Air Compressor

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MaineVette
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Air Compressor

Post by MaineVette »

Currently I'm using a Craftsman air compressor I purchased from Sears many years ago. Specifically, it's a 30 gallon unit with a motor rated at 6HP peak / 2HP running. The compressor can put out 6.4 scfm (standard cubic feet per minute) @ 90 psi.

I've actually found this compressor to be undersided for certain tasks. For instance, it's barely big enough (and probably a bit undersized) for continuous use of air tools such as die grinders and DA sanders. For sandblasting it's totally and completely undersized. :ack:

Obviously buying a new compressor big enough to power a sandblaster on it's own did not seem practical (the cost of the compressor would be significant). Instead, I borrowed a second compressor from a friend and then used a tee fitting to combine the feeds from both compressors. The result was an air supply capable of providing about 12 scfm @ 90 psi which worked great for sandblasting. Together the units were capable of actually maintaining between 60 and 80 psi during continous sandblasting (depending on the tip size). By combining these units I was able to triple, or perhaps even quadruple, my sandblasting progress. The difference was night and day, and it sure beat buying another compressor!

For all my other tasks this compressor has worked well and I haven't felt the need to purchase another one. However, when this one does die I expect I'll purchase a new unit that's a bit larger.
Someday I'll finally be able to drive my Vette, but for now I'll just admire all the pieces... :willy:

Track my progress at The Corvette Restoration Page http://www.corvette-restoration.com
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nwav8tor
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Tell us about your Corvette: 1971 Coupe that's been in the family since new. Was "stored" in a shed in New England for 22 years. Even though I have limited knowledge and experience, I'm SLOWLY doing a body off restoration. Standby for many questions!
Location: Spokane, WA

Re: Air Compressor

Post by nwav8tor »

Some questions...

1st - Do you recommend getting a single stage compressor or one with two stages? I heard that single stages are MUCH louder than dual stages and that could be a factor in my neighborhood.

2nd - What are the pros and cons of oil lubricated compressors and the oil-less designs? Can an oil-less one actually handle the needs of restoring a vette?

3rd - I'm looking at a new 90# capacity pressurized Abrasive Blaster with 8ft hose, 2 nossles, water trap, pressure gauge and hood requiring 6cfm @ 125psi for $100. Seems like a good price, but is it practical for the restoration?

4th - Do I need to also get an air-powered impact wrench for the restoration? If so, is a 1/2" drive with 250 ft/lbs of torque, 7000rpm, 5/8" bolt capability requiring 5cfm @ 90 psi adaquate? Should I get normal or deep impact sockets or will I need both sets?

Thanks for help & insights.

Paul
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MaineVette
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Tell us about your Corvette: 1971 Coupe, restoration in progress.
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Re: Air Compressor

Post by MaineVette »

Well, first off I have some sad news. My trusty Craftsman compressor has driven its last impact wrench. The motor shorted out and died a few weeks back and the replacement motor costs almost as much as a new one. :eek: I guess now I have an extra 30 gallon tank that I can use for whatever.

Now to your questions...
nwav8tor wrote: 1st - Do you recommend getting a single stage compressor or one with two stages? I heard that single stages are MUCH louder than dual stages and that could be a factor in my neighborhood.
The answer really depends on your needs. Most compressors you buy these days from Lowes, Sears, or other similar stores are all single stage compressors. In my opinion the most significant difference is in the amount of pressure that can be developed. Most homeowners and shadetree mechanics run power tools that work well with about 100psi of pressure. Therefore, they don't have much need for a compressor that can develop 200psi and it's not worth it to spend the extra money. Granted, the higher pressure allows you to store more air which means the compressor runs less often, but the same thing can be achieved by buying a unit wiht a larger tank.

I'm not aware of any differences with the noise level. My old craftsman compressor was a bit on the loud side - probably comparable to a riding lawn mower with the throttle pulled all the way to down to the idle position. So yes it was a bit noisy but I wouldn't worry about your neighbors calling the cops on you (assuming you've got it in your garage and not in teh back yard).

Here's some more info: http://www.grainger.com/production/info ... ressor.htm
nwav8tor wrote: 2nd - What are the pros and cons of oil lubricated compressors and the oil-less designs? Can an oil-less one actually handle the needs of restoring a vette?
Well, an oil lubricated compressor will definitely last longer and is much better suited to continuous-use applications (such as sandblasting) since the oil lubrication helps prevent overheating. My old non-lubricated compressor lasted about 5 years before the motor died, but it ran well up until that point. If you plan to do a lot of sangblasting I'd spring for an oil-lubricated unit since it should hold up better for you. I have my eye on a nice looking 240v Ingersol Rand oil lubricated unit that runs about $500 but I'm not sure I can swing the cost (donations are welcome! :D ).
nwav8tor wrote: 3rd - I'm looking at a new 90# capacity pressurized Abrasive Blaster with 8ft hose, 2 nossles, water trap, pressure gauge and hood requiring 6cfm @ 125psi for $100. Seems like a good price, but is it practical for the restoration?
Sounds comparable to what I bought. My sandblaster was bought on E-bay for about $100 and I did my entire chassis, suspension components, etc with it. It worked great for that purpose. By the end some of the components (hoses, valves, etc) were leaking or inoperable due to the wear of the grit going through them, but I think that would be expected with any unit. If I were to do it again, I'd buy the same sandblaster again. Just be sure to buy lots of extra tips - I couldn't find any locally and you really go through them fast (for me 1 tip lasted about 1 hour until it got so worn out and passed so much air that my compressor couldn't develop good pressure).
nwav8tor wrote: 4th - Do I need to also get an air-powered impact wrench for the restoration? If so, is a 1/2" drive with 250 ft/lbs of torque, 7000rpm, 5/8" bolt capability requiring 5cfm @ 90 psi adaquate? Should I get normal or deep impact sockets or will I need both sets?
Definitely get an impact wrench! 250 ft/lbs should be fine but if you can find one that has higher torque (especially in the reverse setting), that would be a bit better. Definitely go for a 1/2" drive. You shouldn't need to get deep impact sockets, normal sockets should suffice. I actually use my normal Craftsman non-impact sockets in my impact wrench and they hold up well (never had any problems). When you get the impact wrench try to get one that has multiple forward (tighten) settings so you can avoid over-torquing bolts. I have a middle-of-the road Craftsman model and it works great for me.

