[Delasangre]

I am being asked to fill in a number of holes in a stainless casting. the holes are drilled 5/8" deep and threaded 1/2 coarse. they want them welded in so they can re do the holes. I have never had luck filling holes like this. especially in stainless because i only have that filler metal in Tig or Stick rod. anyone have some tips for me?

[cj737]

Rotten job. I’ve always plugged them with a stainless (or aluminum when that’s the metal) then welded those in. Then re-drill the hole.

Hard to say exactly without some pictures, but any way you slice it, that’s a bear of a repair.

[Spartan]

Here's a trick that has worked for me in the past...but it may not exactly be up to code, so use your own judgement on it.

Clean the holes out as best you can with a small enough tube brush and degreaser followed by acetone or contact cleaner. Cut up some of the appropriate filler rod into little 1/8"-3/16" bits and put a single layer or so of them down into the hole. Give yourself enough tungsten stick out to reach the bottom and swirl the arc around to melt/fuse the filler rod bits into the base metal. Run it nice and hot. Repeat doing layers of that until you get it up to a more manageable depth and can use filler rod normally.

God speed. A crap job indeed.

[BugHunter]

I would drill out the old threads so you've got a nice straight-walled hole, then fill it. Obviously it'll make it much easier to clean.

(edit)
Unless they're going to thread-mill the new threads in, I feel bad for whoever is paying for the taps to re-tap the holes.

[kiwi2wheels]

Tell them the heat will distort the part too much and suggest these ( or something similar ) as a fix.

https://jet-tek.com/tridair-keenserts-i ... g-element/

[tweake]

would tapering the holes help?
even of you got a big drill bit and drilled out a bit more to give some more room.

[Delasangre]

Here's a trick that has worked for me in the past...but it may not exactly be up to code, so use your own judgement on it.

Clean the holes out as best you can with a small enough tube brush and degreaser followed by acetone or contact cleaner. Cut up some of the appropriate filler rod into little 1/8"-3/16" bits and put a single layer or so of them down into the hole. Give yourself enough tungsten stick out to reach the bottom and swirl the arc around to melt/fuse the filler rod bits into the base metal. Run it nice and hot. Repeat doing layers of that until you get it up to a more manageable depth and can use filler rod normally.

God speed. A crap job indeed.

I thought about this, I might give it one try Monday and see if it works, but I got the arc to arc on the bottom of the hole and i wasn't getting any gas that far down so idk if it'll work.

I would drill out the old threads so you've got a nice straight-walled hole, then fill it. Obviously it'll make it much easier to clean.

(edit)
Unless they're going to thread-mill the new threads in, I feel bad for whoever is paying for the taps to re-tap the holes.

The existing holes are thread milled and I assume they will be doing that again after.

Tell them the heat will distort the part too much and suggest these ( or something similar ) as a fix.

https://jet-tek.com/tridair-keenserts-i ... g-element/

We stock those, I tried and they said no.

would tapering the holes help?
even of you got a big drill bit and drilled out a bit more to give some more room.

Yes, I sent it back to the mill and asked for that and my lead was on board and then the production manager walked by and said "These shouldn't need any more machining, just weld them" and send it back before the machinist could even look at it.

[Poland308]

Bevel it out so you can weld it back in. Takes more time but guaranteed.

[Spartan]

Here's a trick that has worked for me in the past...but it may not exactly be up to code, so use your own judgement on it.

Clean the holes out as best you can with a small enough tube brush and degreaser followed by acetone or contact cleaner. Cut up some of the appropriate filler rod into little 1/8"-3/16" bits and put a single layer or so of them down into the hole. Give yourself enough tungsten stick out to reach the bottom and swirl the arc around to melt/fuse the filler rod bits into the base metal. Run it nice and hot. Repeat doing layers of that until you get it up to a more manageable depth and can use filler rod normally.

God speed. A crap job indeed.

I thought about this, I might give it one try Monday and see if it works, but I got the arc to arc on the bottom of the hole and i wasn't getting any gas that far down so idk if it'll work.

FWIW, I ran a few tests on this exact scenario about a year or so ago before doing the actual repair. After I filled the holes in a piece of scrap round stock (they weren't threaded, but shouldn't make too much of a difference), I faced off the part in the lathe taking several very light passes each time to inspect the weld in layers looking for any voids or inclusions. There were none.

Try a smaller cup size and bumping up the flow a bit if you're having issues getting the shielding gas to the bottom of the hole. May seem counter-intuitive, but it can help. And, again, run it hot, and be mindful to not allow for any voids as you swirl the bead around.

[Delasangre]

So the little bits of filler in the hole didn't work very well. For one there were 12 holes and cutting the filler was very hard and tedious. I ended up drilling the 1/2-13 threads out with a 1/2 drill and using a 60 degree countersink bit to cut as big a chamfer as I could and then with a smaller nozzle and more gas I managed just barely to fill up the holes. What a pain.

[Poland308]

It sucks, but it works!