LesFlo wrote:
Baltic Birch with phenolic glue is extremely hard to check MC. As Dave Harrison mentioned above, the glue itself is conductive. In theory you have to use prongs and stick sideways into just one veneer layer, avoiding the prongs coming in contact with the phenolic glue.
The only way to truly test MC is with an oven test.
If you test such plywood with a meter (with or without prongs), you often will get readings from 14-20% MC. Take that same sample and do an oven test, and the result will usually be between 8-10% MC.
The phenolic glue requires the veneers to be something like 10% or 12% MC or lower when hot pressing the plywood, otherwise the glue will not cure. So unless finished plywood has been exposed to high humidity or soaked in water, it will not be the high MC reading you get with a meter.
Evidently the backing is Russian Birch with Phenolic glue
Baltic Birch with phenolic glue is extremely hard to check MC. As Dave Harrison mentioned above, the glue itself is conductive. In theory you have to use prongs and stick sideways into just one veneer layer, avoiding the prongs coming in contact with the phenolic glue.
The only way to truly test MC is with an oven test.
If you test such plywood with a meter (with or without prongs), you often will get readings from 14-20% MC. Take that same sample and do an oven test, and the result will usually be between 8-10% MC.
The phenolic glue requires the veneers to be something like 10% or 12% MC or lower when hot pressing the plywood, otherwise the glue will not cure. So unless finished plywood has been exposed to high humidity or soaked in water, it will not be the high MC reading you get with a meter.