Well, hope this helps. Good luck and have fun buying your new tools! :cheers:
Someday I'll finally be able to drive my Vette, but for now I'll just admire all the pieces... :willy:

Track my progress at The Corvette Restoration Page http://www.corvette-restoration.com
JE Caudle
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Tell us about your Corvette: My car is a time worn L-82 4 Speed Silver Anniversary.
The car has been lowered about 2 inches and the L-82
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Location: Fenwick Mt., West Virginia

Re: Air Compressor

Post by JE Caudle »

I know this post is old. Hopefully someone will find it useful.

I have a two stage 80 gal. compressor. It delivers 20 cfm @ 90 psi
and 9 cfm @ 175 psi. I think I paid $850.00 for it. I choose this size
because it could keep up with my sand blaster and sand blasting cabinet.
You could connect an open 3/8" line and never run the tank out of air.

The compressor is connected to a good dryer. The dryer is then connected to a 2" manifold
which runs along 3 walls of the shop. The manifold has 3/4"X2' drip tubes every 10' or so.
They act as the last defense against moisture in the air line. They can be drained as needed.
There are quick disconnects about every 10'. This allows the usage of short air hoses which
in turn keep me from walking on or tripping over them. Hoses stretched a cross the shop are a
thing of the past. As I see it, the only thing I could have done better would have been to use hose
reels in the ceiling.

Compressors in general are loud! Mine is real loud. I need to build an insulated closet around it
so that I can hear the radio or a gun shot while it is running. :eek:
Gods Speed,

HillBilly John

Does it make me go faster or stick to the ground better?
If not I'm sure I don't need it...
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MaineVette
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Re: Air Compressor

Post by MaineVette »

JE Caudle wrote:I know this post is old. Hopefully someone will find it useful.

I have a two stage 80 gal. compressor. It delivers 20 cfm @ 90 psi
and 9 cfm @ 175 psi. I think I paid $850.00 for it. I choose this size
because it could keep up with my sand blaster and sand blasting cabinet.
You could connect an open 3/8" line and never run the tank out of air.

The compressor is connected to a good dryer. The dryer is then connected to a 2" manifold
which runs along 3 walls of the shop. The manifold has 3/4"X2' drip tubes every 10' or so.
They act as the last defense against moisture in the air line. They can be drained as needed.
There are quick disconnects about every 10'. This allows the usage of short air hoses which
in turn keep me from walking on or tripping over them. Hoses stretched a cross the shop are a
thing of the past. As I see it, the only thing I could have done better would have been to use hose
reels in the ceiling.

Compressors in general are loud! Mine is real loud. I need to build an insulated closet around it
so that I can hear the radio or a gun shot while it is running. :eek:
Dang, that's quite the setup! I wish mine was set up that way - just haven't take the time yet. Next on my list is to install a few hose reels to help keep things a bit neater.
Someday I'll finally be able to drive my Vette, but for now I'll just admire all the pieces... :willy:

Track my progress at The Corvette Restoration Page http://www.corvette-restoration.com
JE Caudle
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Posts: 10
Joined: Jan 23rd, 2011 1:13 am
Tell us about your Corvette: My car is a time worn L-82 4 Speed Silver Anniversary.
The car has been lowered about 2 inches and the L-82
has been replaced by a ZZ430.
Location: Fenwick Mt., West Virginia

Re: Air Compressor

Post by JE Caudle »

While your getting your reels for the air hoses you may want to think about overhead reels for
extension cords. If it's on the floor I'm going to trip over it or run into it with the creeper. :ack:
Gods Speed,

HillBilly John

Does it make me go faster or stick to the ground better?
If not I'm sure I don't need it...
manishapi
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Re: Air Compressor

Post by manishapi »

Could you tell me more … I would love to explore.
[url=http://www.toolsmark.com/air-compressors_c1.aspx]Air Compressors[/url]
JE Caudle
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Posts: 10
Joined: Jan 23rd, 2011 1:13 am
Tell us about your Corvette: My car is a time worn L-82 4 Speed Silver Anniversary.
The car has been lowered about 2 inches and the L-82
has been replaced by a ZZ430.
Location: Fenwick Mt., West Virginia

Re: Air Compressor

Post by JE Caudle »

manishapi wrote:Could you tell me more … I would love to explore.
Ask a question and I will try to provide the answer...
Gods Speed,

HillBilly John

Does it make me go faster or stick to the ground better?
If not I'm sure I don't need it...
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