Factual error: No gearbox problem would cause the noises in the episode, it was a clutch problem.
Factual error: Bert is using an oxygen-acetylene torch, not butane, and the stop valve is NOT the large T piece on the regulator. Butane cannot cause a heart attack.
Chosen answer: As far as hanging new wallpaper, there is no need to brush on any additional product once it has been pasted to the wall. It appears Helena may be doing an extra decorative step by applying a liquid glaze over the wallpaper to give it a more distinctive look, perhaps creating a sheen effect on the surface. Glaze can also be tinted to give a muted colored tone. It could also be a protective sealant. However, to remove old wallpaper, a product is brushed on that dissolves the old paste so the paper can be easily scraped off.
raywest ★