Air compressor expansion tank build or purchase?

Any questions about tools or supplies. Post your compressor/gun questions here.



Settled In
Posts: 18
Joined: Sat Sep 17, 2011 8:36 pm

Country:
USA
PostPosted: Mon May 09, 2022 12:57 am
Does anyone sell an expansion tank for air compressor pneumatic system, or I have to build one myself? I'm assuming I have to build one, but asking just in case. My piping is at 1 inch anyway, and most tanks are like 3/8 at best. And another more hardcore question: Instead of building a 5 or 10 gallon expansion tank, why not add another 60 gallon tank and enjoy more air at the same time. Did anyone did that?

I'm currently designing my pneumatic system for painting, air tools, and sand blasting. I have that famous Harbor Freight 60 gallon 5HP compressor, which btw is lovely, but not big enough in terms of air storage . Adding another 60 gallon tank would help. I stop my work whenever my compressor kicks in already, so adding another tank would not really put too much pressure on the compressor. Been reading the forum on pneumatic systems and most of you have the copper loops with expansion tanks, but no one really has a bigger tank instead?

Any drawbacks you can think off?

User avatar

Board Moderator
Posts: 9070
Joined: Fri Oct 20, 2006 12:40 pm
Location: ARIZONA
PostPosted: Mon May 09, 2022 10:23 am
Try doing a search on this. I remember it being discussed at length a while back.
1968 Coronet R/T


ACTS 16:31



Fully Engaged
Posts: 106
Joined: Fri Aug 27, 2004 10:18 am
PostPosted: Mon May 09, 2022 10:32 am
You need to focus on air delivery. What is the CFM of your compressor? HP or Amps or anything else is just hand waving by the manufacturer. Unless your really going to use some compressed air 1" lines are WAY overkill!

Are you a commercial shop? If so your compressor is just too small. Tanks get bigger as the CFM output increases. That's why 5HP and 7.5HP units usually have 80 gallon tanks. Cheaper lower output units will have a 60 gallon tank.

Yes with 1" lines that 3/8" outlet is small but again what amount of air are you going to use? If you look at flow charts (See Below) that 1" starts around 25 cfm so your way oversized for that compressor.
Sorry terrible forum software again and it won't allow me to post a chart?

Here is the link to the chart I am talking about.
https://www.about-air-compressors.com/cfm-pipe-size-chart/
.
.
.



Settled In
Posts: 18
Joined: Sat Sep 17, 2011 8:36 pm

Country:
USA
PostPosted: Mon May 09, 2022 12:22 pm
clubairth wrote: HP or Amps or anything else is just hand waving by the manufacturer. Unless your really going to use some compressed air 1" lines are WAY overkill!

Here is the link to the chart I am talking about.
https://www.about-air-compressors.com/cfm-pipe-size-chart/
.


I have the famous CENTRAL PNEUMATIC 60 gallon 5 HP 165 PSI Two Stage Air Compressor at 15.8 CFM bought long ago when it was using the same exact parts that are used in top dollar compressors. I'm not a commercial shop and never will. I do motorcycles, cars and furniture build and restoration for myself only. I'm new to painting, but I'm not new to anything else. Almost all 5HP compressors put about the same CFM. That's just physics plus minus. Is the compressor too small for me? You might be right, but I need to work with what I have.

Yes, 1" inch may sound overkill for 15.8 CFM, I agree, but it does not work like that. It's more complicated. Distance in a smaller hose drops CFM like a rock, hence I'm overbuilding, and maybe one day I will get a bigger compressor or build my own. I am running sand blasting machine that I redesigned around a different concept than what you buy out there. I need tons of air. Anything less than 1" and I have too much drop off in CFM at the blasting machine. And since my compressor is working hard I may as well use all it's air not 70%. Hence the 1" pipe. I just need some nice air expansion tank to do the hard work.



Settled In
Posts: 18
Joined: Sat Sep 17, 2011 8:36 pm

Country:
USA
PostPosted: Mon May 09, 2022 12:25 pm
'68 Coronet R/T wrote:Try doing a search on this. I remember it being discussed at length a while back.


I did read most posts about it and guys simply bought some Harbor F. tank and build something out of it. No other posts or anyone adding a full size tank, which is what I'm leaning towards.



Top Contributor
Posts: 5580
Joined: Tue Sep 16, 2008 1:17 pm
Location: Pahrump NV.
Country:
USA
PostPosted: Mon May 16, 2022 10:21 am
I run two expansion tanks that were made for the purpose they do help.
You could buy or build your own, After what I have seen with Air tank explosions on internet I would lean toward a mfg piece with coatings on the inside of tank that prevent rust.
Its old school Tech it works but The best is Refrigerated cooler prices have been coming down on them to where their in reach of Mortals now days.

I have seen some come up second hand used on Craigs list Ebay and such
Dennis Barnett
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.



Settled In
Posts: 18
Joined: Sat Sep 17, 2011 8:36 pm

Country:
USA
PostPosted: Mon Jun 27, 2022 11:27 pm
Doright wrote:I run two expansion tanks that were made for the purpose they do help.
You could buy or build your own, After what I have seen with Air tank explosions on internet I would lean toward a mfg piece with coatings on the inside of tank that prevent rust.
Its old school Tech it works but The best is Refrigerated cooler prices have been coming down on them to where their in reach of Mortals now days.

I have seen some come up second hand used on Craigs list Ebay and such


Yes, I have seen rust in my own tank when I opened it up this week, and I do worry about explosions especially that I sand blast close to the tank.

Anyway, I did more research and more work, and I came up with different conclusions:

1. Due to small current recession and some deflation (finally FED doing their job) I noticed I can buy a full blown used 60 gallon tank for $100, or a insanly big compressor for $800. I'm talking about 10 to 15 HP tank that puts close to 50 CFM. So I'm not going to be adding small expanion tank. I will add another full tank and have more air as well.

2. I abandoned all common ideas/theories/religions about air compressors and I built myself a rocket. I will post the entire idea here and "give back" once every part is tested and I run it for a month or two. I'll document and draw everything out. How one can take 5HP $750 Harbor Freight compressor and outperform a $5,000 machine. I made it so powerful I'm freighted whenever I use my air tools, or connect my hoses. The sheer volume of air is out of this world now. It took balls and tons of research, but it all makes common sense according to physics. No money (or little if you plan in advance) is required to improve.

3. I also put together a spray booth for $100 that has not been tried before. There were similar ideas, but mine became even simpler, cheap, and efficient. Anybody can build it.
I'll take pics and create a thread for that.

4. I also turned my Harbor Freight blaster into another rocket. I again abandoned what people did on YouTube and build something simpler and insanely powerful. Will document that as well in another thread.

User avatar

Top Contributor
Posts: 2098
Joined: Sun Dec 16, 2012 4:46 am
Location: Canberra
Country:
Australia
PostPosted: Tue Jun 28, 2022 1:17 am
This should be interesting. Is Einstein about to be toppled?
Chris



Settled In
Posts: 18
Joined: Sat Sep 17, 2011 8:36 pm

Country:
USA
PostPosted: Tue Jun 28, 2022 3:15 pm
NFT5 wrote:This should be interesting. Is Einstein about to be toppled?


No lol. He stole everything from Nic Tesla. I ain't steeling.

Return to Tools and Supplies

Who is online

Users browsing this forum: No registered users and 10 guests