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Sun Feb 07, 2021 7:30 pm

busdaddy wrote: raygreenwood wrote: ....this used to be much simpler. Phosphoric acid solutions were made for one thing....rust conversion....NOT rust removal. Many of the common products available have changed chemistry RADICALLY in the past five years or so. Some are much weaker...some are much stronger. Some have moved to chelating chemistry and have to be used in a totally different way.....and few seem to bother to download SDS or TDS's to find out,what they have. :wink:

Ray
Indeed, the goal posts keep moving. That's why I switched to the PH down, same results as the "professional" rust converters sold here for 1/8 the cost, you just have to be careful how you use it. (and yes, I followed all the instructions on the pro stuff, still takes off the flash instantly so why bother spending more?).

You may be onto something with using just the Phosphoric, I'll have to give that a try.

Ooooooh......PH down? Not familiar with that one! Lemme look it up!

Always happy to learn of a new chemical that may make it relatively simpler!

Thanks BD!

Ray

Wed Oct 18, 2023 7:52 am

I have a fuel tank that I've pulled from a wrecked 1974 bus. It has minor rust inside and out, and I intend to press it back into service. I will follow the advice of rinsing with muriatic acid and some sort of hardware to gather and treat the loose stuff inside, followed by a treatment with Ospho, and finally a coating of diesel for storage. The outside I will finish like any repaint job.

But I have two questions:

1) How do I protect the still-intact filter sock from damage during the sloshing hardware treatment? I'd hate to damage it.

2) And further, if it does become damaged, how does one replace the sock with a new one?

Wed Oct 18, 2023 8:28 am

A 74 may or may not have a sock, it was deleted mid year....
Look at the outlet, if it has a biggish nut surrounding the nipple it has a sock, if it's just a welded in nipple it has nothing. Remove the nut to remove the nipple and sock, install a penny or some other disc in place of the sock and nipple (put the nut back on) when cleaning and replace the sock when finished.

Wed Oct 18, 2023 11:37 am

jtauxe wrote: I have a fuel tank that I've pulled from a wrecked 1974 bus. It has minor rust inside and out, and I intend to press it back into service. I will follow the advice of rinsing with muriatic acid and some sort of hardware to gather and treat the loose stuff inside, followed by a treatment with Ospho, and finally a coating of diesel for storage. The outside I will finish like any repaint job.

But I have two questions:

1) How do I protect the still-intact filter sock from damage during the sloshing hardware treatment? I'd hate to damage it.

2) And further, if it does become damaged, how does one replace the sock with a new one?

Replace the sock. Better still....get rid of the sock altogether and use an external strainer. I have been stranded more than once by crappy silt in the gas. Cleaning it on the side of the road means you lose the whole tank of gas unless you have something to catch it in.

That, and the more common issues of silt sloshing back and forth causing hard to diagnose intermittent running issues....not worth it. You can Use a cheap external diesel strainer in line. If you think you are getting clogs due to running issues....swap it out and know for sure. $5 at most.

Ray

Wed Oct 18, 2023 6:33 pm

busdaddy wrote: A 74 may or may not have a sock, it was deleted mid year....
Look at the outlet, if it has a biggish nut surrounding the nipple it has a sock, if it's just a welded in nipple it has nothing. Remove the nut to remove the nipple and sock, install a penny or some other disc in place of the sock and nipple (put the nut back on) when cleaning and replace the sock when finished.
I can see the sock by peering into the tank, which is out of the vehicle.

It also has the nut on the outlet, and I have removed the nut. The pipe remains in place, however. Is this supposed to be removed easily? It's hard to know with these old things, amirite? With the large nut gone, how does the rest come out?

Wed Oct 18, 2023 6:39 pm

The pipe has a washer on it the nut was squeezing up against the screen, manhandle the pipe out and then pry the sealing ring under it out, the screen is part of the ring.

If it comes out in chunks it wasn't meant to be, both are available aftermarket.

Wed Oct 18, 2023 6:44 pm

I guess alternatively I could just take my chances damaging or losing the sock to hardware rolling around during the cleaning phase.

Thu Oct 19, 2023 3:20 am

skills@eurocarsplus wrote: fwiw, POR-15 is trash and i have stopped using it. i used to swear by it but it has been nothing but problems for me. i think they changed the formula to comply with VOC issues, and that's when i feel it went down hill X2 I wouldn't use that stuff on ANYTHING anymore! I have seen so many failures of their products. They've always been super strict with prep, but even then it just sucks!

Thu Oct 19, 2023 8:00 am

Jtauxe.....just pull out the tube and sock filter.

D) NOT use piles of hardware and scrap to rattle around in the gas tank. This makes scratches in the metal. Not only are scratches weak spots in the surface which make formed metal MORE prone to cracking and rusting.....they are very tiny "valleys" ....into which the surface tension of most liquids are too high to "wet out", or flow down into. So this can leave very fine, bare, untreated and uncoated spots down in the scratches. It leaves space for oxygen and moisture to create more rust.

If you are using muriatic acid....there is no need to rattle hardware around in the tank. Muriatic acid will DISSOLVE....ALL rust.

If there is anything left after the muriatic acid acid step.....it's a combined stack up layer of varnish and or coating and or rust. You can then treat it with acetone or paint thinner. I use a long rod with a scotch Brite attached to the end along with paint thinner to get any stack up spots like this I can see through the filler neck and sender unit hole. Rinse then use muriatic acid one more time. Rinse and let it flash rust for a day or so. Then use OSPHO.

Ray

Thu Oct 19, 2023 8:33 am

Thanks, Ray
I had not thought about the problem of hardware scratches making new points (and lines) for future problems. Good point!