Failure analysis done right!
Overspray Identification and Analysis
Determining if overspray
matches a specific painting project
requires proper collection, analysis,
identification, and comparison of the overspray droplets to potential sources.
Over the years, Geoff
Byrnes has developed and perfected
micro-analytical techniques for overspray identification and analysis,
sometimes even when the individual overspray droplets cannot be seen
with the naked eye. He has successfully carried out thousands
identifications on behalf of applicators, property owners, attorneys
and insurance companies.
The basic technique
The analytical procedure
normally consists separating
out the overspray droplets and potential source
each in potassium bromide, and pressing the
resulting mixtures into a tiny transparent
pellets about the size of a pinhead in a special micropress.
The pellets are then subjected to Transmission Fourier Transform
Infra-Red Spectroscopy in a beam
condensing optical bench to create spectra which are then
analyzed. The information generated by this
analytical technique has been accepted as sound forensic evidence by
throughout the world.
What we need
What we need to perform the
analysis are samples of overspray
and the dried coating
from the project which is suspected to have caused the fallout.
How to collect overspray from a vehicle
You will need:
- a bottle of oil-free alcohol (either grain alcohol or
90% isopropyl alcohol
- cotton swabs
- clean, new, oil-free razor blades (washed
alcohol and dried before use)
- aluminum foil
- sticky tape
- a container
as a plastic tub used for photographic film)
- a pencil and paper
- If at all possible, run the oversprayed vehicle through a
car wash (without wax) first. Clean the sampling area of all
remaining road dirt, oil
and grease by thoroughly washing it using
cotton swabs and alcohol before allowing it to dry. This is important
for the most
accurate results and if the droplets clean off easily, the matter has
- Scrape the razor blade over the sampling area at a shallow
angle to pick up the paint particles on the edge of the blade. If this
done carefully it should not damage the vehicle's paint or
glass - but
you are doing so at your own risk! We recommend you obtain
from a glass or mirror surface.
- Take the razor blade with the coating particles stuck to
(that we will remove them under a microscope) and carefully wrap it in a
square of aluminum foil. Seal the foil with sticky tape being careful
the tape is only on the outside and does not contact the razor blade or
- Place the packaged blade in the tub together with a note
identifying the sample and seal the lid on the tub using the sticky tape.
How to collect paint from a potential overspray source
- When only one coating material is suspected to be involved
easily be sampled by cutting a piece of coating from the structure
using a sharp
Only a small chip of coating is needed; about the size of a quarter.
The coating chip should be wrapped in aluminum foil, placed in a
plastic tub or envelope, sealed, and identified.
The cost for this analysis
is per sample analyzed and includes both a final report and copies of
the FT-IR spectral plots.
G.B. Byrnes Consulting
· 3004 Teague
Rd Houston, TX 77080 · (713)460-4130 · Email
update & © July 2007