Large Scale Central

Not LS, sheetmetal question

Problem Solving
#1

I’m trying to fix a 95 year-old galvanized makeup water tank. It is (was?) riveted, painted, heavy galvanized steel. Unfortunately, the lower sides now resemble Lorraine Swiss. The pinholes are bad enough, but there’s also a 9" long horizontal crack about 2" above the bottom on one side, right where the crap in the bottom had accumulated.

Yes, it would probably be easiest to simply replace it but since it is the original tank, I’d prefer to fix it. I’m looking for either 1. a way to make it look original again, or 2. surface patch it to make it look like a vintage repair. There are just too many holes to simply braze it.

Oh, and yes it does need to hold water. It’s been suggested that once it’s “fixed” I should dump a couple quarts of polyurethane varnish in it and slosh it around. (slosh? it’s 2 feet square, almost 4 feet tall, and weighs over 100 pounds! Slowly roll it around the yard, maybe). Anybody have a better idea?

I’ve got the tank dismounted, I will get photos soon.

#2

Check this link for removing rust. http://www.oddfiddlythings.com/2011/rocketsled/deironoxide/

#3

Here is another link for removing rust http://1bad6t.com/rust_removal.html
In the conversation with users
I haven’t set one up yet, but I have a good friend who’s a chemist, and he suggested that I use Trisodium Phosphate over washing soda or lye.
He said it would anodize the parts as it removed rust and such.

I still need to get around to setting this thing up. But I’ve been using this citrus-based solution that’s working pretty well, so I haven’t been hugely motivated.

a 4.5 lb box of TSP online for $20 with shipping.
You can’t buy it in MI.

You need to be careful of the fumes in an enclosed area with whatever you use. The larger the tank, the more reaction to release gases.

Started using Arm & Hammer, but some-one from this site suggested - Drain Ocleaner with Lye. Much better results from the few X’s that I used it. My #122 nose is still cooking away, 4 days.

#4

How big is the opening in the top?? You could try lining it with some thin stainless and use RTV in all the corners and edges

#5

When you get rid of the rust then you could use a fuel tank sealer or use fiberglass resin, just the resin not the fiberglass.
I think the first option is best though. Is what I used on a gas tank that I couldn’t find a replacement.

#6

Hi Mik,

The chemicals suggested may remove the rust good enough to solder up the tank but you must remember removing the rust by any means only increases the size of the rust out holes.

I don’t think “brazing” is a very good idea. To get the metal hot enough to take the brass you are going to do two things. Burn up the thin edges of the rusted areas and produce lots of toxic smoke from the burning zinc.

The fact that molten metal, in this case brass, will not fill a hole by fast freezing to the edges like you can do filling up your blow holes with a stick arc welder process. Soft solder which I would highly recommend for this process will however give you the same grief with the falling through the holes.

Without inspecting the tank, all that follows is simply guess work.

If it is only a few holes in isolated locations you can try riveting a back plate behind the holes to prevent the fall through. BUT, remember that to solder correctly the base metal has to be absolutely clean and free of rust inside and out or the solder will not properly adhere. Of course to do the above you must open the tank up enough to get inside to work, kind of ruins the looks unless you can install an entire new side or bottom where it will not show on the finished product.

The best solution, of course, is to build a new tank. Remove any original fittings and solder them into the new tank. Hand buck rivets are still available and easy to use. For a galvanized metal tank I recommend Tinners fluid as flux and 60-40 soft solder applied with clean hot irons.

An easy project with the correct tools :)=)

I built and rebuilt hundreds of old tanks for everything from tractors to wood stoves
during my 35 years in the sheet metal shop.
If I can offer any help, just ask.
Rick

#7

Maybe the best solution for holding water is to insert a plastic bucket inside your repaired metal tank. I’d suggest careful cleaning of the rust, then filling the holes with bondo (metal filler for automobiles), as you’re not holding back a lot of pressure. You might paint the inside with the stuff people spray on their pickup truck beds for liners.

Second the motion to put up some pix.

#8

There is a 2" diameter hole in the top. and one in the bottom. The one on top has a 8" extension riveted in place

When I said Lorraine, I meant it. We’re talking 150 or maybe more from pin holes to about 1/8". You could make a lawn sprinkler out of it.
We thought about the bed liner stuff, but they wanted us to drill out the rivets to remove the top

#9

If you don’t want to rebuild it but keep all the oldness of of as is, at this point I’d be thinking of using the old tank only as a kind of disguise or costume for something else you could put in there to hold water. A new big plastic bucket, maybe, from a farm equipment place…? Yeah, I’m going with Dick’s idea here. Let the existing holes serve as drainage!

#10

Photos:

(http://i397.photobucket.com/albums/pp52/steamnut1917/P1010004_01.jpg)

(http://i397.photobucket.com/albums/pp52/steamnut1917/P1010005_01.jpg)

(http://i397.photobucket.com/albums/pp52/steamnut1917/P1010006.jpg)

I’m thinking since the crack is already so long, and the metal above it is so thin, perhaps I should just cut a hole big enough to reach into - then scoop out all the crap and multi-coat the other 3 sides with polyurethane before patching it over with a 8x16 piece of 16ga sheet, a wide bead of rtv and sheetmetal screws