- Thread starter zardoz
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Wallace
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Is there a HAZ on the weld shown @2:48 showing a possible repair? Paint looks burnt.
AndyStobbs
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Have you forgotten to include whatever point you're making in that last post?
Wallace
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I'm not trying to make any point just clarify the part you may have misread in my first post by adding "Paint looks burnt".
Heat tint colours and a HAZ are two different things, can't see the later without etching a sample to highlight the microstructure [/pedantic]
I thought the point was obvious... typically pressure vessels are painted after they've been welded together by weldors that are following a WPS they've qualified to and then been subjected to NDT & hydraulically tested. Burnt paint around a weld suggests that a fitting may have been snotted in by some numpty that doesn't have a clue what they're doing, what NDT is (or thinks a miss spelling of BFH) etc
Here's another one http://www.cdc.gov/niosh/face/stateface/ca/05ca010.html fortunatly it was investigated properly and they found the cause instead of claiming it was ****** based on pumping up a crimped oil can to 50psi
I thought the point was obvious... typically pressure vessels are painted after they've been welded together by weldors that are following a WPS they've qualified to and then been subjected to NDT & hydraulically tested. Burnt paint around a weld suggests that a fitting may have been snotted in by some numpty that doesn't have a clue what they're doing, what NDT is (or thinks a miss spelling of BFH) etc
Here's another one http://www.cdc.gov/niosh/face/stateface/ca/05ca010.html fortunatly it was investigated properly and they found the cause instead of claiming it was ****** based on pumping up a crimped oil can to 50psi
rtbcomp
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From that link "Testing performed by an independent laboratory found that there were products of combustion in the tank. Independent studies have shown that use of an improper oil type can lead to accumulation of oil residue in compressor receivers, and that this residue can lead to combustion and explosions."
That's another source blaming oil for an explosion in a tank. I'm suprised we haven't come across this before.
That's another source blaming oil for an explosion in a tank. I'm suprised we haven't come across this before.
brightspark
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and still has nothing to do with a tank blowing up due to corosion 
so is everyone going out to get there tanks tested along with all the home made blasting pots made from callor gas bottles and the cheap thin bought pots?? i think not
so is everyone going out to get there tanks tested along with all the home made blasting pots made from callor gas bottles and the cheap thin bought pots?? i think notAndyStobbs
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You don't seem to have much faith in the abilities of practical people to make a good job of something unless they have read the procedure off some piece of paper first.
My post was intended as a response to moving a compresser into a shed because (i assume) the poster wasn't overly confident in his welded repair, clearly his repair is just as sound as all of the other welds made on the receiver, he might have even managed it without a string of quals and a WPS.
As for the static, when compressors start coming with an Earth strap I will worry about a static explosion, until then I think I will soldier on in ignorance.
rtbcomp
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If you're referring to this in the link I posted "In other air compressor accidents, static electricity sparks have also been identified as a source of fires and explosions." I suspect the static sparks ocurred inside the tank, a bit like lightening occurs in the atmosphere, so an earth strap would be useless.
Im ok with my welded repair, its the mess the p.o made of the job first that worried me the most as I was given it as a freebie tank that the porus weld repair LEAKED from multiple pinholes in, I cut it larger and made a o/s bush and welded that in to hopefully eliminate any fat fingered repair work as it looked like they'd used a stick welder with some rods grandad dug up out the garden, but putting it in its own outbuilding was the best decision ever from a useability point of view, never mind blast protection.
However, I've had 9 years use out of it even if the masses would have thrown it out as too dangerous to attempt, and even if it was brand new, came with a cert, was hydrotested officially, I'd STILL house it in that outbuilding for the other adavantages, and thats the point I was trying to make. Substantial compressor sheds are great for all sorts of reasons. Its bad enough to hear the air rushing on a die grinder without the pump grinding away in the same room heating the local environment up. Plus you get cool air intake, when your painting it doesnt all end up in the air filter on the compressor, you can silence the snot out of the shed its in etc etc.
Once you have bothered to make one, the air just becomes part of the normal services in the workshop, like power or water. You need a airpoint, you use a extension hose but if you find yourself doing it a couple of times a month just run a extra drop to that machine.
However, I've had 9 years use out of it even if the masses would have thrown it out as too dangerous to attempt, and even if it was brand new, came with a cert, was hydrotested officially, I'd STILL house it in that outbuilding for the other adavantages, and thats the point I was trying to make. Substantial compressor sheds are great for all sorts of reasons. Its bad enough to hear the air rushing on a die grinder without the pump grinding away in the same room heating the local environment up. Plus you get cool air intake, when your painting it doesnt all end up in the air filter on the compressor, you can silence the snot out of the shed its in etc etc.
Once you have bothered to make one, the air just becomes part of the normal services in the workshop, like power or water. You need a airpoint, you use a extension hose but if you find yourself doing it a couple of times a month just run a extra drop to that machine.
