For difficult repairs requiring highest bond strengths. The glue itself consists of the air bladders of sturgeons. In recent years, the drastically reduced fishing quotas have made this glue a precious commodity. Glue line from light yellow to nearly transparent.
Glues of animal origin are simple to use, resist aging and can be softened again by heating, which makes them very useful for repairs. In contrast to synthetic glues, they can be overpainted and pickled. Also suitable as priming for painting and gilding. Cold water is added to the glue, which is left to soak. It is then carefully heated in a water bath.