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Pre-bending Herringbone Purfling

Pre-bending Herringbone Purfling

by John Calkin

Published online by Guild of American Luthiers, June 2021


Herringbone purfling s a lot easier to work with if it is prebent before it is glued onto the guitar. This is best done after wetting it first. I always use a brush to spread glue on guitars. I keep a coffee cup of water handy at all times, along with an acid brush with the bristles properly trimmed back to the stiffness I like. I dip the brush, then hold it stationary as the strip of purfling is pulled across the cup underneath it. Soak the purfling well on both sides. This should take only seconds. Then the strip is pulled through a dry cloth. Soaking it for too long will encourage it to come apart as it is bent. Give the purfling a minute to absorb the water, then tape the butt end into the channel it will be glued in later. Wrap it carefully around the lower bout using a couple pieces of masking tape to hold it tight. More tape, as well as care, will be necessary to make it conform to the waist area. The wrap around the upper bout should be as easy as the lower bout. In the photo, you can see how much tape was used as well as the small fan used to dry the purfling before gluing it in place.

All photos by John Calkin

Herringbone will wrap around a moderate Venetian cutaway but do it gently and by stages. To be safe, the purfling can be wet and then sliced lengthwise on one of the glue joints using a single-edge razor blade.

On a tight Venetian cutaway, the purfling must be sliced. On this tight-waisted jumbo guitar, the purfling was sliced from the top end to below the waist area to help coax this half-herringbone purfling to conform to the shape of the guitar. Sliced purfling doesn't need to be prebent but you might wish to wet it as you reach that portion of the install. Slicing the purfling can go awry and destroy it. Buy extra. ◆