|12-10-2011 06:55 PM|
|matt167||Well, after pricing the twin tank for that compressor at $252 w/o shipping, I decided the $59 12 gallon tank from Surplus center would have to do, and I just need to build a framework for the pump and tank.. So I got some 1x1 tubing, some 1/2" rod and some cotter pins, washers and 2 8" ball bearing lawn mower wheels. Decided 6'x3' was just about right, but after putting it togther, I think it's too big for just 1 pump.. so I'm thinking about adding another engine/ pump, running at a 125 PSI cut in and the other just above that , so the pressure would never drop below 125 PSI|
|12-03-2011 12:15 AM|
Guys using water tanks for air tanks rank right along with nut cases.
Use a tank designed for air pressure for air, use a water tank for storing shower water.
|12-02-2011 08:00 PM|
Look the fact you are still here only means you were lucky, those that weren't so lucky could not have posted that! There have been many people killed and maimed by cobbled up home built compressors, it happens more than you obviously know about. The statement that water pressure is no different from air pressure is so wrong it's ridiculous, the people who have been hurt thought the same thing! The usual argument is that the tanks have some air in them anyway but that does not make them safe since the air is usually at a comparatively low pressure and it's always just a small volume of air vs the water volume. Water tanks filled with high pressure air can, and have, killed people! I have seen two compressor explosions during my years of dealing with these things and I have seen several safety bulletins dealing with accidents that have occurred over the years and yes a couple of them involved using water tanks. I saw a 40 gallon tank peel the top of a Mack truck open like a sardine can and a 60 gallon tank took almost the entire back wall out of a two car garage, the truck incident left a man crippled and deaf in one ear and these accidents were using compressor tanks! Both had been repaired by welding cracks or holes in them which is another real NO-NO, NEVER weld on an air tank. You were lucky, nothing more, and what you had was extremely dangerous so please don't go around suggesting other people do the same thing!
|12-02-2011 06:15 PM|
or, you were just lucky it didn't burst.. If a water tank ruptures, it leaks and pressure drops right off. if an air tank ruptures, the tank can become a projectile because of the extended force, which is why the 2 tanks are diffrent for the most part
SOME tanks that are rated for water are also rated for air.
For this purpose, a propane tank is a much better candidate, as there rated for the pressures with a gas
|12-02-2011 06:05 PM|
Thats good info to know
No wonder my 60 gal tank held 100 lbs air pressure for 11 years it must have been a good strong tank..
|12-02-2011 05:56 PM|
|matt167||water cannot be compressed, and therfor, there is a lot more energy in compressed air than water that is under pressure.|
|12-02-2011 05:42 PM|
11 years I used that home made compressor
And I am still alive it held 80 lbs of water pressure. I don't think PSI is any different for air is it is for water. In the 1950's everyone had a home made compressor, similar to mine. Only one instance I ever heard of was a fella one Morning needed to pump his tire to get to work. He mistakenly left for work and forgot to turn off the compressor. The pressure built up and blew the plug out of the tank it traveled across the road and embedded in a telephone pole. penetration was nearly all the way through the pole. He did not have a blow off valve on his unit. Any way I'm alive and can talk about the good ole days, That ole rig paid for itself hundreds of times for me.
|12-02-2011 05:23 PM|
|12-02-2011 04:49 PM|
|matt167||yep. oldred and I have discussed that some time ago, as I actually have a simmilar setup, which uses a 1950's refigernant pump powered with a 3/4hp electric motor and an old water tank. It used to pump 120 psi if you let it, but has since been decomissioned for the most part due to the safety issues. it was never very efficent. it still runs and I have used it to pump up a lawn mower tire from time to time, but I never let the tank build pressure any longer.|
|12-02-2011 04:34 PM|
|oldred||That setup may have worked somewhat but you are lucky you didn't get killed with that tank! Man I just can't believe people do stuff like this, have you got any idea at all just how much damage a ruptured 60 gallon tank can do? A WATER tank is NOT suitable to use for air or any other pressurized gas storage, never ever use a water tank for an air tank!|
|12-02-2011 04:19 PM|
One of my 1st compressors
was run buy a 4 Hp gasoline engine and the compressor was off a large freezer from the 1950's and all i had on it was 2 100lb blow off valves and let it run continuously when i was using it. it ran all my air tools plus paint when i added a water filter from sears. Costs here was nill i had the engine and the freezer compressor was rescued from our local dump. the tank was a water tank about 60 gallon galvanized one.
|12-02-2011 04:02 PM|
|oldred||You will be rewarded for doing your homework! Most homebuilt compressors either don't perform well or break something in short order or both because the builder does not bother with the details like you have but I predict yours is going to work out just fine, keep us posted.|
|12-02-2011 01:00 PM|
I found a winner. Northern Tools Northstar 45929 pump. rated for gasoline powered compressors and gives a 5hp requirement for gas engines, or 3hp for electric. Also, they use the identical pump in 1 of there Northstar branded compressors, and the parts breakdown for that compressor is in the pump manual.. 1570 max rpm, 700 min. but with the 11" pump pulley and 4.5" engine pulley it'll spin 1472 RPM, 736 RPM at idle. So it's perfect. All pump parts are available too.
8.2 CFM@ 90 PSI and I may order the tank for the compressor as a replacement part out of the manual. It holds the mounting locations for the pump, and being it's GX powered, my clone will bolt up directly
|12-02-2011 09:48 AM|
I was only guessing and the thing may not be any different than a pump for the electric compressor, I can't help but think it probably is modified or possibly they just keep the idle RPM up to the minimum pump RPM? From what limited experience I have with these little compressors I have found them to be a series of compromises in design but for their intended purpose and for what they cost that is to be expected and usually not much of a problem. Obviously one of these compressors would not last long in everyday use like the industrial units but then they were never intended for that purpose. Building one from parts is certainly do-able and can result in a usable compressor but getting it fine tuned to work efficiently can be an exercise in futility, most home built gas compressors I have seen usually were fairly wasteful and consumed a lot more fuel than a factory built properly tuned design that provided the same amount of air. Lots of guess work, trial/error and just simply having to use what's available makes it darn near impossible to even get close to the efficiency of a factory engineered unit but I bet that HF compressor would be little to no better than a well thought out home made outfit.
|12-02-2011 09:31 AM|
Ya might look around for a new or used comm. construction unit with a gas engine rather than elect. Just change the engine out !!
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