Best rust desolving product?

Status
Not open for further replies.
S

SecondMonkey

Joined
Oct 9, 2007
Messages
931
Location
OR
The air compressor system I have in my garage is a tangled mixture of several smaller tanks all plumbed together, with three different compressors. I tend to be lazy about draining water out of tanks, especially since I have so many. I've decided to paint the inside of each tank with Rustoleum "Heavy Rust" metal primer and then a coat of enamel on top.

Problem is, a couple of my tanks are already heavily rusted inside. Obviously, I can't just sand it off...so what would be the best liquid product I can pour in the tank to dissolve the rust? I know I've seen some in the past but can't remember any brand names....

PS - these rusted tanks are going to be hydrostatically tested to make sure they're still safe.
 
how do you get inside of a compressed air tank well enough to work and paint the surfaces?
 
Be very very careful.

Compressed gas vessels, particularly compressed air receivers are some of the most dangerous stuff out there.

A backyard pain shop in town years ago wanted to avoid the hassle of owning and registering an air receiver. So they ran large bore screwed pipe along the side wall, across the back wall, along the other side wall, back again and so forth until they had ample volume, but nothing technically that was a receiver.

Had lots of outlets too.
 
Originally Posted By: Shannow
Be very very careful.

Compressed gas vessels, particularly compressed air receivers are some of the most dangerous stuff out there.

A backyard pain shop in town years ago wanted to avoid the hassle of owning and registering an air receiver. So they ran large bore screwed pipe along the side wall, across the back wall, along the other side wall, back again and so forth until they had ample volume, but nothing technically that was a receiver.

Had lots of outlets too.


That's a clever bit of lateral thinking !

anything with a substantial % of phosphoric acid is needed to convert the iron oxide to an inert phosphate oxide.
 
PB Blaster is a great product, but it is more suited to penetrating and loosening bolts and such. Eastwood company has a few products that I have used in the past with good results. They also will not leave any oily residue behind. Its called Eastwood Rust Converter. Good luck!
 
Originally Posted By: JHZR2
how do you get inside of a compressed air tank well enough to work and paint the surfaces?

You can't, that's the problem.
wink.gif
That's why I need some sort of rust desolver, I'll just fill up the bottom of the tank with it, where the water normally sits, which is the only rusty part. Then, after I clean that out, I pour in some paint, slosh it around, and dump the excess back out.

Originally Posted By: Shannow
Be very very careful.

Compressed gas vessels, particularly compressed air receivers are some of the most dangerous stuff out there.

Yeah, that's why I'll be pressure testing them. I'm going to fill it partially with water and then pressurize to 150% of the operating pressure. I'll be doing this with a long air hose out in the middle of nowhere where I shoot my guns.
 
Originally Posted By: SecondMonkey
I'll be pressure testing them. I'm going to fill it partially with water and then pressurize to 150% of the operating pressure. I'll be doing this with a long air hose out in the middle of nowhere where I shoot my guns.


Really, half filling them with water, then air over the top doesn't make much difference than all air.

You could Jury Rig a system up with a master cylinder that would get you there all hydraulic.
 
"Really, half filling them with water, then air over the top doesn't make much difference than all air."

Not exactly true.

As we know, air is compressible, water is not, in common daily experience. But pressure is all equalizing. The ability to check for leaks is the same, but the severity of the explosion, should there be a rupture, is greatly diminished by using mostly water. Let me be detailed, so that it's clear what I'm stating.

Consider two seperate 10 gallon tanks of the same construction. One has 9 gallons of water and open to atmospheric pressure for the 10th gallon. The other has 1 gallon of water and 9 gallons of open atmospheric volume.

Now, pressurize both until tanks with air until they burst. Presumming the tanks were adequately made, and similar in materials and construction, it would be reasonable to expect they would explode at, or near, the same pressure. The tank with less air and more water will "explode" with less violence, because there was less compressed air by relative volume. The 1 gallon of compressed air, once released, will expand to much less volume at atmospheric pressure than the 9 gallons of released gas. In fact, it's basically a 9:1 ratio.

The best way to pressure test any vessle is with hydraulic pressure. But that's sometimes hard to do, given the expense and equipment needed. It's much easier to test with air, because it's abundant and free. So, the next best thing is to fill the vessel nearly to the top with a liquid (water; again cheap and plentiful), then pressurize the remaining volume with air.

In regard to the vessles, the RISK (probability) of explosion is the same because the pressures are the same, but the MAGNITUDE (size) of the explosion varies with the volume of the compressed gas in relation to total volume of the vessel.

As always, compressed fluids and liquids need adequate safety precautions. Protective barriers and safety glasses are a must. Experiment at your own risk.
 
Last edited:
dnewton, my point was that having any volume of stored energy (compressed gas) is less safe than none.

Down here, using compressed gasses in testing pressure equipment is frowned on. Not illegal, but the checks and balances to legally do it are pretty tough.
 
Originally Posted By: Shannow
dnewton, my point was that having any volume of stored energy (compressed gas) is less safe than none.

Down here, using compressed gasses in testing pressure equipment is frowned on. Not illegal, but the checks and balances to legally do it are pretty tough.


These tanks will be placed near a solid rock wall and I will be hiding behind a hill and some trees. I'm kinda hoping one will blow up...just so I can see what happens.
grin2.gif
This is the same area I have been known to blow up small propane tanks with my .44 Magnum.

Now, if I was just doing this in my back yard, I definately wouldn't be using air.
 
Status
Not open for further replies.

Similar threads

D
  • Locked
Best anti-rust setup for rusting gas tank.
Replies
15
Views
4K
dx92beater
C
  • Locked
Gun oil article
2 3
Replies
40
Views
35K
wpod
T
  • Locked
Best Way To Desludge This New-To-Me Dodge Dakota w/4.7L V8?
3 4 5
Replies
80
Views
36K
Astro14
G
  • Locked
Seafoam and Amsoil PI test
Replies
16
Views
28K
Garak
W
  • Locked
Rust on my truck frame
Replies
17
Views
8K
B20z
Back
Top Bottom