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Used a 3/8 inch backing plate on a 2 inch thick flange and it held for a week
We were short on the right gear for a job at the old power plant in Gary, so I tried a thinner plate than spec called for. The weld held fine under normal pressure, but it started to stress crack after seven days of the full 150 psi cycle. Learned that saving time on material prep can cost you double later. What's the smallest you've ever gone under spec and gotten away with it?
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caseyblack5mo ago
What pressure was it rated for originally?
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ivan_schmidt5mo ago
You asked about the original rating. That's the key detail everyone overlooks. People see a modern standard and assume it was always that tough. Old specs were often much lower, which explains why some things fail over time. They were never built for what we expect now.
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the_sam4mo ago
Original rating was probably stamped right on the side in faded paint, half an inch from a rust hole. Bet it says something like "50 PSI max" when people are trying to push 150 through it. Modern engineers just look at the thread size and assume it can take whatever the new pump puts out. Saw a guy try to use a 1940s boiler valve on a modern system once. That thing was basically a hand grenade waiting to go off. Ever blown a gasket because you trusted a number that wasn't there?
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