Jump to content
HybridZ

purchasing an air compressor


Guest DRK

Recommended Posts

I have a 6hp Sears oilless compressor, and like everybody says, it is LOUD. Mine did crap out on me a month or so ago - the 'rings' gave out, and the compressor just couldn't get the pressure up to the shutoff point - if I had not been there to shut it off, it would have run like that forever.

 

I will say that the replacement parts were relatively cheap - an entire piston/rod/bearing/sleeve assembly cost about $30 as I recall. Also, it's all pretty modular - I was able to take it apart and replace both cylinders in about 15-20 minutes. ~$75 total.

 

That said, I would never buy an oil free compressor again. It was just quicker and cheaper to fix this one at this point.

Link to comment
Share on other sites

That is good to know about the pvc failing at 160psi. My buddy and I were shooting a 50cc Honda scooter piston out of his potato gun yesterday, and it is made from pvc pipe. It was the perfect diameter and slid right in with some grease. We were shooting it at a Chevy truck hood from about 40ft away, and could break the metal of the hood in about a 1/3 of a circle from where the top of the piston would hit it. We then filled the chamber with pure oxygen from the torch outfit, and it fired so explosively that a big flame shot out of the barrel, and the gun kicked back and flew out of my buddies hands. He missed the hood, and we could not find the piston after that. We had a blanket wrapped around the gun when we shot it with oxygen just in case it exploded. We were using Gumout carb cleaner as the propellant.

 

DK

Link to comment
Share on other sites

For what it is worth, I just bought a Compressor from Harbor Freight. It is a new one they just started carring from Chicago Pneumatic. So far it is great and runs all my tools without much strain. It is just as loud as any thing else, all compressors are annoying in my mind. My board sander works good, which is my highest strain tool and used to not work at all on my last compressor. I have been using a Cambell Hausfield nailing comressor since my 20 year old craftsman got ripped off. I was going to buy another craftsman until I saw this deal. I could not resist the price at 149 bucks. 4 1/2 horsepower oiled, with a 29 gallon upright tank. I think it is something like 7cfm @ 90psi, but I could be wrong. As for the oiled vs non oiled thing, I have no clue. My neighbor, a hot rod builder, swears that oiled is the only way to go. Seemed like good advise since his compressor is going on twenty something years.

Link to comment
Share on other sites

Guest livewire23

I work at sears (I actually sell craftsman tools) and get a bit of a discount. Are the oil-less craftsmans really so bad that I should go to a husky even if Im paying a lot more for it? Im thinking around 6hp 33 gallon vertical tank style compressors. I want to be able to run a spray gun, impact hammer and some other basic tools.

cheers

Link to comment
Share on other sites

I would recommend getting a compressor that you will be happy with and that will fill your needs for many years. Somthing that would run a die grinder without much trouble. You may decide down the road that a spray gun and impact is not enough and that you would like to gasket match or polish the bowls of some heads.

Doesn`t sears sell ANY belt driven, and oiled compressors any more?

If all else fails, get a copy of some regional classifieds and see if you can find a used one. For 250.00 I bought my 80 gal. 5hp 2 stage compressor from a tool and die shop that was building a new shop and wanted all NEW compressors. It works as well as the day they bought it, and has full service and maintanance records from the day it was installed

Why buy new when used will do the same job? ;)

Link to comment
Share on other sites

  • 2 weeks later...

After reading everyone's advice, I bought a Husky 5hp 26gal vertical tank oil lubricated compressor today from Home Depot. It was $370. After a nice 50ft hose, an accessory kit, some extra fittings, and some oil, the total was $464 out the door including tax. I was surprised at how quiet it runs. It cuts off at 135psi, and cuts on at 95. The motor can be wired for 240 volts, but It comes ready for 115v. I think it is a good unit for my situation.

 

Danny

Link to comment
Share on other sites

Guest livewire23

I think I'll try and pick up this unit from ebay. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=22662&item=2086546577 Really, I dont want to sink some $500 on a compressor. I decided to forget about painting, and limit the compressor to powering impact tools. Sander, grinder, impact wrench, the basics... Im still looking for a decent oiled air compressor for around $200 or under. Haha, maybe its a bit of a long shot.

 

or how about this one? its not a brand i recognise, but it seems to pack a good CFM, and its not oil-free. Should I be suspicious?

http://www.homier.com/default.asp?page=categories.asp?dept=1

Link to comment
Share on other sites

If I remember right, Homier has been through here doing one day sales in a rented hall (off a semi)& had typical import stuff.

 

Your link didn't specify any one compressor. I only saw one that is belt driven... a 5 horse unit putting out under 7 CFM; not much air for 5HP. (I have a 5HP two stage that does around 17 CFM. I really like 2 stage as my air tools function well throughout the pressure range... They seemed to get a little tired before my old single stage started pumping up again).

Link to comment
Share on other sites

Guest livewire23

well, in the end, like an idiot, I got this real cheap compressor from home depot. Came with a complete tool kit and everything for around $300... It only took me about an hour to realize it was too weak to power the tools it came with, and it went right beck to the depot. I went to work and got a good deal on a craftsman 6hp 30 gallon tank, which has worked just fine... A bit loud but real nice. If anyone has success building a sound booth for their compressors, please inform me. I dont do woodwork much, so i might be willing to just buy one off of somebody.

Link to comment
Share on other sites

The 1/2 inch Shedule 40 pipe I used to plumb my garage is rated at 600 PSI. Says so right on the side of the pipe. I also have some 1/2 inch "Silver Line" PVC that is only rated at 315 PSI, but I didn't use that. I have seen other types of PVC that state very clearly "not for pressure".

 

Perhaps is depends on what type of PVC you use? Would seem that a 600 PSI rating should provide a sufficient margin on a 125 PSI compressor. Why would compressed air be anymore stressful to the piping than water?

 

Can anyone provide more details on exploding PVC? Kinda got me worried.

Link to comment
Share on other sites

Guest Anonymous

Jim Powers.. I have seen shops plumbed for years with pvc schedule 40 without a problem.. I have a 5 HP 60 gallon vertical tank 2 stage 220 volt that I reduced the pulley so the compressor would not reach as high a rpm.(And reduce wear).The cheap thing was built with an oversize pulley to wear out prematurely, Lately the compressor has a little trouble running with air tools in constant use...For serious air tool use a two stage compressor is the way to go with 6 hp or better."Nail guns" require little air to operate while grinders and such cannot get enough air.

Link to comment
Share on other sites

Piss. Answered my own question

 

http://www.osha-slc.gov/dts/hib/hib_data/hib19880520.html

 

Just one excerpt:

 

The main problem with using PVC pipe and fittings for compressed gas is not that it spontaneously explodes but that PVC is a brittle material that can be broken or shattered with external force unless properly protected. Compressed gasses can be best described as being analogous to a coiled spring. When a PVC pipe or fitting fails when under stress from compressed gas it literally explodes like a bomb, sending shards of plastic flying several feet in all directions. Liquids, on the other hand, being compressed by only 1/10th of 1% contain very little stored energy. When pressurized systems with liquids fail, the energy is dissipated very quickly, thereby creating a much lower potential for hazard.
They say it can be used as long as it is encased in something else (like buried). They go further to say it is illegal in many states. No big deal to me but a definite lawsuit issue to anyone running a commercial shop.
Link to comment
Share on other sites

Jim- the military makes land mines out of plastic and I've seen the resulting shards- they look like chipped flint or obsidian. NO WAY would I set up a plastic air system... copper may conceivably split some day and let all the air out, but at least it won't throw razor blades at me.

 

Was this .02 or a nickel's worth?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...