Veneer Splicer Problems 6: Blue Staining

Troubleshooting checklist for dealing with staining that occurs during veneer splicing operations. January 4, 2007

Reprinted with permission from Diehl Machines,

Veneer Blue Staining

Metallic stain marks on either side of the glue line caused by condensation and moisture. More common on high humidity days. Generally exist in coarse grained oak.

On veneer already stained, the ink can be removed by applying a 10% oxalic solution to the stain.

Moisture content of veneer is too high.

Dry veneer to lower moisture content. Store in humidity controlled area.

Glue is wet when veneer is spliced.

Allow the glue to dry completely before splicing.

Humidity in area is high.

Reduce the temperature setting as much as possible and increase the feed rate.

Install a compressed air jet blowing on each pressure chain in the pressure bar.

Install a hot air gun in the center hole in top of the pressure bar.

Install chrome plated chains.

See other articles in this series at:
Burning, Burnishing, Crimping
Marking of Stock, Grooving Along the Glue Line, Incomplete Glue Joint
Poor Jointing, Excessive Glue Spread, Crimping

Reprinted with permission from Diehl Machines,