Woodworking Project Diary

[Sean M]

Applied a second coat of 15 g hide glue and 125 mL water (1:8) to the front of the shield. Cut out a batch of small practice panels 10 × 15 cm from leftover basswood shield planks to use for small projects. I can coat them with hide glue ("size") and gesso when I coat the front of the shield. Applying a coat of glue takes about 30 or 40 minutes including the time to heat the glue and the time to set up the workspace and tools, and the actual time holding a brush is a small part of that.

One has writing in black India ink to test a method of hidden writing in Aeneas Tacticus' treatise on how to defend a city.

Regarding 'how smooth should the panel be?' Laura Broecke has heard of panels which were scratched before the glue was applied to help the canvas and gesso stick, like the books on pavises say that pavises often have cross-cross cuts in the surface of the wood. A lot of ways we approach things, like aiming for right angles or getting wood silky smooth, were not necessarily how craft workers before the 19th century approached them.

[Sean M]

This week I applied the third coat of size to the back of the shield, the first coat of weak size to the front, and the linen to the back. I ripped a square of thin linen 50 by 50 cm, heated up the hide-glue-and-water to 65 °C (as hot as I could get it since the kitchen was occupied and I was working outdoors with just a kettle and two pots with a lid), soaked the linen in the hot size, lifted it out of the glue pot and let it drain, then spread it over the shield and pressed it with my palms to remove creases and high spots just like Cennino says. He says to let the linen dry for two days.

Gave the small panels their first coat of strong size with the leftovers from the size for the linen. Let the solution cool and put it away in a refrigerator.

Notes

Cennino used strips of linen. That could be a good option for covering a large shield. Some sources tell me that when pavises have a rawhide cover, any patching in that cover is usually reinforced with stitches, but those pavises were made by barbarians beyond the Alps.

An advantage of hide glue is that its not an alkali like cheese glue and its easy to remove from skin and clothing with warm water. Cheese glue has the noxious lime and its hard to clean up once it sets. Putting in the linen probably cooled the hide-glue-and-water mix, I could have let it soak longer but it seemed to work.

I got some thick brown sludge in the bottom of the glue pot. That could well be from letting the boiling water in the bottom pot touch the bottom of the glue pot. If I had a fire (or an electric hot plate) it would be easier to boil the bottom and use its steam to heat the top. This batch of size started out as 30 g hide glue and 300 g water but after removing the sludge and adding back in some more hide glue powder it may have ended up a bit weaker.

Covering a double boiler with a lid when I am not measuring the temperature or brushing the glue seems to help the top part heat up quicker.

[Sean M]

Trimmed the linen to shape. Applied a coat of strong size to the front of the shield, and used the chance to stick the linen from the back to the front of the shield where it folds over the edge.

Because the rim is wide and flat, leaving the wet linen on watertight surfaces like plastic lets wet glue build up on the bottom of the shield. Resting it on parchment paper or a few thin dowels gives air flow and might stop the glue from pooling.