Which paint and glue to use for a golden walnut?

Question

My goal is to craft a "golden" walnut by painting two empty shell halves and then glue them together.

So, my requirements on the paint are:

• color will be golden if this matters
• should not smear off
• should not hide surface nuances
• somewhat water proof, but not expected to be put into water

Then, I'm going to glue the shell's halves together. The glue must be reliable and yet allow though to easily open the shell (one time is enough, but if you could stick the halves again, that would be awesome).

Answer 1

For “medium- to large-scale production” (e.g. making golden walnuts as tree ornaments), we’ve successfully used both golden craft paint and spray paint. Especially the latter is a bit messy, but retains the surface structure very well.

Glue the halves together (wood glue or standard white craft glue will do), sandwiching a ribbon loop as hanger in between. For the spray option, protect the ribbon with masking tape, loop the hangers over a kind of rod, lining the ornaments up with a bit of distance in between. Spray, either outside or with a large cardboard box put on end to catch the excess paint. Let dry while still hanging on the holder. Remove tape, done.

For a hanger-less version, push a toothpick in the part of the shell where there’s a little natural gap, stick the other end in a piece of styrofoam or similar.

Answer 2

Use gold coloured oil paint.

Apply with a small paintbrush, dilute with (a mixture of oil and) a solvent like turpentine to increase the paint's thinness, so it will more easily crawl into the crevices and other details of the walnut.

Depending on the kind the glue might solve the paint a little, so just apply it carefully with a brush.

Once dried, it should be able to withstand water.
As an alternative you can use acrylic paint, but that's both thicker (resulting in a greater loss of detail) and less resistant to water.

Simple wood glue would suffice for glueing the two parts together. I suggest glueing the walnut first before applying paint.

Answer 3

A slightly “fancier” version than paint is gold leaf. You could choose the genuine material (kind of pricey) or a gold-colored metal. Especially the latter should be available in a good craft store, together with the adhesive and brushes to lift, apply and press into the small crevices of the walnut’s surface.

Depending on the chosen metal, a layer of sealant may be a good idea if you want to keep the nut for a while. And if you are actually going through the process (which is a bit more tedious than gold paint or spray), I suggest you consider the mini-hinge suggestion mentioned in a comment.