Blocking powder

Gold leaf needs an adhesive. When putting gold on leather bindings the traditional adhesive, called a glaire, was egg whites. More modern glaires like Fixor or BS Glaire, use shellac. Here is a blog post I made on making your own glaire: you can find it here.   It was part of a struggle to figure out why I was being sent unusable Fixor (a modern glaire) without any real logical explanation and then figuring out how to easily make better glaire, that actually worked for less cost.

A hundred years ago gold leaf was used on cloth bindings as well. But you can’t use a liquid glaire on cloth because it would stain. You could, I suppose, make an impression and then carefully put the gold in that space, but if the impression was made using a blocking press, you’d have to fill the impression without moving the book in the press and . . . it would be pretty much impossible I think.

Blocking powder is a powdered glare. It is also made from shellac.

I first learned about blocking powder in Sweden where Per Cullhed used it when tooling. He would use Fixor for his gold tooling. But there are often losses in tooling, places where the gold doesn’t stick. You try again with the gold and if it doesn’t stick the second time often you have to re-glaire the spot. And then wait for the glaire to dry before proceeding. It takes time. Some might think it wastes time.

Per would use blocking powder in the spots that needed reglairing, which meant that he could re-tool the spot immediately and successfully.

When I returned from Sweden I tried to buy it from the usual suppliers, but no one had it. A while ago, many years after returning from Sweden, I asked around and found a few recipes.

I made this one and it’s worked really well. It’s from Pleger’s book, Bookbinding and Its Auxiliary Branches, Part 3: Blank, Edition and Job Forwarding, Finishing and Stamping, on page 234:

1 part gum arabic
1 part gum sandarac
1 part gum mastic

I mixed them in a coffee grinder to a very fine powder and ended up with about a third of a cup. Which is a lot considering how little is used each time.

David Lanning, of Hewit Leather, had another recipe:

25% French Chalk (Tailor’s Chalk)
75% Finely Ground Shellac

There is no question that would work as well.

It’s interesting to note that Pleger does not like using “gilding powder.” He writes, “. . .beyond the lettering of individual names in addition to the afore-mentioned materials it should not be used. . . .”

Pleger actually has two other recipes, one using gutta-percha which I wanted to use because it sounded like a fun thing to use, but I couldn’t find it anywhere. In spite of its use in dentistry, and that my sister works in the dental industry, I couldn’t find it anywhere.

His third recipe is:

1 part shellac
2 parts copal

I purchased the materials from Kremer Pigments. The cost of the three items in the first recipe was about $60 for what feels like a lifetime supply.

To use the powder you take a fine bristled brush and dust it evenly over the area you are filling in. You might have to vary the heat of the tool a little bit, of course. Then pick up the gold and tool it.

It really is just like any other finishing. I do think it would be a bit of a pain to use it over a whole cover, but I might be wrong about that. And we know that Pleger would have words with you if you did that.

Try it. You’ll end up thanking Per! And he deserves it.