old sheetmetal repair

[Allen]

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 many, many 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/solder 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.

 

[Mosey]

Once you fix it, you might consider sealing the interior with the stuff used for motorcycle tanks, etc.

 

[bearcar1]

Hello Allen. I'm not sure exactly about how to go about making the necessary repairs to that tank but it sounds as if has been neglected for quite some time. Just a couple of things did come to mind though and one is that galvanized treated metal is quite toxic if it is welded or brazed so keep that in mind. The other concern I had was the usage of polyurethane for a sealer. The entire inside of that tank I'm sure is corroded to beat Hell and unless that corrosion is removed or stopped in some way, it will only further deteriorate, sealed or not. Polyurethane will not adhere very well to the corrosion present and will begin to crack, peel, etc. in a very short period of time. If I may suggest, if patching (vs. replacement) is your final decision, that you remove the areas that are corroded through and replace with solid sheet metal. More than likely in doing so you will find that for the most part, the remainder of the tank is becoming heavily corroded inside as well and has just not corroded through the metal. Anyway, if you do find the tank is 'salvageable', then take steps to eliminate as much corrosion as possible from the remainder of the tank and apply a proven coating such as POR15 in an attempt to quell any further corrosion development.

BC1
Jim

 

[Mosey]

Could you cut away one end of the tank, clean up the corroded inside surfaces, insert a new tank closely fitted inside, and then close up the end. Then you would have to cosmetically repair and refinish the outside. Maybe dumb, but worth considering?

 

[90LX_Notch]

I'd make an insert that slipped inside the original to hold the water; then I would fix the major cosmetic problems on the original. The pin holes would no longer be of any concern.



I see that Mosey had the same basic idea.

 

[Noitoen]

For that, you can use some PE sheet and "weld" the seams with a heat gun and PE rod. http://www.ides.com/info/generics/27/Polyethylene-PE

 

[Allen]

Being that it is the original tank for my traction engine, replacement really is my last option.

 

[pkastagehand]

Get some Galv sheet of similar material, bend it (or have it bent) to match the size/shape but just large enough to wrap around the outside of the old tank and go up as high as needed to get to solid old tank. Assuming the bottom is bad too, have this band shaped side thing pre-assembled to a bottom using whatever method was original if you want (rolled, flanged and riveted?) Clean everything then using some water proof adhesive in between layers (in the old days they may have used tar/asphalt stuff) before assembly and then set the old tank down into this new base and then rivet a couple rows around it.

I suppose if it still leaks with the water proofing in between, then you could go the coating route like they do for scale model locomotive tenders, motorcycle gas tanks, etc... I think it is a liquid you pour in, cap it, then roll it around. If you had help you could roll it around the yard for a while. Then drain the excess stuff and let it cure. Of course with the old tank still inside where the water gets to it you may want to seal it anyway, even if it doesn't leak, to keep the water away from the already rusting surface. Encapsulate them so to speak. Otherwise, keep good screens on the intake pipe so you aren't pulling gunk into pumps or boiler.

Except for the modern interior sealer I expect this is how they would have repaired it "back when".

Paul

 

[Allen]

OK, photos:

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

 

[Noitoen]

Since it's painted, I would fabricate a new one out of stainless steel welded all around then weld or glue some dummy rivets for the looks and solve the problem once and for all. It should outlive the rest of the engine.

 

[rustranch]

Depending on how big the access hole is you could line this tank with fiberglass mat and resin. Did his once on a gas tank from a old car worked for me.

 

[Lakc]

Well, it lasted 95 years, I would just reproduce the whole thing. I know a good sheetmetal guy that knows classic car restoration, someone similar could do it for you. If your up to it, draw it unfolded and just follow the pattern.