Just made a sump. How do I seal the weld leaks?

[AC sports]

As it says guys.
I cut up and extended an old sheet metal sump, added trapdoors and a baffle... Happy with the result but im not a welder and I used a mig on the 0.050" sheetmetal.
I was expecting a few leaks.....
So:
1, Any tricks to finding them? I used kerosene but may add some colour to it to make the leaks more visible.
2, how do I seal them up? Re mig or can I use a soft solder over my suspect welds?
3, Will a soft solder hold in the long run? Any issues using it as a sealer over my suspect areas so to speak?

[Dutchman]

Spray a soapy solution on the outside of the pan and blow compressed air on the inside.
Warm the pan up with a torch and recheck,may expose a bad weld when it's hot also.

[Walter R. Malik]

As it says guys.
I cut up and extended an old sheet metal sump, added trapdoors and a baffle... Happy with the result but im not a welder and I used a mig on the 0.050" sheetmetal.
I was expecting a few leaks.....
So:
1, Any tricks to finding them? I used kerosene but may add some colour to it to make the leaks more visible.
2, how do I seal them up? Re mig or can I use a soft solder over my suspect welds?
3, Will a soft solder hold in the long run? Any issues using it as a sealer over my suspect areas so to speak?

IF they are merely pin holes or seepage ... Brush-on some fiberglass resin over the entire weldment on both sides is the easiest solution.
Paint it with "hammer finish" paint and you'll never see it.

[prairiehotrodder]

I have welded on lots of sumps with a mig. There is always a leak or two no matter how perfect the weld looks. I cut a chunk of an old tire tube with the valve stem on it and hose clamp it over the filler neck of the gas tank. Then pressurize the tank with a few PSI of compressed air and use soapy water to find the leaks. Then mark them, let out the air, fix them with the welder, Re-check.

Brian

[chevyfreak]

1, Any tricks to finding them? I used kerosene but may add some colour to it to make the leaks more visible.
2, how do I seal them up? Re mig or can I use a soft solder over my suspect welds?
3, Will a soft solder hold in the long run? Any issues using it as a sealer over my suspect areas so to speak?

Been thru the sump building and modifying proses couple of times. Tracing leaks can be tiresome. Take your time double check everything. Worst frustrating moment is finding a leak when its in the car, and as mentioned heat it, or leave it out in the sun with your checking fluid in seperate container, when nice and hot then recheck it. Can use hydraulic oil as well as most is sae10, or brakefluid.
Best way to seal your weld is solder all over your welds on the outside.
The reweld where it leaks doesnt always work or makes it worse. Sadly i had one of those before.
Silicone Sealer or an epoxy doesnt hold, as a temporary fix its ok, but not in long run.

Chevyfreak.

[Caprimaniac]

I have done a couple. Used mostly water.
Grund down leaky points and rewelded.

However- last I did had so manu leaks and very hard to locate soI gave up and thrashed the whole thing.

Ended up buying new sump- with issues too...

[AC sports]

So a soft solder melted into the suspect areas will hold long term?

[BOOT]

Long ago when young and broke a friend of mine had a rusty leaky oil pan on a farm truck he bought and it was before computers so maybe that's why the salvage yard gave him the wrong dipstick/seal oil pan. Anyways he decided to use silicone cause we had to have it back together so he could work Monday. We wire wheeled n coated the entire sump with a tube of clear silicone I had, thing must of had 50 or more pin holes but it didn't leak! Later when he blew that engine up, I bought the truck and pulled that engine to replace it. That pan still didn't leak but you could see thru the clear silicone the oil seeping in a few spots but not leaking LOL

[Protech Racing]

You can also use some flux and braze the leaky spots.

[engineguyBill]

^^^^^^^^^^^^^^^^ THIS ^^^^^^^^^^^^^^^^^^

Or, silver solder.

[Schurkey]

We used to have to deal with 3" tubing, bent sections welded together, and beaded on each end to retain a silicone-rubber hose connection for use with City Bus cooling systems. Lots of it was brass tubing, some was stainless, some was coated mild steel.

The company that supplied the tubes couldn't weld worth a shit. It's like they were made by some guy in his home shop, using Harbor Freight equipment.

We re-welded the tubes until they didn't leak. Never considered soldering them. 'Course, these tubes would be pressurized by the "radiator cap", whereas an oil pan has little or no pressure inside; and maybe vacuum.

[BigBlocksOnTop2]

That s the thing with wire feed welding a fluid vessel. The starts and stops can cause a slag pocket. With time and vibration the slag pocket cracks out and there's a leak. Been there and done that. Nice looking welds too, not to mention. Just the beast with wire feed welding. TIG is the way to go....

[AC sports]

Update on this. I ground the welds down and re did them. Much better job....but 2 small weeps. May do those areas again then melt some soft solder over the area.

[dondon]

i had a pin hole in an oil pan, I painted it with por 15 that stopped it. pan was off when I painted it.

[stealth]

Clean well and coat with jb weld. Smooths over the poor appearance of weld area and seals very well...