When diagnosing a problem you have to consider the complete finishing system, so here are a few of the questions
that you should seek answers for:
- Did this project involve any new products or techniques
- Did the problem appear right away or after a period of time
- Did the problem appear over all of the surfaces, or was it localized to particular areas like edges
- What substrate was the finish applied to. Is this a substrate normally used
- What is the moisture content of the wood
- Was the wood acclimated to the shops temperature and humidity conditions, or was it recently acquired.
- Observe wood storage area and measure area temperature and moisture content of a few pieces. Spray the material
out on a piece of glass to eliminate any possibility of substrate interaction with the coating.
- What type of abrasive was the wood sanded with and with what grits
- How soon after sanding was the wood stained or sealed
- Observe sanding operations and operators techniques. You also want to insure that grits are not being skipped or
that the abrasives are not being used after they are worn causing burnishing to the surface.
- List all components and their manufacturers
- What was the sequence in which they were applied.
- Dry times between each component application
- How many coats of each component were applied
- What was the wet mil thickness of each coat
- Total system dry mil thickness
- If necessary, was the finish properly catalyzed
- Was the finish reduced. If so how much and with what reducer
- Observe finishing operation and finishers. Measure wet mils of a finish application. Watch finishers technique. Is the
spray area well lit, clean and organized.
- What day was the finish applied
- What was the temperature and humidity when the finish was sprayed
- What thinners were used and how much
- Was the material temperature and viscosity checked
- Observe where material is stored. Check temperature of stored finish. In the winter does the thermostat get turned
down nights and weekends. How is make-up air obtained. Check spray area for drafts.
- What type of spraygun was the material applied with
- Did the equipment have the correct nozzle, needle and air cap size for the material being applied
- If a pressure feed or air assisted airless system, what were the pressure settings
- Observe a momentary burst of material being sprayed onto a piece of paper to see spray pattern and atomization.
Sometimes what people say and what they do can be two different things, so observe and listen are the first keys to
diagnosing a problem.