Welding Tips and Tricks

I have a Cast 316L part and the machinists screwed up about 6 holes, they are intended to be drilled and tapped .5-13, 1" deep, but they screwed up and need them filled so they can try again. My issue is I haven't found a good way to fill these holes. With such a long stickout my solidwire just spits and sputters, and anything with flux either MIG or Stick just makes nasty pockets of slag that I have trouble getting out.

Is there a way to make a stable weld so far down a hole? Or some other trick I haven't learned yet?

When I have confronted this type of repair, I over-drill and tap the original hole, make a threaded plug, screw that in, weld the top. Then re-drill and tap properly. Has worked for me every time.

cj737 wrote:When I have confronted this type of repair, I over-drill and tap the original hole, make a threaded plug, screw that in, weld the top. Then re-drill and tap properly. Has worked for me every time.

That's more or less what I've been doing up until now but these holes are too close to the edge for that this time.

Can you post a pic?

Timesert they are a solid type of helicoil but much stronger

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Yikes. That will be tough to repair. Best bet would be to add a bit of filler, then let cool and peen it. Small wire (like 0.030) with a small tungsten to get down in there. By the way, I reread your post. Are you able to try to TIG weld it?

Good luck. I am fearless and repairing that one would scare me

Just curious, what is screwed up? Location?

That close to the edge, why not go in from the side? Have them mill the sides away, then weld from the sides.

cj737 wrote:Yikes. That will be tough to repair. Best bet would be to add a bit of filler, then let cool and peen it. Small wire (like 0.030) with a small tungsten to get down in there. By the way, I reread your post. Are you able to try to TIG weld it?

Good luck. I am fearless and repairing that one would scare me

I could try in theory, havent had much success before, its so deep with so much stickout that getting the wire around the cup is tricky, getting gas in the hole is tricky, and the arc wants to wander over to the wall and I end up with a glob on the wall not at the base.

LtBadd wrote:Just curious, what is screwed up? Location?

All they asked was if I could weld them in, looking at the nonconformance sheet some or all are out of location and or stripped threads. Physically looking at them it looks like someone did a real sloppy job with a hand drill which is weird because I am pretty sure this was done on a mill.

VA-Sawyer wrote:That close to the edge, why not go in from the side? Have them mill the sides away, then weld from the sides.

That is a possibility, and an interesting idea. Let me see what they say to Helicoils, but if they are out of location that wouldn't help. So I might try that.

Another option is a variation on my first suggestion. Overbore the hole, but not on-center. That way the outside edge of the existing hole is the maintained, but the overbore is offset to the existing center. Should allow a plug to welded in, then re-drill correctly.

Any way you slice it, that part is FUBAR and a "best chance repair" is a Hail Mary.

I’m gonna need a definition of FUBAR. Seems like something I can use in the future


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Thanks for all your suggestions, I was presenting options and the powers that be decided to scrap it and order a new casting. I thought we could save it but oh well.

Cost versus rewards. Now it's for you pull out of the scrap and practice on.

I like the idea to open it from the side and then weld it up, try one, since it's scrap already you have nothing to lose

FUBAR F***ed up beyond all repair

weldin mike 27 wrote:Cost versus rewards. Now it's for you pull out of the scrap and practice on.

That is EXACTLY what I’d do. And try every option offered to see what you can accomplish the next time this repair surfaces. You’d be surprise at what you can learn.

Chamfer the hole full depth. IE angled bevel all the way down. Fill it in back out. Tig would be best to keep down the heat.

Poland308 wrote:Chamfer the hole full depth. IE angled bevel all the way down. Fill it in back out. Tig would be best to keep down the heat.

To close to the outer wall.

It wouldn’t matter you will be filling it back in enough to have it remachined. They can dress up the overfill on the outside as well.

Too bad it wasn’t regular mild steel. This is where metal core wire shines.

Only way I think you could do it is with stick and a steady arm.

That doesn't rely on shielding gas the same way TIG does. and I've done it before in holes, just kind of stick it in there and drag it around, do that a couple of times till the hole is full of metal.

It ain't perfect, but with a skinny enough electrode, you might even have a semblance of control.

I guess you could flux core wire it as well? I don't do MIG much so I don't know that one

Olivero wrote:Only way I think you could do it is with stick and a steady arm.

That doesn't rely on shielding gas the same way TIG does. and I've done it before in holes, just kind of stick it in there and drag it around, do that a couple of times till the hole is full of metal.

It ain't perfect, but with a skinny enough electrode, you might even have a semblance of control.

I guess you could flux core wire it as well? I don't do MIG much so I don't know that one

I tried stick like that and it was a fine balance between enough amps to make it melt and not so much that I don't blow the thin wall out. It didn't work well, it made pockets of slag where it wouldn't melt into the wall of the hole.

Dual shield didn't work either, the flux/slag just pooled up on the surface and got thicker and thicker and it sputtered and died the thicker it got. Blocked the arc from continuing to weld. Part of it was the stainless dual shield wire being funky, if it was just mild steel it might have worked.

Delasangre wrote:

Olivero wrote:Only way I think you could do it is with stick and a steady arm.

That doesn't rely on shielding gas the same way TIG does. and I've done it before in holes, just kind of stick it in there and drag it around, do that a couple of times till the hole is full of metal.

It ain't perfect, but with a skinny enough electrode, you might even have a semblance of control.

I guess you could flux core wire it as well? I don't do MIG much so I don't know that one

I tried stick like that and it was a fine balance between enough amps to make it melt and not so much that I don't blow the thin wall out. It didn't work well, it made pockets of slag where it wouldn't melt into the wall of the hole.

Dual shield didn't work either, the flux/slag just pooled up on the surface and got thicker and thicker and it sputtered and died the thicker it got. Blocked the arc from continuing to weld. Part of it was the stainless dual shield wire being funky, if it was just mild steel it might have worked.

Damn, well there you go.

Tig would be nearly impossible without a line of sight.

What if you just threaded it as is, screwed in a stud (cut the head off a bolt) then weld over it?

Won't be watertight but it might get you by?