Thursday, April 25, 2013

1/12 Scale Classical Guitar Case

One case was not enough, but two of the same would not do. I measured one of my classical cases and went to work.

The cases begin with an outline on graph paper. The cases are made from 1/4" foam core board, with as many cardboard shim pieces needed to get to scale thickness. This stack is glued together and weighted til dry. The outline sheet is pasted on the top and a rough case sawed out with a jewelers saw, then refined on a sanding drum in the Dremel. Final shaping done with hand sanding sticks.

Once shaped, black construction paper with an outline about 1/8 inch additional size is glued to one side, notched, glue applied then folded over with plastic wrap which is pulled taut and held til dry. This step is then repeated for the other side. For further even pressure I used wide rubber bands rounded over the edges. The side of the case then gets a piece of paper as a spacer to bring the inner surface up to the level of the folded edges. Once this is dry the final edge piece of paper is glued in place and rubber banded til dry.

At this point in the Jumbo build the case got two coats of a fine texture black spray which was lightly sanded between coats and after final coat leaving the pebbly surface found on full size cases.

There are a few photos of the classical next to the Jumbo case for comparison.

I compared the Jumbo case against my full size cases and noticed that there is one more detail common to all of them that was glaringly missing from the models. White stitching on the lid edge attaching the lid lip to the lid. Hmmmm.... Several attempts were made to create the dots by hand with a teensy brush.... on painted scrap paper. The results were less than convincing.

One of the tools I got at this estate sale I went to earlier this year was a set of pounce wheels. These are used to make rivet lines, perforate paper, trace pattern lines with carbon paper etc.
I tried several ways to paint a very thin white line on a strip wide enough for the lid rim, and eventually settled on blue tape. This gave the line I wanted, and then a plastic guide was made wide enough for the ponce wheel which poked holes in the white line and created fairly convincing stitching.

I glued a strip to the Jumbo case, and added one to the Classical case as it was being completed.

There is a series of pix showing how I made the hardware from thin sheet brass and brass wire. The handles are made from aluminum tubing, coated in vinyl and hinged to the cases. I added a latch on the far side of the Jumbo neck area, and replaced the lock with one with a "button" to open it with.... if it really opened.

I also have bluegrass and long neck banjo cases started, and the finished items will be documented in a later post.

That is it for tonite,

Stay tuned...

Foam board with cardboard shims as needed.
As you can tell, this is recycled foam board, and "No Wrinkle Glue".

Glued stack.

Outline glued on with paste for easy removal later on.

Rough cut to outline.

Sanding to outline on homemade Dremel router base

After final hand sanding.

Side cover glued on.

Clamped for drying.

Trimmed and notched for folding.

Gluing edge flaps down.

Pulling snug for drying.

Other side glued and trimmed.

Drying after notching and gluing.

Center filler strip to level for side strip.
Other side of filler strip.
Rubber bands overlapping edges and cinched in.

Gluing on case side strip.

Case cover glued.

A little overkill on rubber banding for drying.

Classical case prior to paint next to Jumbo case for comparison.

Classical case prior to paint next to Jumbo case for comparison.

Classical case prior to paint next to Jumbo case for comparison.

This is a strip of construction paper trimmed to width, then given two coats of fine texture black paint,  taped and painted.

Masking removed.

The strip is taped down, and the plastic guide taped in place with painted line showing.  Next the line is "stitched" in with pounce wheel.


Edge glued to  case lid, handle installed

1/16" tubing shaped for handle.

Flattened ends.

Drilled for hinge pin.

Handle coated in vinyl handle dip.

After dry, the ends are trimmed, filed thinner and rounded off.  The hinge pin is a loop of brass wire with a piece of 0.002" brass shim stock at the base.  See the completed pix.

Latch blanks in 0.020 sheet brass.

Ink dots for denting.

Folded over, trimmed and filed.

This is the clearest shot of the handle hinge installation.

Latch bail wire formed.

Ensuring snug fit.  Bends need to be at narrowing of back plate.
Lock "button formed with center punch.

Lock tongue folded over after trimming and filing.

Latch glued to case, and held with the wire bail.

Handle, lock and top latch installed.