Pliage revisited.

Craig Bumgarner

Bohemian,

Wood, thin wood at least, bends much more easily parallel with the grain (from one side of the guitar to the other) than across the grain (from head to tail of the guitar body). So a guitar top can easily cold bent from side to side over curved ladder braces. If the top is to be arched only from side to side, then the pliage is not needed, but the sides in the tail area will have to be brought up higher to match the cylinder shape defined by the arches, as was done in some of the Dimauro chorus models.

If the sides are cut straight, as is more common and the top is arched from side to side, there will be a significant gap between the top and the sides at the tail block (~10mm). If the top is forced down to the tailblock, the substantial stiffness of the long grain will overcome the arch in the braces and much of the arch will be lost. If the braces are made substantial enough to accept this without losing shape, they will be over built and too stiff for good top response to the strings.

The pliage is one solution to this. Using heat to overcome the long grain stiffness, a bend is set into the top permanently at the bridge area so the gap at the tail is made up when the top is bent over the braces. You can simulate these effects with a piece of cardboard to help visualize.

The pliage is not a end in of itself, it is simply a means of producing a dome. When domes are built into most other styles of guitars, the dome is usually slight and the long grain stiffness is not critical. Also, the tops are usually fairly thin, so the combination allows the dome to formed in both directions by cold bending over the braces to the sides. By comparison, the dome in Manouche guitars can be quite substantial. The tops are often thicker and for the aforementioned reasons, the top will not bend to the sides n the long dimension, so the permanent fold (pliage) is needed.

As Al says, the dome can allow the guitar to be more response, louder and have a faster attack, because if taken full advantage of, the dome yields a lighter top assembly that is more quickly and dynamically set in motion by string vibrations. The dome is really something for nothing weight wise and much of what we think of as a good guitar is tied up in that old stiffness to weight ratio thing.

Bohemian

Thanks Craig.

Jazzaferri

I wonder if Ideally one would look for a flèche that had the bend one wanted in its natural state. Very hard to find though.

Bohemian

As in a bent limb/trunk ?

bill raymond

This whole pliage thing has been the subject of much speculation. Though I've never seen one so cannot verify it, but I understand that the Ibanez Maccaferri model, built to Maestro Maccaferri's specifications had a true cranked top, i.e. the sides were trimmed to support a pliage across the width of the top. This suggests to me that perhaps this was Maccaferri's intention all along, but that he was unable to get the Selmer crew to do this correctly, and settled for the configuration that Craig has explained above. We do know that he wanted to form his laminated backs with the dome built in, but settled for flat laminated backs that were domed by means of arched braces, so we can extrapolate that he may have accepted other compromises. My friend. Peter Davies in Wales had some email correspondence with Francois Charle concerning the pliage: M. Charle stated that the tops were scored with a knife and bent over a hot pipe, but I've never seen any indication that the Selmer production scored the tops. Again, we might speculate that perhaps Maccaferri did so on his prototypes, and maybe it was even done on some of the earlier Selmer production, but was abandoned somewhere along the line. Who knows. There's much we just don't know, and will possibly never be able to determine unless a long-lost diary in Maccaferri's hand should be discovered that more fully explains his thinking.

Al Watsky

You see the top scoring often on mandolins.
It would not be necessary to actually cut across the grain. You could just compress the fiber with a round tipped iron rod and achieve the same results as cutting, so there need not be much to see after the fact.