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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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Air Compressor Safety?
I don't have an air compressor yet, I know nothing about them, and
don't know anyone in person that owns one, but I was thinking about getting one for running an impact wrench, air ratchet wrenches, and occasional painting. After some Google searches, I came across a few threads about air compressor tanks exploding. It was sometimes caused by corrosion, sometimes a bad relief valve, or bad pressure switch, or any combination of the 3. I've also read that bad welds, a weak tank, or other problems can contribute to a potentially fatal explosion. I was originally going to buy the Harbor Freight 47065 "4-1/2 HP" vertical compressor for about $150. It's oil lubed, so I thought it would be a much better (and cheaper) alternative than picking up a cheap oil-free compressor from Wal-mart. This would be for light occasional use anyway, so I'm not too concerned about full cast iron pumps or belt drive. My other alternative is to drop $400 on an oil lubed Craftsman or Campbell-Hausfeld. However, we all know Harbor Freight products are Made In China which is not a country known for making high-quality products. If I buy a cheap Chinese compressor, do I risk poor welds on the tank? A weak tank made with poor grade iron? A pressure relief or pressure switch that's likely to fail? If I'm risking my life by going cheap, I'd definitely spend the extra money. If the HF compressor is perfectly safe, then I'd rather buy it and save the money. Anyone have experience with the HF compressor? I know compressor tank explosions are few and far between, but I'm a very safety-oriented person. Also, a quick question about compressors - when the compressor is not being used, do most people leave the tank pressurized at all times and the compressor plugged in, or do most people unplug them and bleed the pressure out of the tank? Thanks, Shawn |
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Air Compressor Safety?
I wouldn't worry about explosions. I imagine it could happen, but a tank
would have to be very weak in order for it to happen catastrophically. These tanks aren't pressurized to 3000PSI like a SCUBA tank. It seems much more likely that you'd just have a leak. I had a blow off valve go out once and nothing drastic happened; just a very loud whistling sound as 150PSI bled down (though it scared the hell out of me...). I've had cheap and expensive compressors and tanks (one that I've had for twenty years) and they're fine. Just put a dehumidifier inline if you can to keep the water out of the tank and tools and/or drain the tank periodically and you'll be fine. Regards, Peter "Shawn Lin" wrote in message om... I don't have an air compressor yet, I know nothing about them, and don't know anyone in person that owns one, but I was thinking about getting one for running an impact wrench, air ratchet wrenches, and occasional painting. After some Google searches, I came across a few threads about air compressor tanks exploding. It was sometimes caused by corrosion, sometimes a bad relief valve, or bad pressure switch, or any combination of the 3. I've also read that bad welds, a weak tank, or other problems can contribute to a potentially fatal explosion. I was originally going to buy the Harbor Freight 47065 "4-1/2 HP" vertical compressor for about $150. It's oil lubed, so I thought it would be a much better (and cheaper) alternative than picking up a cheap oil-free compressor from Wal-mart. This would be for light occasional use anyway, so I'm not too concerned about full cast iron pumps or belt drive. My other alternative is to drop $400 on an oil lubed Craftsman or Campbell-Hausfeld. However, we all know Harbor Freight products are Made In China which is not a country known for making high-quality products. If I buy a cheap Chinese compressor, do I risk poor welds on the tank? A weak tank made with poor grade iron? A pressure relief or pressure switch that's likely to fail? If I'm risking my life by going cheap, I'd definitely spend the extra money. If the HF compressor is perfectly safe, then I'd rather buy it and save the money. Anyone have experience with the HF compressor? I know compressor tank explosions are few and far between, but I'm a very safety-oriented person. Also, a quick question about compressors - when the compressor is not being used, do most people leave the tank pressurized at all times and the compressor plugged in, or do most people unplug them and bleed the pressure out of the tank? Thanks, Shawn |
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Air Compressor Safety?
