Help with Custom Tank

Installation Help & Advice Onboard Air & Air Suspension
1

Well, I bought an 8.5 gallon from HB for my K5, but I’m rethinking.
I bought 2 compressors from them also and could technically use 10 gallons.

It’s going in the front of my truck bed, so I would like to save space.
The 8.5 gallon is 10”+ in diameter and I think I could do it with stacked 6 inchers.

Materials & tools are not an issue, but I have never built a pressure vessel.
I’m leaning towards aluminum for weight, rust resistance, & cool factor.

So for lack of experience I tend to overbuild and I was thinking 6” x 1/4” wall aluminum tubing.
And 1/4” thick flat endcaps. I should be able to pour the heat to it & not worry. TIG welded.

So does anybody have any suggestions / experience?
I know a tank usually has “rolled heads” for the ends, but since this is so small (5.5” i.d.) I figured flat would be ok.
How would I know if it’s good for 200psi?

When I get farther, I’ll post a CAD drawing.
Thanks a lot!

2

http://trainhornforums.com/showthread.php?t=1216&highlight=civic&page=2

He made his own tank and used a Hydrostatic pressure test to test it up to 240…

3

Thanks Twist. I did a search but that one didn’t come up.

Here’s a general idea of what I’m thinking.

Let me know what you all think.

4

If you have never manufactured a tank… I would HIGHLY suggest staying away from it… and if you decide to go ahead and build it keep others saftey in mind and dont take it around any one…

5

You may be able to take it to a machinist and have them do it for you?.. just a thought

6

I totally agree - safety first. Probably have to pony up & have the thing tested. Maybe at a boiler repair shop or something.

Thank you for the concern. Let me give a little background. I am a mechanical designer/drafter for a company that makes food processing equipment out of stainless steel. Been here 16 years next Tuesday so I am aware what it takes to make something. Anyway, I have access to our machine shop, sheet metal shop, CNC plasma / punch presses, Water Jet, etc…you get the idea.

One nice thing we have is a rotisserie for welding / polishing / whatever. Once the welder is set and the rotisserie speed is set, you make one MIG pass around the endcaps and end up with basically a robot weld.

I used it for my 8.8 axle housing for my drag Mustang.

I did this side first. The other side looks even better.

So I can make all the parts proper with no gaps for welding. I can at least tack everything together & weld the endcaps. I may have one of our good welders do the bungs and connection pipes. I can weld the external brackets.

When it’s all done I’ll have the thing tested.

7

thats better that you have that knowledge would be kool to have a custom tank but yeah definitely have it tested :wink:

8

Tanks typically have rounded ends for a reason. It would be far cheaper in tooling to have flat ends, but rounded ones hold high pressure better. This could be because condensate can’t sit on a rounded surface - but it can sit in a corner if you built a tank with flat ends. In time, the metal would deteriorate at these junctions, and weaken the vessel. If you are not experienced in building pressure vessels, I’d steer clear of this project.

9

Isn’t the rounded ends on a pressure vessel actually a design feature to strengthen the tank allowing it to hold higher pressures?

EDIT - Sorry, I obviously can’t read as Lance said the same thing.

10

Yeah, I’ve been looking at possibly buying actual tank heads. It has less to do with condensate in the corner & most everything to do with the physics of the stresses involved. Rounded ends keep all the stresses equal and in tension. Sharp corners get weird with some stresses in compression.

I guess I was hoping that since we’re only talking about a 5.50" I.D. (23.76 sq inches) that I could get away with flat. If you look at the drawing, I set the caps into the tube 1/4" to get a big fillet weld. I could go thicker on the endcaps and even bevel for the weld. We happen to have some 3/8" in the scrap bin right now. 1/2" works too.

I sure have found some ineresting stuff searching the web! Bumper tanks & frame tanks… And some D-Bag trying to make a 24" x 36" x 4" FLAT tank for his spare tire well. Talk about a pillow / bomb!

Anyway, ran across some comments that it needs to be tested to 3.5x safety factor for DOT.

I estimate $232 in materials. Round tank heads would likely double it. We’ll see what welding & testing costs, but if this thing approaches $1000 - it’s dead.

11

How about buy two different sized tanks. and mount them on top of each other somehow…

12

That is an option. Firestone makes a 5 gal tank that is 8" dia x 33" long.
I’m also trying not to drill a crap load of mounting holes in the truck.
If I go custom there would only be 4 mounting holes for the tank & none for the compressors.
Plus I can put the 9 ports exactly where I want them.

I’m not ruling out the Firestone tanks. Or any other long/skinny 5 gallon tanks that anybody knows of. Or even a long/skinny 10 gallon tank. The available space is 64".

13

I would highly advise against building a pressure vessel if you have no experience in that field. If you must do this, I would suggest getting in contact with an engineer in a boiler shop and get recommendations as to what materials would be safe to use. I personally haven’t see any pressure vessels that were made out of aluminum and there is probably one reason for this, cost. It probably could be done but I think that the requirements to make a tank out of aluminum would be double or triple that of what would be required to make the same tank out of stainless or carbon steel.

14

usually high pressure c02 tanks are made out of aluminum but they are pressed out of one solid block of aluminum and typicly hold around 1500 psi

15

I will be making a few phonecalls. I have a few numbers for inspection / testing / welding.

I have seen lots of aluminum tanks for sale. Firestone, Air-Zenith, Trick Tank, etc…
Air-Ride Technologies makes 1 & they tout the weight as only 8 lbs - so I know it isn’t very thick. Harbor Freight even has portable 7 gallon 200 psi alum tanks that weigh 10 lbs.

So aluminum isn’t the issue especially if I use a smaller diameter & 1/4" thick. Where I’m going to run into problems is the flat ends and maybe non spec material. Meaning I do not have mill spec sheets for the material.

Anyway, all I can do is see what they have to say.

Why doesn’t anybody make a 10 gallon tank? Even some of the ‘5 gallon’ tanks I’m finding aren’t 5 gallons. 7" x 28"…nope

16

Doesn’t Hornblasters have long skinny tanks or try some tank manufacturers? I wouldn’t try building my own.

17

Currently searching for & contacting tank manufacturers.

Optimum 10 gal tank for me is about 7" diameter X 63" long.

Why doesn’t anybody make a 10 gallon? Compressors are rated for 5 gal and lots of people have 2 compressors. I don’t get it.

18

Manchester makes many different tanks which can be seen in a McMaster-Carr catalog. I don’t know if they make one in the dimensions you’re looking for. You might try searching for Manchester tanks online.

You don’t need 10 gallons or 2 compressors, just an Oasis XD3000 and small tank. It will fit your vehicle but maybe not your budget and that’s why we all have credit cards.

19

Thanks for the heads up for Manchester. I’ll check them out - I know McMaster didn’t have what I wanted.

I hear ya on the XD… I even have the power to run it with dual alternators & 3 batteries. ha ha But I already bought my compressors.

I now have a CAD drawing out for the first quote. Hope I don’t choke.

20

Here’s the basic layout. (4) 1/2" ports and (5) 1/4" ports

The drawings I sent out are fully dimensioned and have everything unbolted for clarity.
The guy quoting this thing wants one for his truck too…lol
Would anybody else be interested in a 10 gallon tank like this?
With or without compressor brackets?

Let me know what you guys think-