Dry Chemistry Lab

James Guidry and Eric Broaddus are running a 3-point bend test on a sample using the Soiltest Versa Tester with Digital Load Cells.

James Guidry and Eric Broaddus are running a 3-point bend test on a sample using the Soiltest Versa Tester with Digital Load Cells.

This lab is also known as our sample preparation lab. It houses sample preparation equipment, chemical storage and testing equipment. We often grind or finish our stone samples using automated polishing equipment. Here in this lab we have the capability of testing the mechanical properties of our stones before and after stone strengthening is applied by using equipment like the Soiltest Versatester. Stone cleansing tests and conservation efforts are conducted here.

  • Keymaster Tracer V-III portable X-ray Fluorescence Analyzer – a handheld vacuum XRF multi-elemental analyzer with a solid-state detector, ideal for in-situ studies in the field.
  • Minolta Vivid 9i 3-D Laser Scanner — This equipment can be used for reverse engineering to reflect the shape and dimension data of mock-ups or prototypes in design drawings, or checking part shape, checking molds or inspecting quality in prototype-production or mass-production processes. With the additional 3D data integration tool, relatively large parts such as doors, bumpers and interior panels can be rapidly measured and the data merged with high accuracy.

Environmental Exposure Lab

Environmental Exposure Chamber

Environmental Exposure Chamber

NCPTT operates a one-of-a-kind custom exposure chamber to study the interaction between air pollution and cultural materials. The chamber was designed and built in 1987 by the National Park Services (NPS) in partnership with the National Oceanic and Atmosphere Administration (NOAA) and the U.S. Geological Survey (USGS.) It was moved to NCPTT from Virginia in 1996.

The chamber is one of only three of similar capabilities in the world. It is a re-circulating wind tunnel that allows precise control of temperature, humidity, wind speed, pollution concentration, and turbulence. Up to eight samples such as limestone and marble, can be exposed at a time. Samples are typically exposed for 10 days under conditions comparable to Philadelphia in the springtime.

Following exposure, the samples are then shaken in a hydrogen peroxide solution to convert the absorbed sulfur dioxide to sulfates in solution. The resulting washes are analyzed upstairs in the Wet Lab via Ion Chromatography.

Wet Chemistry Lab

The wet lab houses much of the facility’s analytical equipment. It is used to characterize samples such as limestone and marble before and after experiments.

  • QUV Weatherometer – known as an artificial weathering chamber This instrument artificially ages samples by exposing them to UV light as well as humidity and even water spray (represents rain.) For example, a stone can be studied before and after being treated with a stone strengthener. Then the stone can be weathered using the QUV. After about 800 hours, the treatments can be significantly deteriorated. By studying both treated and untreated samples we gain more insight into a treatment’s efficacy, especially in conjunction with the other analysis done here.Solarius Laser Profilometer – characterizes the surface morphology of a sample by using a laser reflected onto a surface of the sample. The principle is similar to the commercially-available; laser tape measure, only on a microscopic scale and scanned across the whole face of a sample.
  • FTIR (Fourier Transform Infrared Spectrometer) – uses absorbed light through infrared regions to observe the chemical makeup of a material. Depending upon the types of chemical bonds present, infrared light will be absorbed to differing degrees throughout the infrared spectrum.
  • Colorimeter – measures color and brightness according to a 3-dimensional color space with color and light coordinates. This provides numerical color change information.
  • Microscope – This device is used to examine samples. MZ8 Leico can magnify a sample up to 80x. The Micro Imaging video recorder is attached to the optical device of the microscope to capture images for computer analysis.
  • The lab needs high purity water, which is supplied by a reverse osmosis system in tandem with a four cartridge filtration system. We produce extremely purified water in-house.
  • The Ion Chromatograph allows us to measure ion concentrations in a solution. We commonly use it to determine the amount of pollution that is deposited on stone samples in the environmental exposure chamber downstairs.
  • KeyMaster Tracer V-III Portable X-Ray Fluorescence Analyzer
  • Thermo Orion pH/Conductivity Portable Multimeter.

National Center for Preservation Technology and Training
645 University Parkway
Natchitoches, LA 71457

Email: ncptt[at]nps.gov
Phone: (318) 356-7444
Fax: (318) 356-9119