After a too long hiatus the time has finally come to put TF1 to the test. Every good testing foot needs a good testing substance to be imprinted into. For the purpose of this and subsequent testing 25 pounds of volcanic ash were procured from Davens Pottery in Atlanta, GA.
After reading up on the MSDS for volcanic ash it was time to don the proper safety equipment.
Before jumping to the casting process I wanted to make a few test impressions. Using a small amount of the volcanic ash I filled a baking dish large enough to accept TF1. TF1 was impressed to a depth equal to the thickness of the foot.
(I hope that's not the good china)
After removing TF1 from the volcanic ash some pressure ridges could be seen extending out from the rim of the print and running horizontally along the inner print wall. A large fissure was also apparent that almost bisected the front of the ball just behind the toes. These are all classic signs of a ridged fake foot being imprinted into the ground.
With the fun over it was time to get down to business. Since the confines of the baking dish were limited (and the wife was frowning at me) I moved on to a larger box for the actual casting experiment.
After lining the box a sufficient amount of ash was added. In hindsight I used way too much but this is a learning process. With the ash added there was nothing left to do put press TF1 into the volcanic ash.
Prior to moving on to the casting process the temperatures of the water (57 degrees F), ash (67 degress F), and plaster (67 degrees F) were noted. The room temperature was 71 degrees F and the relative humidity was 38 percent.
With a proper print to cast and the temperatures taken it was time to prepare the plaster of paris (PoP). The manufacturer's suggested mixing ration was listed as 2 parts plaster to 1 part water. Accordingly 800ml of plaster were added to 400ml of water. The plaster was mixed into the water by hand. As soon as the slurry was properly mixed it was poured directly into the center of the print at a height of approximately 3.5" and at a pour rate of 100ml per second.
The slurry was given one hour to harden. During that time an interesting effect was observed. The ash in immediate contact with the slurry had begun to loosely bind to the slurry, leaving a distinct gap from the rest of the ash that completely surrounded the print.
As mentioned after one hour the cast was lifted from the print. A large quantity of the ash lifted out of the box along with the cast. Given the binding action observed along the edges of the print this came as no surprise. The cast was given 24 hours to fully harden before being cleaned.
Once fully dried all ash was removed from the cast. It came as no surprise that the cleaned cast exhibited a wide array and variety of casting artifacts. The first two photos are of the cast before all ash was removed.
The circle in the above photo (and observed in other photos) is the point where the slurry was poured into the print.
That's my story and I'm sticking to it. Given that these casting artifacts (and their similarity to alleged "dermal ridges") was anticipated the results came as no surprise. With a suitable control cast established I hope in subsequent testing to remove temperature and mixing variables as possible causes.
