There are quite a few resources around online that you (the U.S. Government) has already paid for. Many of them are available free.

On the Origami List , a recent poster commented about:

U.S. Army
Corps of Engineers "THERMAL SPRAYING: NEW CONSTRUCTION AND
MAINTENANCE" Engineer Manual ... it's relatively recent, being dated
29 January 1999.

It's available at:

http://www.usace.army.mil/publications/eng-manuals/em1110-2-3401/entire.pdf

There are many other U.S. Army Corp of Engineers publications available at

• http://www.usace.army.mil

Other items can be found by searching the (pretty well done, actually) Government "search" site at:

• FirstGov.gov
  

I happen to know there is a good "Intro to Welding" manual floating around titled Welding Theory and Application, although a free link to it escapes me at the moment. Its a U.S. Army training manual (its Training Circular TC 9-237 - search for it...). I'm not going to make it available since I'm not sure its "free", but if somebody can find a link or more information about it, please pass it on.