Gesso

I have known about gesso as it relates to gilding and how to expect it on antique furniture, but I had never gotten around to working with it nor discovering its potential. It represents one of those well established methods of woodworking that fell out of favor with the advent of industrialism and plastics, in particular. And as with so much of woodworking of old that has been experiencing a revival, I think gesso has potential to follow this trend.
Initially I was planning on following the method that Pfollansbee uses to attach hinge battens to a 6 board chest lid: clenched nails. I ended up having to use Scotch pine glulam for a lid, which made me reconsider whether clenched nails would be appropriate or effective. I thought first about countersinking the underside of the battens and attaching the lid with woodscrews. The thinness of the lid stock made me hesitate. I had finally found a source of hide glue in China and the idea of gesso as a filler seemed to arise sua sponte.

I had already marked off the spacing but had not predrilled the holes for clenched nails. I instead drilled the pilot holes for the screws and then countersunk for the screw heads below the lid surface. At this point I was committed to using gesso even though I had not quite figured out how to make it or what to expect from it. Online resources focus on gesso as sizing for preparing paint surfaces on wooden panels, which is a good start and better than nothing. I bought both plaster of Paris and chalk dust, but I have not yet experimented with the plaster of Paris. I also bought the chalk dust as an additive for milk paint, but I have not been using it for that.

There are some guidelines for determining the consistency of the chalk dust/ hide glue filler. The most useful one is to create a mixture that resembles light cream. My gesso ended up as a rather heavy cream but I applied it anyway.

applied to deep countersinks

At about the same time that I was struggling to complete the 6 board chest, I was building a Dutch tool chest. I had glued together some blocks that would be drilled through to accept grommet handles. Some short grain split out, yet rather than curse the arbor gods, I saw another opportunity to try out gesso as a filler.

second application

The tool chest bracket required two applications. Since gesso is a water based filler, as it dries, there is some unavoidable shrinkage. After letting the gesso dry sufficiently. I used a riffler to abrade the excess and then a card scraper. I am still not certain what the best way to bring down the excess gesso to form a flush surface. It can be moistened as I did on the 6 board chest lid to produce a smooth surface. The water also lifted the milk paint, which had to be reapplied anyway.

scraped gesso flush with surface

smoothed with hot water

Both of the surfaces were intended to be finished with milk paints. It might be that as the rise of the natural wood grain aesthetic rose, and the use of painted surfaces fell out of fashion, the use of gesso also dropped off. I was eager to see what the results would be after painting.

painted and oiled gesso infill

smoothed and overpainted

The gesso does not seemlessly fade into the wood surface, but I still like the results and am  further intrigued by what else can be done with it. I have not applied oil to the 6 board chest lid but the results of the linseed oil on the gesso in Dutch tool chest bracket show that the gesso accepts the oil well enough.
I think that adding some glycerin to the hide glue can enhance the elasticity of the gesso to account for seasonal expansion. It might be possible to texture the gesso to make it match the pattern of endgrain. I will also go lighter on the chalk dust in the next batch. It's clear from these two examples that gesso opens up possibilities that I had not considered previously. It complements the the use of milk paints wonderfully.