In the holes drilled in a wooden tube in the concrete wall, there is always a lot of sand and dust. To remove them will help plastic or metal tube by simply inserting it into the hole and how to blow into it (but mind your eyes!).
S. DOROFEEV, p. vokhtoga, Vologda region.
Recommend to read
How did we make a scuba gun?
Imagine this: you're standing by a river, the water is crystal clear, and fish are darting just beneath your feet. But instead of store-bought gear, you're holding a speargun built with...
SWITCH WITH PROTECTION
In many technical constructions, devices, in laboratory and bench equipment, automobiles used a DC electrical supply voltage of 12 V overload protection, which can lead to spontaneous...