I believe all pressure vessels have to pass an ASME test in order to be
marketed. Just how this fits into the handling sequence of a machine coming in from China, going through HF's warehouse, etc, I don't know. |
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Air Compressor Safety?
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Air Compressor Safety?
About a year ago, I bought a US made, ASME certified compressor made by
Campbell Hausfeld and sold at Home Depot under their Husky brand. The top weld had two holes, one of which leaked. I would suggest paying more and getting Ingersoll Rand, Quincy, etc. |
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Air Compressor Safety?
Snip
IMPORTANT SAFETY NOTE: If you plumb a compressor permanently in the shop do NOT use any sort of PVC plastic pipe for the air lines. When it breaks, it grenades, and that can be just as deadly as it sounds if you're in the wrong place at the wrong time. Use copper pipe (soldered or brazed), black iron or galvanized pipe, with a piece of hose as a vibration isolator between the compressor and plumbing. There are plastic pipes designed for air use but they only go to 1/2" which may not be large enough for a big comp. They are reliable though and the push fittings are quick to install. John |
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Air Compressor Safety?
John Manders wrote:
Snip do NOT use any sort of PVC plastic pipe for the air lines. When it breaks, it grenades, There are plastic pipes designed for air use but they only go to 1/2" which may not be large enough for a big comp. They are reliable though and the push fittings are quick to install. There are larger plastic pipes that are rated for air use. They're green plastic (I think ABS.) The fittings are glued on with a solvent cement. One brand name is Chem-Air. They are expensive. -- Steve |
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Air Compressor Safety?
Bruce L. Bergman wrote:
And I sincerely doubt that any ASME Inspectors have been within a thousand miles of any Harbor Fright factory... How about UL inspectors? I don't know about HF, but I noticed that Homier's compressors don't have UL markings on them. One of them had a little tag warning the user to unplug it when not in use to reduce the risk of fire. If you want the insurance on the shop building to stay in force, you'll need a compressor with an ASME certified tank, and the paperwork on file. A compressor in a commercial setting needs to have a permit from the state boiler inspectors, and be re-inspected periodically. The requirements will vary from state to state. -- -- Steve |
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Air Compressor Safety?
Bruce L. Bergman wrote in message . ..
Keep the tank drained well - every time you use it, drain it. No water, no rust. (Well, almost.) If you like gadgets or have people using the system that can't be bothered to drain it manually, you can get automatic drain valves for stationary compressors that do the draining every time the motor cycles. Thanks for the reply! Automatic drain is a great idea! I tend to be forgetful so this will come in handy (I know I have scared the wife several times by accidentally leaving the soldering iron plugged in overnight). And I sincerely doubt that any ASME Inspectors have been within a thousand miles of any Harbor Fright factory... If you want the insurance on the shop building to stay in force, you'll need a compressor with an ASME certified tank, and the paperwork on file. Exactly my concern. There's no mention of ASME anywhere in the Harbor Freight ad for this compressor. The $400 Sears portable compressor I was looking at (the cheapest oil lubed portable vertical compressor they offer) does have an ASME tank. I was originally going to buy the Harbor Freight 47065 "4-1/2 HP" vertical compressor for about $150. It's oil lubed, so I thought it would be a much better (and cheaper) alternative than picking up a cheap oil-free compressor from Wal-mart. This would be for light occasional use anyway, so I'm not too concerned about full cast iron pumps or belt drive. My other alternative is to drop $400 on an oil lubed Craftsman or Campbell-Hausfeld. [snip] Consider any complex hand or power tools from Harbor Fright (including their air compressors) to be disposable. {If} ^w strike that... /When/ they break, getting replacement parts and service are going to be a problem, and it'll often be cheaper to throw it away and get another. That's true, and I realize that. I just want a portable compressor for light use for the next 3-5 years. After that, I plan to have a new house built and a larger, higher quality compressor installed remotely in its own room. A friend of mine is doing just that in his house with air plumbed to both the garage and workshop, it's a pretty slick setup. The compressor I get now only HAS to last 3-5 years, and I'll probably only use it a few times a year to run an impact, inflate tires, light painting, blowing out the inground sprinkler system, etc. The real work (like painting whole cars) can wait till I can get moved into the new house and have a real compressor. IMPORTANT SAFETY NOTE: If you plumb a compressor permanently in the shop do NOT use any sort of PVC plastic pipe for the air lines. When it breaks, it grenades, and that can be just as deadly as it sounds if you're in the wrong place at the wrong time. Use copper pipe (soldered or brazed), black iron or galvanized pipe, with a piece of hose as a vibration isolator between the compressor and plumbing. Thanks for the warning, I read about that too. The compressor I get now will just be a portable so it won't be permanently plumbed. However, when I do buy a permanent compressor, I'll use copper. That's also what my friend used, so he should be able to give me some good pointers when I get to that point. Thanks again, Shawn |
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Air Compressor Safety?
