Acoustic Guitar Build – Day Three

Top Soundboard

Mark the centre of the soundhole and then from there, where the soundhole intersects the centreline at top and bottom.

Mark also where the inner and outer edges of the rosette will intersect the centreline, top and bottom, the inner will be somewhere between 1/8″ and 3/16″ from the edge of the soundhole.

Drill centre of soundhole to take the pin for the router circle base. With the ping inserted into a piece of MDF, mount the soundboard on top and we can start routing.

Make a score cut (1/2mm deep through at roughly the middle of where the rosette will be – by trying a piece from the rosette we can see if we need to make the radius longer or shorter by looking whether the corners or the middle touches the score cut.

A black-white-black binding will also be inserted either side of the rosette – once the wood pieces are fitting, rout for the outside binding first, then the inside – aim for a sliding fit with both bindings and wood pieces. Rout to just over half of the thickness of the top.

Note: The top should be 2.5 – 3.2 mm thick. Cedar is softer so you should aim for the full 3.2mm but spruce is stiffer and can therefore be somewhat less.

Once the routing is finished, paint * white glue* in the rout, not forgetting the sides – white glue does not set as fast as the yellow titebond.

Place the first wooden piece inside then insert the inner binding; start and finish at the top where the fretboard will cover. Next insert the outer binding and when all is in place, feed in the other pieces of wood. Once happy, place a board over the top and clamp.

Sides

Put together and plane one edge straight and then, using the straight edge against the bandsaw fence, cut the sides to be 100mm or 4″ wide lengthways.

Using the mould as a guide, mark the start, apex and finish of the first bend. Heat the iron and spray both sides with water. Bend around the iron  and test often against mould: when removing the wood from the mould, keep the tension in it otherwise it will just straighten out again.

Once it roughly fits in the mould, clamp it in and let it sit until it cools and dries. Repeat for the other side; if there are tight corners (cutaways) then once it fits roughly in the mould, you can clamp it in, spray it and take it back to the iron and work it tighter into the mould.

Bend the lining to shape – the rounded side goes towards the bottom of the guitar and the kerfed side is stuck to the sides. For tight corners where the kerfed edges need to be closed over and they don’t fit tightly, cut wider kerfs with the bandsaw. Clamp in place and once happy, glue and clamp all round leaving 1 – 2mm overhang.

When unclamping the lining after the glue had dried, I noticed that the lining inside the horn on my cutaway bend wasn’t stuck properly to the side. In order to remedy this (and it *does* need to be remedied), cut the side of the loose lining piece so that we can press it against the side, introduce more glue and clamp it back up again

Fretboard

Thickness to around 6.5mm, draw a centreline and place 5 bits of double-sided tape on the back.

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