kiwi303 Posted June 20, 2012 Share Posted June 20, 2012 As far as Scuba tanks go, you can put a and they will not explode. But be turned into a rocket pack they certainly will be. I would not bet my life on the scuba tank not exploding, but it shows how a properly designed and inspected tank being run within it's design parameters handles a breach. On air compressor tanks watch out for rust or physical damage that may compromise the strength of the tank if you go for a used unit. With the exploding SCUBA tank phenomonen, putting a bullet through a tank is not germane to discussing self failure of a tank due to metal fatigue. The big problem is with Aluminium tanks which get fatigued and crack, after time they end up with a spiderweb of cracking and when one finally lets go, the stress risers cause all the other cracks to go, separating the ali bottle into several pieces. Metal tanks are spring steel, so if not permitted to rust, have an essentially infinite life, if a rust hole develops the air punch through causes them to peel open, but nearly alweays remain in one piece. A bullet through a tank will punch a neat hole which will then open up, but is not itself a longitudal crack or part of a network of metal fatigue stress lines. Air compressor tanks are (at least that I have seen) universally steel, so they are unlikly to explode into shrapnel like an aluminium tank, but rather pop at a deep rust pit and all the air whistle out. At the lower pressure, the air blast MIGHT be enough to tiop the compressor over, but it's certainly not going to turn into a bottle rocket. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 20, 2012 Share Posted June 20, 2012 "Air compressor tanks are (at least that I have seen) universally steel, so they are unlikly to explode into shrapnel like an aluminium tank, but rather pop at a deep rust pit and all the air whistle out. At the lower pressure, the air blast MIGHT be enough to tiop the compressor over, but it's certainly not going to turn into a bottle rocket."<br class="Apple-interchange-newline"> Compressed air kills. <4psi will introduce an air embolism through proper misapplication during horseplay, causing a stroke and possibly death. <2.5 bar can separate epidermal layers accompanied by searing pain you never want to experience. 3 bar seating a rim on a passenger car tyre that jumps a bead seat can break your arm. 4 bar in a semi truck split rim not properly seated and in a safety cage can break both your legs, or kill you. 8 bar in a receiver with the right conditions can cause deadly and catastrophic failures... I have seen them in ASME Coded vessels where HAZ areas around end cap welds were weak, and something blew off. One of the reasons I specify getting a used INDUSTRIAL unit in the USA at least is that they generally have ASME coded vessels (and in California they are SIGNIFICANTLY thicker than run-of-the-mill home compressors.) The ASME code has tanks that are almost 100% thicker than home compressor tanks due to their intended service. So the corrosion factor is larger, the welds are better, etc... Most home compressors sold in the USA do NOT comply with ASME Code for a pressure vessel. This is very common where a shop goes in to Home Depot to buy a "5 HP Compressor" and put it in their shop, only to find when they try to permit the vessel with the state that it is unapproved for use in a commercial enterprise! "Home use compressor" means "shite tank"! A 3/4" fitting that comes loose from the receiver because it was a cheap 0.125" wall tank that was a little rusty and the fitting got bumped will come out with ANNOYING force! Annoying to the point of a blood blister and not being able to walk for three days when it hits someone on their kneecap! The problem with corrosion in vessels is SO EASY to combat: if you have a new compressor, put some HCl dilute and then some TSP to wash the interior...mix some industrial 2 part epoxy paint and pour it in an opening plug them up and roll it all around to coat the interior. Let it set, reassemble it with proper sealants to keep water from getting to any exposed threads, and put it in service. Rust will not be an issue in your lifetime. Ameron has some great coatings but they aren't cheap. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 20, 2012 Share Posted June 20, 2012 And "Jaws" shows conclusively that an 80CF Steel SCUBA Tank when hit with a 30-06 M1 Garand will blow the head off a Great White Shark when it concussively explodes. Quote Link to comment Share on other sites More sharing options...
kiwi303 Posted June 20, 2012 Share Posted June 20, 2012 And "Jaws" shows conclusively that an 80CF Steel SCUBA Tank when hit with a 30-06 M1 Garand will blow the head off a Great White Shark when it concussively explodes. Nah Nah Nah... You must be meaning a Steel 72 on a +10% fill! They didn't get Steel 80's until well after the Ali 80's made the size popular enough that Newbies would ask for an "80" for anything. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 21, 2012 Share Posted June 21, 2012 Yeah, and it floated all by itself as well!!! Remember Hooper was a rich kid, he filled his own tanks. You can make a 72 an 80 if you got a good Bauer or Sulzer and bypass / lag some items! Quote Link to comment Share on other sites More sharing options...
rejracer Posted June 21, 2012 Share Posted June 21, 2012 Thanks Tony, I did not know about the home use compressors not having to meet the same certification. JSM, I've been very happy with the ingersol rand gun. I don't use it commercially, but I've been using it for 11 years without a glitch. The particular gun I am referring to is rated at somewhere around 600ft lbs of torque. The reason it uses less air is that on high you pull the trigger and bolts are off before you know it. I usually use it on it's lowest setting. The other guns I use take much more time and thus more air. The actual rate of consumption may be higher on the ingersol. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 22, 2012 Share Posted June 22, 2012 It is the consequence of "cheap sells"--- in air compressors there is something called "API-672"A compressor in the 800hp range would likely cost close to $4,000,000 if fully compliant. That same compressor, designed to "good engineering practices" - meaning it makes the same airflow and pressure, just not complying with all the bells and whistles required with compliance with API672 will run about $175,000 !!! Same production--- and really a guy making fiberglass in a centrifuge likely doesn't need the API unit. Same goes for ASME Coded pressure vessel. Thing is, even though the home units have "good engineering practices" designed receiver for the most part, meaning it won't blow up on you... The thinner tank will be susceptible to corrosion much faster than an ASME Coded Vessel. Thickness is the main component against corrosion in ASME Codes. In Europe, you see a lot of galvanized tanks. Some places like Ozone Generators for water districts will be all stainless steel. And those stainless tanks are THIN (because they don't corrode) but due to this thin construction can RING LOUDLY when hit with pulsations. A used home compressor should always have a tank inspection--if it's rusty I'd pass. That same level of corrosion in an ASME tank will still be good for another 25-50 years! And they don't ring! Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 26, 2012 Share Posted June 26, 2012 Lookie what I found! An example for the kiddies. Read what happens and why! http://http://www.ingersollrandproducts.com/_downloads/CPSC%20Release%202002.pdf Quote Link to comment Share on other sites More sharing options...
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