is finished and the patina is evenly established. I will use fast drying satin polyurethane as the base coat. Several additional coats of the same can be applied or another type of satin sealer which is compatible with it. I have experimented with several finish combinations to find what works for me and what doesn't.

http://www.persimmonforge.com/