Pacific Spaceflight is a small group of volunteers that has spent the last decade developing an open source, DIY spacesuit in their members' living rooms. This fall its creator will fly to over 60,000 feet in a hot air balloon, known as the Armstrong Limit, the point at which exposed body fluids will boil away if not protected in a pressured vessel. [A post on Medium provides a] deep dive into the story of Pacific Spaceflight and how to build your own spacesuit.

Here is an excerpt from the report:

There are two main types of spacesuits: Intravehicular activity (IVA) suits worn inside spacecraft, and those worn outside for extravehicular activities (EVA). IVA spacesuits are mostly there as a backup in case of an emergency, like the sudden loss of pressure in a spacecraft. This makes them inherently simpler since they don't have to account for things like radiation exposure and the gloves can just be rubber gloves similar to those you might use to wash your dishes. [...] Smith's first suits were made by modifying old scuba diving suits to fit his needs. Yet as he became more familiar with pressure suit design and his own requirements, he started to assemble everything from scratch. These days, he and the other Pacific Spaceflight volunteers cut their own fabric and pretty much make everything on their own or repurpose common household items as necessary (Smith said one of the few things the group can't make on its own is the suit's zippers).

(Via Slashdot.)

It turns out that Otto Willi Gail provided extensive details for spacesuit testing in his exciting 1929 novel The Shot Into Infinity:

(Spacesuit testing circa 1929)

Korf opened the doors of the chamber built into the wall, entirely finished in rubber and provided with an airtight door.

"Two things (aside from cold which can be overcome) seem to make a stay in space impossible for human beings; the absence of pressure and the lack of air. I'm going to pump the air from this room, which really amounts to nothing more than a laboratory flask on a large scale, so that the interior will be like airless and pressure-less space."

With great excitement the visitors watched Korff take from the drawer a bundle, which he opened up.

"This is a suit made from rubberized leather, like a diving suit, and absolutely airtight. By means of a special air magazine so much air is constantly produced in the suit that there is a constant pressure of one atmosphere, regardless of the external pressure.

Suchinow silently slipped into the costume and allowed Korf to screw on the helmet with the oxygen chambers. Then he placed himself in the center of the chamber. In one of his leather-covered hands Korf placed a burning candle. Then he closed the door, through the glass window of which all the proceedings could be witnessed. They could clearly hear an electric bell in the chamber, which Korf switched on.

The pump began to work. The candle flickered and went out. The bell seemed to sound fainter and fainter, though the clapper kept on striking. korf shut off the pump.

"Now, except for weight and heat, the same conditions prevail in this chamber as in space. Yet Mr. Suchinow, with whom we cannot communicate at present, certainly feels alright."

Sam looked through the window, and laughed out loud. In fact Suchinow presented a very comical appearance. The suit had swelled to its fullest extent and had taken on the shape much like that of the favorite rubber dolls of festival times.
(Read more about Otto Willi Gail's spacesuit testing)

Gail refers to the suits as pneumatic suits; the phrase "space suit" was first used in 1931 by Golden Age scientifiction duo Nat Schachner and Leo Zagat (see space suit from The Emperor of the Stars).