Space Tug by Murray Leinster — Read

Time passed. Hours, then days. Things began to happen. Trucks appeared, / loaded down with sacks of white powder. The powder was very messily / mixed with water and smeared lavishly over the now waterproofed wooden / mockup of a space ship. It came off again in sections of white plaster, / which were numbered and set to dry in warm chambers that were / constructed with almost magical speed. More trucks arrived, bearing such / diverse objects as loads of steel turnings, a regenerative / helium-cooling plant from a gaswell -- it could cool metal down to the / point where it crumbled to impalpable powder at a blow -- and assorted / fuel tanks, dynamos, and electronic machinery.

Ten days after Mike's first proposal of concreted steel as a material / for space ship construction, the parts of the first casting of the / mockup were assembled. They were a mold for the hull of a space ship. / There were more plaster sections for a second mold ready to be dried out / now, but meanwhile vehicles like concrete mixers mixed turnings and / filings and powder in vast quantities and poured the dry mass here and / there in the first completed mold. Then men began to wrap the gigantic / object with iron wire. Presently that iron wire glowed slightly, and the / whole huge mold grew hotter and hotter and hotter. And after a time it / was allowed to cool.