Date: Mon, 9 Dec 1996 02:17:07 -0800 (PST) From: Mike West Subject: The terror of "gas cuts" The title says it. Mike Palima wanted to know what a "gas cut" was. This one has some amusement factor involved and maybe even some education value. While I was in the Navy, I was first a Boilerman and later a Machinist Mate and some other things we won't talk about. The gas leaks we had were large scale in comparison to the head of your car. High pressure steam at Superheated temperatures. That's what it's called. On the old ships the press/temp was 600 psi at 800 degree temp. Makes some almost efficient motivation. The steam has to travel maybe a 1/4 mile before it is used in the Turbines The newer ships use 1200 - 2000 psi and 1200 degree temps. That's almost up to the temps and pressures in your combustion chamber. You get a leak that starts with a drip, drip. If you can't get it fixed soon because of operating, you will soon have a groove cut across a 6 inch flange of solid steel 1/4" deep. All valve seats in the main steam system are "stellite" for this reason. It's about what the valve seats in some cars are made of. In the newer ships with 1200-2000 psi when they get a leak they just rope off half the fire-room where the leak is and don't go there. Rumour has it that 2/3 of the psycho cases in the Navy are boiler- men or MM's. When you get one of these leaks you have to find it first. Providing it doesn't find you first. Without getting into the politics or remarks on "brain capacity", our "Hero" steppeth forth. He buttons up everything and screws down his white hat. Grasping his magic wand indicator, a broom stick, he goes to find the leak. Picture a 19 year old beardless youth dressed for the Artic in a 150 degree boiler-room. Sucking air thru his teeth cause he needs to breath and if he opens his mouth too far his heart will fall out. Pucker factor is useless here, it's off the scale. And he's out here waving a broom handle over the general area like performing some religious ceremony with a scepter . All his crew-mates are back at the other end waiting and watching with bated breath. I never asked what they were waiting for 'cause I already know. Their next promotion. The first sumbitch who goes "psst" is going to eat this broom. I really have gone before the "mast" for this. If I catch him, I will do him great injury. When the steam cuts the broom handle in two you're real close. This is kind of "large scale" in comparison to your engine but the same laws apply. You have temps in the 2k range and pressures in the 1k range inside the combustion chamber. It doesn't take long for this to cut a puny little aluminum head. So torque those head bolts and be glad you're not waving a broom handle like "granpa had to do". west "This talking is becoming a habit."