Wooden Board Infilling pt. 2

So, I’ve found some spare wooden boards in the studio that have perfect woodworm holes to practice on.

I’ve also spoken with the Objects Conservator at The Royal Cornwall Institute – Laura Radcliffe about how best to go about the infills, she’s given me some good pointers, and I’ve followed her instructions with some changes or tweaks…

Area #1 to be filled. Before treatment.

Area #2 to be filled. Before treatment.

First of all, I’ve primed the area to be filled with the 10% Paraloid solution, by flooding the tunnels and holes, making sure all the walls are covered to prevent any of the infills seeping into the surrounding wood. I did this twice, just to make sure.

Area #1 with 1 coat of 10% Paraloid.

Area #1 with 2 coats of Paraloid.

Notice that it really discolours any leather that it comes into contact with.

Area #2 with 2 layers of 10% Paraloid.

I then made up a mixture of the micro balloons, with two drops of burnt umber acrylic ink (Daler Rowney). At this point it’s like flour, and adding the paint doesn’t seem to do anything – you can’t mix it up.

Using small metal pots (or glass or ceramic, but not plastic) pour out a little of the 40% Paraloid, and add the micro balloons and acrylic slowly, stirring all the time. For the first test I made up a thick putty-like mixture:

Putty-like mixture.

This I scraped onto the boards with a small spatula, pressing it down into the holes – like using Polyfilla. It did not look great, and the solvent evaporated so quickly that it became really stringy and difficult to work – sticking more to the spatula than the wood.

Filling holes with the putty-like mixture – area #1.

So I thinned it down, by adding a splash at a time of the 10% Paraloid solution, until the filler was the consistency of double cream. This needs constant stirring, as the mix tends to separate into the balloons on top and the solvent underneath – kind of like a horrible scum/foam!

Thinner filler mix

Using the pointy end of the spatula, I was able to dribble this mix into the areas to be filled, agitating slightly to make sure of an even coverage. Leaving the filler raised above the surface of the wood to be sanded/cut down later.

Area #2, filled with the thinner mix.

When semi-dry, I was able to scrape off the top layer, so the fill was about level with the surface of the board, and then re do the process after it had completely dried, as the fill had shrunk very slightly. The end results of both areas #1 and #2 were sanded down with fine grit sandpaper.

Area #2 after treatment.

Area #2 after treatment.

Area #1 after treatment.

Area #1 needed some further fills after sanding down, as there were still some voids. I did this with the thinner mixture, and sanded again afterwards.

Area #1 after second treatment.

This type of treatment has worked really well for these small holes, I have yet to experiment with the solvents (ethanol/acetone) to remove the filler residue from around the holes. But if that works, then the fills can be tidied up a lot easier, and will cut down on the amount of sanding the fills need.

Wooden Board Infilling pt. 1

I’m currently working on a few large bindings, one of which has wooden boards that have become a feast for woodworm. All along the joint edge where I’ve uncovered the board by removing the previous deteriorated red rotten reback leather, there’s evidence of quite a lot of insect damage. The wood has become crumbly and needs to be strengthened, consolidated and filled before the boards can be reattached to the textblock and it has a new re-back.

Joint Edge of Back Board

After some research and consultation with PZ trainee Gwendoline (who has infilled wood in a previous project) I decided that the wood should be consolidated with Paraliod B72 before being filled. This will prevent seepage from the infill into the wood and reduce any damage from the infill material.

To make up the Paraloid solution you will need:
–  a clean glass jar with a tight fitting lid, large enough to take 100ml solution
– an accurate measuring flask
– an accurate set of scales
– Paraloid B72 ‘beads’ (suppliers below).
– Acetone
– Ethanol
– cheesecloth
– string
– permanent marker
– extra jam jar.

To make up a 10% solution follow these instructions:

– Weigh out 10g of Paraloid and fasten into a bag using the cheesecloth and string.

10g Paraloid

Paraloid and cheesecloth

Paraloid in cheesecloth ‘bag’

– pour 100ml water into your clean glass jar and mark off where the liquid comes to with a  marker. Then pour out the water and dry up the jar.

100ml marked off.

-Measure out 85ml of Acetone and pour into a seperate clean jar. The measure out 15ml of Ethanol and pour into the same jar.

– Place the bag of Paraloid into the clean jar and then carefully fill up with the Ethanol/Acetone mix to the marked line and discard the rest.

– Lift up the bag so it’s suspended in the sovent leaving the string dangling outside and then screw up the lid tightly.

Paraloid suspended in solution.

– Leave to dissolve overnight, then discard the cheesecloth and string, squeezing out whilst wearing gloves.