Air Compressor build

[marineengineer]

I am young and Starting a tool Collection i have got all the Basics but want to build an Air compressor as a project/ learning experience. I can Fab/ machine anything necessary but i don't know the specifics to build to ex. what CFM, tank size, hp to build. I know that i want a 240V motor but besides that i am confused as to what to look for. I want to keep this cheap as im a marine Engineering student and will get parts from scrap yard/ craigslist. I want this compressor to run a sandblaster/ impact gun and any tool i buy in the future.

 

[PT Doc]

You want to build a compressor from scratch by piecing parts together from a scrap yard. You will not find all you need. If you try to build a one with new parts you would likely spend 3x the cost of a new unit. If you need specs, then find a 7.5 hp 80 gal 2 stage and go from there. Good luck. Please keep us posted on the progress and take photos. Be safe.

 

[JASTECH]

If I may, There have been thought running about in my knoggin.
>
Used a propane tank.
A/C Compressor from 1t
Used 5hp 184t 240vac motor
Find proper pully for cfm needed
>
Is this possible?

 

[CNGsaves]

Lots of people have built their own compressor from piece-meal parts.

Biggest risk to your safety is the TANK . . . do you plan on using an old tank from a different compressor, or Trying to weld up your own tank?? If you're trying your first knack at welding and it's a 175psi air compressor tank, I sure do NOT recommend it. Manufactures have strict product liability for their tanks so they build them right, and actually overbuild them to handle much higher pressure than air compressor can ever produce.

Otherwise, bolting together a mixed bag of parts should be fine. You'll just need to match up regulator, cylinder capacity, motor capacity, tank capacity, pulley speed, etc. Good luck, but do it safely.

 

[marineengineer]

The welding on a tank would be fine i am a certified welder and have looked at different tanks i was thinking id go with an 80 gallon old propane tank..... air it out for a while and get a compressor head from craigslist maybe and rebuild it if needed. the motor id just get whatever i can find and use that until i find the exact one that i need. Its not so much that i don't want to buy a compressor off the shelf it is i just want the challenge to make one. Has anyone used floor board radiator piping with fins as a inter cooler between the stages? are all Pressure cut out switches the same? could i find an old one from a nail gun compressor and set the pressure cut out switch to work on the one that i build?

 

[bsaint]

The important component of your compressor is your motor. I generally build my compressor around my motor.

 

[Alchymist]

The welding on a tank would be fine i am a certified welder and have looked at different tanks i was thinking id go with an 80 gallon old propane tank..... air it out for a while and get a compressor head from craigslist maybe and rebuild it if needed. the motor id just get whatever i can find and use that until i find the exact one that i need. Its not so much that i don't want to buy a compressor off the shelf it is i just want the challenge to make one. Has anyone used floor board radiator piping with fins as a inter cooler between the stages? are all Pressure cut out switches the same? could i find an old one from a nail gun compressor and set the pressure cut out switch to work on the one that i build?

Most of the HW pipe radiators i have seen are made from thinwall copper tubing with aluminum fins. I doubt the tubing would take much pressure. HW systems don't run very high pressures.

 

[Trey T]

If you're a student and starting, don't go overboard and get anything larger than a 30gal 6CFM @ 90psi - 110V.

School first, hobby second!

 

[mark52621]

A compressor is one of the few tools where it pays to spend more money up front. A cheap compressor will frustrate you every time you use it until you replace it with something better. You can't have enough air. Buy a 7.5 hp 2 stage the highest quality you can afford.

If you don't want to buy new search craigslist until you find a quincy qr. Quincy is the best made and has the best service.

Never use a non certified tank. Never wield up pin holes in the tank just replace it. If you don't believe me look up exploding air tank on google. My favorite is the one that went through the garage and ended on the roof.

 

[CNGsaves]

For MarineEngineer's safety, thought I'd include the terrific SAFETY thread that graphically shows what can and DOES happen if a pressure vessel explodes. See at:
http://www.garagejournal.com/forum/showthread.php?t=86685&page=2

Main thread is about small horizontal tank compressor (old with rust on bottom of tank) blew up and nearly tore a guy's left hand off, broke his leg in multiple places, along with other injuries (see pics as he's lucky to still be alive). Another example is casting failure on a big compressor cylinder that blew out and killed a guy.

I have to say using a Propane tank for air compressor use is BAD idea. Propane tanks were NOT designed to be used for air compressor purposes. Key factor on pressure vessels (ie air compressor tanks) is clearly stamped on tag on tank - - - MAWP which is Maximum Allowed Working Pressure. Tank manufactures build in safety factor well beyond the MAWP.

Have to say idea of building own compressor is NOT wise. Way too many things that can go wrong!

 

[onewaydave]

If you're a student and starting, don't go overboard and get anything larger than a 30gal 6CFM @ 90psi - 110V.

School first, hobby second!

I kinda identify with this, but have had toooo many projects for my day job my whole life.

Here is how I intrepret the question.

1. A compressor is just a pump. There are many examples of using old internal combustion engines for compressor pumps from lawn mower to v-8s. You just have to figure out how to plumb it.

2. What you want and what you need, well.... Figure what you want to use it for in the immediate future and build to that. If you are going to air up tires on your bicycle versus sand blasting and running 6 air tools for 8 hours a day. You need to figure; a) how much air do you need in cfm, and at what pressure, b)how much motor do you need to run those specs on the compressor, c)configure the plumbing and electrical. Oh yeah, before all that figure what color you want to paint it (real important).

3. Tanks are relatively cheap so I've never bothered with the welding issue. I have 3 patched-together-home-made-designed on the farm. One new tank and 2 of unknown age that just won't die.

4. If you don't make/repurpose your own compressor, educate yourself on the "good" oldies and keep an eye out. They come up at auction and classifieds all the time.

Dave.

 

[marineengineer]

got an old quincy compressor head on the side of the road free on saturday its a model 214 looks solid i called quincy and they said it can handle a 5 hp so thats what im looking for next. Also i think a 100 gallon tank will be a good reciever will be good. And the whole thing is getting plumbed in with schedule 80 galvanized 2in pipe so that will add another 50 gallons. ive got to figure out water/moisture drops stilll but its a start.

 

[mark52621]

If you live in farm country check out local auctions for electric motors. I've bought 5 hp motors for $50. Turn the shaft by hand to feel if the bearings are dry or rough. If you're lucky it will work. If not then send them to a electric repair shop to see if it is fixable.

Call quince and tell them your pump and what psi your going to run and they will tell you what size pulley you need on the motor.