Answer a Question with a Question: Slurry Testing Frequency
I am frequently asked how often should I test my slurry? I know you shouldn’t answer a question with a question, but what about a series of questions? ✓ How often do you have to make adjustments to your slurry? ✓ Are the adjustments with water, binder or a mixture of...
Hitting the pH Target
Stability of colloidal silica is important for the health and performance of an investment casting slurry. pH is one indicator as to the stability. Conductivity is another important indicator and information on that topic can be found here. Accurate measurement of...
Clean Calibration: Maximizing Slurry Test Results
One of the most common slurry tests performed for investment casting slurries is SiO2 percentage. Insufficient concentration of SiO2 in the slurry creates a weak shell. However, having too high a concentration can also cause a weak shell while potentially gelling...
Data Collection and Slurry Control
I had a wise customer comment to me once that he didn’t mind collecting data as long as the operators/engineers were going use it for slurry control. I completely agree with that statement but would add: make sure the data you are gathering is meaningful. So, what...
A Balancing Act: Managing Slurry Conductivity
Last week, we discussed conductivity and how high levels can contribute to reduced slurry health. Now, we will discuss potential causes and what can be done about it. Some common causes of high conductivity are: ♣ Increase in the number and strength of ions ♣...
Why Layering can be Beneficial: Conductivity and Slurry Stability
“How do I know when my slurry is going bad?” I have heard that question many times and I imagine standing over the slurry tank admonishing it by saying, “Bad Slurry! Bad Slurry!” But, let’s put humor aside, take a step back and understand the parameters that impact...
Shark Teeth or Iowa Cornfield? Slurry Control Chart Tips
If your slurry control charts look more like shark teeth than an Iowa cornfield, perhaps you have some opportunity to control your process better. If you don’t have slurry control charts, do you know what is happening in your slurry over time? Charting your key...