Silver brazing for stainless tank repair?

[WaldPinkler]

There's some pitting on my water tank which is now sitting up on the bow deck.

It's not that bad, just where it's been sitting unsupported against the hull.

I've been searching around the internet to repair. It seems this knowledge is hard to find. Often it's just knowing what to type.

There's silver brazing rods. It it possible to dremel out smaller holes and use silver brazing rods to solder fill them? I watched some videos, it didn't look that difficult. I've done plenty of electronics soldering.

Otherwise grind and jb weld fill?

[OzeLouie]

Hi WP, We use soft plumbers 50/50 solder with EziWeld 801 flux to join stainless. Suggest solder a 'patch' over the area worn through. Using solder means you shouldn't burn the ss. Use a soft, cool flame and perhaps practice with a scrap first.
Cheers Louie

[C420sailor]

The gold standard here is going to be a TIG weld job, with proper gas backing.

[WaldPinkler]

TIG welding looks like a bigger step up.

Then there's

silver soldering on youtube videos

that looks like electronics soldering but not getting things too hot.

Hardware store has 45% silver solder for $35.

Of course I have no experience doing it. If it was like electronics soldering life would be easy. Not a structural problem.

[Turtle Blues]

Original water tank from '67 was folded seam ss. All seams then soldered with I'm guessing 50/50 as Louie describes.

[thinwater]

I'm not sure filling pits with a dissimilar metal is going to help anything. You don't have a leak and you don't have a structural problem. You just want stop corrosion. A coating is what you want.


TIG welding is also a good option if the pits are severe. Often it is hard to gauge the depth. Try one of these:

[WaldPinkler]

Unfortunately there's a slight leak so I at least have to seal that.

I'll check some of the pitting with the dremel tomorrow to see how much is hidden below the surface.

I was hoping to open up and holes and fill them. No one wants to reweld a whole sheet or replace a tank!

[Hermia II]

Hi there,
Please let me stick my neck out......some light Dremel, clean with Thinner and....Epoxy???
It's worth a try!

[Mithril Bham]

Welding is way to go. JB Weld possibly? Silver solder doesn't seem right to me.

[C420sailor]

No, just weld a sheet SS patch over the pitting/holes. I wouldn’t rebuild the tank unless it’s a total disaster.

[oleman]

In the USA Prince & Izant Co. (princeizant.com) mfg various silver soldering base metals with the correct flux recommendation for all types. I have not used any for anything other than brazing fittings. It works well following the company recommendations. NOT cheap, we paid $65. US for 1 M of .062, ON 04/09/18 but goes a long way, I keep the the AG45CU15ZN16CD24 SOLDER UNDER LOCK AND KEY.

[fourlyons]

With a mapp gas welder the silver solder works just fine, I have done it. If you can electrical solder well, then you already know the principals, you just need more heat. As Thinwater said, you probably need to coat it to protect it in the future, at least where it is touching.

[WaldPinkler]

I'm just worried that I couldn't find posts of other people doing this. It doesn't look all that difficult. They just used a propane torch in videos with the right flux. It's strong enough and not really going to peel like epoxy may.

There is the dissimilar metal part, I've had trouble with brass bushings on my old trailer sailer rudder stock. Then again, all circuit boards have dissimilar metals but no real moisture. I don't know the chemistry side of things.

I mean it's the tank under the seat too. I don't care how it looks. I couldn't see that side against the hull anyway.

I will be getting some sort of feet/mounts to keep the tank off the wall and water being trapped like it was.

[Ramona]

Silver solder works fine on Stainless steel. Make sure you use the correct flux. Gas blow torch is ample to get the steel hot. I would still put a small patch over the area. Clean both surfaces and smear flux on the patch. Heat the area till it's glowing red and put the silver solder rod at the edge of the job. As the solder melts blow it around the whole patch. The solder will go everywhere you placed the flux.

[Ramona]

I should add that there are several grades of silver solder from about 5% and up. Obviously it gets more expensive as the amount of silver increases. Buy from a plumbers supply shop and get expert advice.