Who can tell me what's wrong in this pic?

[Rameses]

You can try that after you break off the extractor.

You *really* don't want to break off an extractor in that hole.

Yeah, I've been there before.

I think the last time I had that happen was about 15 years ago though.

Hopefully I won't get a reminder of how badly that sucks.

[Rameses]

So you're gonna mig  and retap the aluminum cases? 

I think not Keemosabe.

Why not?

[ducpainter]

Why not?

You'll never burn out the impurities with a mig.

Welding cast aluminum is tricky for an expert with a tig because of the oil that soaks it way into the pores of the casting.

I don't know a pro that would even try it with mig...it's just the wrong process.

But don't listen to me...what would I know...I'm just a painter.

[Rameses]

You'll never burn out the impurities with a mig.

Welding cast aluminum is tricky for an expert with a tig because of the oil that soaks it way into the pores of the casting.

I don't know a pro that would even try it with mig...it's just the wrong process.

But don't listen to me...what would I know...I'm just a painter.

So a TIG arc has a higher temperature than a MIG arc?

And I have access to a TIG, it's just not that convenient.

[ducpainter]

So a TIG arc has a higher temperature than a MIG arc?

And I have access to a TIG, it's just not that convenient.

Mig is not a penetration process. It's also DC. You need AC to weld aluminum castings.

To fill that hole you have to keep the puddle molten as it fills.

You'll need a lot of amps to do it. Don't ask me the number, but if you get stuck I have a book that has the info in it.

[Rameses]

Mig is not a penetration process. It's also DC. You need AC to weld aluminum castings.

To fill that hole you have to keep the puddle molten as it fills.

You'll need a lot of amps to do it. Don't ask me the number, but if you get stuck I have a book that has the info in it.

I've never welded cast aluminum before. All of the aluminum I've welded over the years has been plate and angle, so that's new to me.

Hopefully it won't come down to that, but I'll remember that if it does and get in touch with you.

Thanks Nate.

[ducpainter]

I've never welded cast aluminum before. All of the aluminum I've welded over the years has been plate and angle, so that's new to me.

Hopefully it won't come down to that, but I'll remember that if it does and get in touch with you.

Thanks Nate.

Just like plate and angle, that casting is a huge heat sink...and probably thicker than what you've welded in the past.

I watched a guy welding a large 1/2" plate weldment at 400 amps. The filler rod disappeared like spaghetti into Kent.

[Rameses]

Just like plate and angle, that casting is a huge heat sink...and probably thicker than what you've welded in the past.

I watched a guy welding a large 1/2" plate weldment at 400 amps. The filler rod disappeared like spaghetti into Kent.

[Bigbore4]

<Snipped>

No TIG here, just MIG.

Regardless, how would you weld a stud to the remaining piece if it's broken inside the case?

If you are still fighting it, screw the stud.  Get a good supply of 3/8 or 10 mm nuts.  Center the nut over the broken stud, protect the piston, rings EVERYTHING and center the MIG gun over the nut.  Weld the nut to the broken stud.  I have a good MIG, not sure if a flux core rig would work.

Start working it while it's still hot, easy back and forth.  I twisted the weld off 6 or 7 times, but the weld bead kept building higher and higher, finally got enough material standing proud to get a really decent weld on it.  Once we had a good hold the stud freed up and backed out.  No re-threading no aluminum welding no nothing. Just some new and improved aftermarket studs.

It was the kids bike, I was the technical lead.  I have no idea what kind of studs he used, he did the disassembly and reassembly, I just saved the case from certain disaster.

[Monsterlover]

Here we go.  That didn't take as long to upload as I thought it would.



Effing Broken Stud



With this setup it only took about 7 hours of drilling to get deep enough to use an extractor.   

I can't decide if I should be ashamed to have witnessed this or impressed at your ingenuity

I'll go with the latter

nice

[Jobu]

when is it set to catch fire?

About five minutes after I get the confirmation that my insurance has been upgraded to full coverage.

Just like plate and angle, that casting is a huge heat sink...and probably thicker than what you've welded in the past.

I watched a guy welding a large 1/2" plate weldment at 400 amps. The filler rod disappeared like spaghetti into Kent.

More like beer, especially this summer.  And don't you have something to go paint? 



Well, tried heat, hitting with a punch and hammer, and using a couple different extractors with and without the impact driver.  Stud isn't budging.  Why the make the beast with two backs did Ducati use stainless steel studs? 

Anyway, I'm just gonna drill through it.  Better than halfway there as it is.  Hopefully then I can get the rest out, without f'ing up the threads too bad.

Thanks for the suggestions.

[Speeddog]

If you can, try to get a left-hand drill bit.
Sometimes those will work at spinning the stud out as they drill.

[Jobu]

If you can, try to get a left-hand drill bit.
Sometimes those will work at spinning the stud out as they drill.

Thanks, I know that, but couldn't find any.  One more tool place I need to go to look for some.

That also brings up another question:

Does anyone know how deep the stud hole is drilled in the case?  (How much space do I have before I start drilling the soft case once I'm through the stud?)  I have a reference by looking at the new studs compared to the broken one, but I'd like an estimate of the hole depth. 

[Speeddog]

http://www.mcmaster.com/#left-hand-drill-bits/=965prm

Dunno how deep the holes are.

[ducpainter]

Standard practice is to have a shoulder on the stud so it doesn't reach to the bottom of the hole yet can still be tightened.

From the pics it looks like that is the case. As hard as the stud is drilling you should know when you reach the end.

Another possibility is the hole is open to the crankcase and the threads are sealed, in which case it's more an issue of getting chips in the cases.