I'm going through How to DESIGN, BUILD and TEST SMALL LIQUID-FUEL ROCKET ENGINES and am confused how their sample engine is physically built together. here

This is a picture of their assembly where the combustion chamber(8), cooling jacket wall(9), injector plate(the piece of metal in between the fuel injector and the oxygen injectors), engine mount(5), and upper shell(1) are connected as one.

The text did not directly say how the upper shell(1) and the injector plate are to be joined. Would they normally be welded together where they meet? I assume around the oxygen chambers that are in between the injector plate and upper shell(1). Does that mean that the combustion chamber(8) and the outer cooling jacket wall(9) are also welded together where they meet at the top and bottom of each piece?

I have no experience with how an engine like this would physically be put together so I don't know of any of the standard practices that metalworkers use.

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    $\begingroup$ What about reading this very similar question? $\endgroup$
    – Uwe
    Mar 23, 2019 at 16:33
  • $\begingroup$ The reference that we are both looking at only mentions "The shell will also feature a method of attaching the injector and for mounting the engine to a test or thrust stand. As shown in Figure 8, these two mounting requirements can be easily combined to simplify the design." Looking at this picture I don't intuitively know what the welding process is like to combine two pieces of metal like this. $\endgroup$
    – MAP3
    Mar 23, 2019 at 16:58
  • $\begingroup$ The answer to your question would be obvious if given a complete set of engineering drawings; the illustration shown appears to be only part of what may not even be a buildable design. The purpose for which the drawing was created may only be to illustrate concepts, not be a part of a real engineering drawing set. Anyway, it may be possible to design components for assembly without welding (securing everything with bolts) and using metal gaskets for seals where not directly exposed to combustion gases, but it would be heavier than welding and differential expansion could make it unworkable. $\endgroup$
    – Anthony X
    Mar 23, 2019 at 22:38
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    $\begingroup$ Not a rocket engineer so not going to make an answer but first guess would be that part one is welded on the outside edges (note that leak will just allow 02 to escape so relatively safe) and the bottom chamber liner (probably consumable) would be lathed to a taper cut bigger at the top (can only come out when engine apart) and oversize so that it is clamped between the coolant chamber and injector body when the halves bolt together. Will still leak coolant when cold due problems getting two different tapers to match so only really good for water and orientations where it can drain. $\endgroup$ Mar 23, 2019 at 23:50