What happens when you weld on a sodium filled exhaust valve

[KBar]

Dino

After reading this web site on sodium filled valves. I would not want to touch them with a torch or any kind of weld. This site gives you all the technical data and how quickly it boils inside the valve.

http://periodictable.com/Elements/011/index.html

[Laiky]

I seem to remember from A&P school that the sodium will spontaneously combust on contacting air (O2?). I can remember our teachers telling us (WW2 old timers!) they used to throw them in the ocean so no one would accidentally open one up. Can't swear to it, since its been almost 20 years but that is what i remember.

[Laiky]

found this online, sounds familiar:
Handling Sodium Filled Hollow Valves
The machining and cutting open of sodium-filled hollow valves requires the appropriate caution. Special attention must be given to ensure that the cavity is not opened inadvertently, as sodium reacts violently to water or drilling and grinding emulsions. When sodium reacts to water, oxygen and sodium hydroxide are produced.

Examination and Disposal
Hollow valves is small quantities can be scrapped in the normal manner. There are no special instructions to follow. If sodium-filled valves have to be examined or disposed of in larger quantities, the cavities should be opened, either by drilling holes in two places without using a coolant, or by splitting the valve open in the middle. Valves prepared in this manner are to be placed in a bucket filled with water to neutralise the noxious effect of the sodium. After the chemical reaction has run its course, the valve can be scrapped in the customary manner. The sodium hydroxide is to the respective local regulations.

Safety instructions
Because of the violent chemical reaction and the release of hydrogen when sodium reacts with water, the valves should be neutralised only in well ventilated rooms or out of doors. Contact with the skin and eyes is to be avoided in any case. Sodium should therefore be handled only by properly trained staff wearing the appropriate protective clothing (gloves, goggles, etc.). The customary safety regulations governing the handling of abrasive and caustic material and explosive gases are to be observed.