Go Back   CLASS RACER FORUM > Class Racer Tech > Support Tech

Thread Tools Display Modes
Old 02-28-2018, 06:34 PM   #1
Join Date: Dec 2009
Location: Kingman, NW AZ. in the middle of the longest stretch of Route 66
Posts: 217
Likes: 0
Liked 0 Times in 0 Posts
Default air comp. ?

I want to build an air comp. just for sand blasting [I do a lot of it]. I have a 40 gal. tank and a 3 hp 240 V motor. a friend gave me a 2 stage pump. I am almost sure it needs rings and reed valves. it has no ID on it, so must be a China. looks to be a 3" 1st and a 2" 2nd with maybe a 2 1/4/1/2 stroke. fairly sizable, & a 14" flywheel. probably cost $100 for parts and a lot of time.
I can get a brand new Harbor Ft pump, 2 cyl, 145 PSI [uses a 3 hp motor] for $112 + tax, and ready to put on.
my question is, what is the benefit of a 2 stage over a 2 cyl. single stage?
Thanks Rod in AZ
rod is offline   Reply With Quote
Old 03-01-2018, 11:17 AM   #2
Lew Silverman
VIP Member
Lew Silverman's Avatar
Join Date: Mar 2010
Location: Newport News, VA
Posts: 1,352
Likes: 1
Liked 2 Times in 2 Posts
Default Re: air comp. ?

Do you know how many CFM the sand-blaster requires to operate properly? That will give you the best idea when building an air compressor. You usually want a unit that is at least capable of providing 1.5 times the air volume your tool requires and a large enough tank to keep the pump from having to exceed its duty-cycle rating. The two-stage units most often have a higher pressure rating than the single-stage units do, but for tools that use a lot of air (like a sand-blaster) the SCFM ratings are much more important.

I see the pump you are talking about in the new Harbor Freight catalog that arrived this morning, but it doesn't list a SCFM rating. You'll need it to make a decision.

Good Luck!
Lew Silverman #2070
"The Wagon Master" N/SA
Lew Silverman is offline   Reply With Quote
Old 03-01-2018, 03:59 PM   #3
Junior Member
1matcoman's Avatar
Join Date: Jul 2008
Location: Deer Park, Texas
Posts: 82
Likes: 27
Liked 8 Times in 4 Posts
Default Re: air comp. ?

Originally Posted by rod View Post
my question is, what is the benefit of a 2 stage over a 2 cyl. single stage?
Rod, the 2 stage unit will be almost twice as efficient as a 2 cylinder single stage. Meaning that it will fill your needs in approximately 1/2 the time that the smaller unit will. The dual-stage forces air in to the tank on both the intake AND the exhaust stroke, whereas the single stage will only do so on the compression stroke. Keep in mind that a sand blaster uses ALOT of air volume, so don't cut any corners with your air compressor build (or purchase) if you are planning on using it for that.
1matcoman is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -5. The time now is 12:05 PM.

Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright © Class Racer.com. All Rights Reserved. Designated trademarks and brands are the property of their respective owners.Ad Management plugin by RedTyger