"AL" wrote in message news:v0shb.717495$YN5.636545@sccrnsc01...
About a year ago, I bought a US made, ASME certified compressor made by Campbell Hausfeld and sold at Home Depot under their Husky brand. The top weld had two holes, one of which leaked. I would suggest paying more and getting Ingersoll Rand, Quincy, etc. There is a very graphic reminder of the power of compressed air on www.metalbashatorium.com/safety.htm bottom left from memory. Don't get complacent about compressed air. Glenn |
#12
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Air Compressor Safety?
see post in "air compressors??" thread about new "cheap" compressors.
RE exploding - not likely with corrosion - it will cause a hole and air will escape - exploding requires a sudden release, and unless the welds are bad or something, that won't happen. summary of suggestion re compressors - look ONLY at CFM - for an impact wrench where you don't run it long, the tank size is important, but for spraying or sand blasting, etc, you need steady CFM - and 2 CFM is not enough - you need 8 to 10 CFM minimum at 60 PSI, better to have 15 at 120 or above "Shawn Lin" wrote in message om... I don't have an air compressor yet, I know nothing about them, and don't know anyone in person that owns one, but I was thinking about getting one for running an impact wrench, air ratchet wrenches, and occasional painting. After some Google searches, I came across a few threads about air compressor tanks exploding. It was sometimes caused by corrosion, sometimes a bad relief valve, or bad pressure switch, or any combination of the 3. I've also read that bad welds, a weak tank, or other problems can contribute to a potentially fatal explosion. I was originally going to buy the Harbor Freight 47065 "4-1/2 HP" vertical compressor for about $150. It's oil lubed, so I thought it would be a much better (and cheaper) alternative than picking up a cheap oil-free compressor from Wal-mart. This would be for light occasional use anyway, so I'm not too concerned about full cast iron pumps or belt drive. My other alternative is to drop $400 on an oil lubed Craftsman or Campbell-Hausfeld. However, we all know Harbor Freight products are Made In China which is not a country known for making high-quality products. If I buy a cheap Chinese compressor, do I risk poor welds on the tank? A weak tank made with poor grade iron? A pressure relief or pressure switch that's likely to fail? If I'm risking my life by going cheap, I'd definitely spend the extra money. If the HF compressor is perfectly safe, then I'd rather buy it and save the money. Anyone have experience with the HF compressor? I know compressor tank explosions are few and far between, but I'm a very safety-oriented person. Also, a quick question about compressors - when the compressor is not being used, do most people leave the tank pressurized at all times and the compressor plugged in, or do most people unplug them and bleed the pressure out of the tank? Thanks, Shawn |
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Air Compressor Safety?
fudge in their figures, and so do tools. I have a "12CFM" compressor
that cannot run a "5CFM" air Random Orbital Sander! In actual fact the I bought a cheap ROS and returned it when I discovered my air compressor could not keep up with it. I bought a better quality/more expensive ROS and it seems to consume much less air. cs |
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Air Compressor Safety?
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Air Compressor Safety?
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