Removing seized and sheared bolts.

[ajlelectronics]

Well I have started to drill them out. It turns out that my centre pop is made of chocolate! No idea where that came from! I have others though. Started drilling to find that a) my bits are blunt and b) The drill battery is flat! Waiting on some new Cobalt bits and the battery to charge.

 

[Hopefuldave]

What's Alum?
Will it dissolve the steel but not the alloy?

Potassium aluminium sulphate, and it dissolves the steel (well, the iron in the steel) but doesn't affect the aluminium, being an aluminium salt already.

Works best as a STRONG solution (dissolve in boiling water until adding more leaves crystals, a saturated solution) and hot, with the occasional stirring - isn't exactly quick, but can be left to work while you do something else (day at work, scoff supper, down the pub, fall asleep on the sofa and wake up freezing at 4 a.m., repeat - in my experience)

Before Pixie Protection went mad you could buy nitric acid and drop some into the thread where it would eat a bit of the steel and less of the ally while you watched...

Dave H. (the other one)

 

[Dcal]

Potassium aluminium sulphate, and it dissolves the steel (well, the iron in the steel) but doesn't affect the aluminium, being an aluminium salt already.

Works best as a STRONG solution (dissolve in boiling water until adding more leaves crystals, a saturated solution) and hot, with the occasional stirring - isn't exactly quick, but can be left to work while you do something else (day at work, scoff supper, down the pub, fall asleep on the sofa and wake up freezing at 4 a.m., repeat - in my experience)

Before Pixie Protection went mad you could buy nitric acid and drop some into the thread where it would eat a bit of the steel and less of the ally while you watched...

Dave H. (the other one)

Every days a school day.

Can you buy Alum without having a doctors note?

 

[Seadog]

It's used in pickling. Try the chemist or your local hardware store.

 

[ajlelectronics]

Now I have snapped off an HSS bit in the blind hole! That's enough carnage for today I think!

 

[angellonewolf]

oh i near done that when driling mine as well

 

[a111r]

Welding might work better now?

 

[Ali]

I’ve got a set of extractors that I can only describe as a splined rod (multiple sizes) with a corresponding nut. Much better than the LH tapered type, have never let me down. I can’t find a pic on the web. Can’t beat the welding method though.

 

[slim_boy_fat]

Now I have snapped off an HSS bit in the blind hole! That's enough carnage for today I think!

 

[Matchless]

LH drills can be very useful,

 

[Seadog]

Now I have snapped off an HSS bit in the blind hole! That's enough carnage for today I think!

Alum it is, then

 

[Hopefuldave]

Now I have snapped off an HSS bit in the blind hole! That's enough carnage for today I think!

Alum will eat HSS too - eventually

Dave H. (the other one)

Beat me to it!

 

[Shox Dr]

Mine’s a pint

 

[graffian]

I’ve not tried it myself. From watching ut videos, agitating the solution and heat speeds up the reaction

I was going to ask if you had tried alum?
I added as much alum as I could get in solution then a load more for luck, the water was almost boiling when I did this.
I dunked a chunk of warmed ali with a broken tap in the solution and kept it hot, I had to keep adding water as it evaporated
and more alum for luck.
The steel fizzed like crazy but after an hour and no visible change, except the steeel and ali were duller, I took it off the heat and left it,
after a week or so the water had all evaporated and the steel is still stuck in there.

I used to use sulphuric acid, battery acid was 50p a litre from lucas and ideal for this, and a battery charger. Basically your anodising.
Last thing I removed was a broken roll tap, took about 4 afternoons at a couple of hours an afternoon to remove it compelty.

Weld is fastest.

 

[Shox Dr]

I was going to ask if you had tried alum?
I added as much alum as I could get in solution then a load more for luck, the water was almost boiling when I did this.
I dunked a chunk of warmed ali with a broken tap in the solution and kept it hot, I had to keep adding water as it evaporated
and more alum for luck.
The steel fizzed like crazy but after an hour and no visible change, except the steeel and ali were duller, I took it off the heat and left it,
after a week or so the water had all evaporated and the steel is still stuck in there.

I used to use sulphuric acid, battery acid was 50p a litre from lucas and ideal for this, and a battery charger. Basically your anodising.
Last thing I removed was a broken roll tap, took about 4 afternoons at a couple of hours an afternoon to remove it compelty.

Weld is fastest.

You learn something everyday.

 

[Nick67GT]

Well I have started to drill them out. It turns out that my centre pop is made of chocolate! No idea where that came from! I have others though. Started drilling to find that a) my bits are blunt and b) The drill battery is flat! Waiting on some new Cobalt bits and the battery to charge.

You’re welcome to try this out if you want:




Edit: just seen your post about the snapped drill.......

 

[wristpin]

As per Dcal above, I would make a 3mm Thick washer, Nice fit on the stud and large enough to get a good fillet weld to the nut, Let it cool and unscrew (fingers crossed) Forward and backwards, A little at a time.

Particularly if the sheared stud is flush or sub surface. A lot easier than welding down through a nut - either half or full. I always lay a couple of bits of mig wire under the washer so that the shrinkage on cooling doesn't pull the washer tight against the surface.

 

[ajlelectronics]

Particularly if the sheared stud is flush or sub surface. A lot easier than welding down through a nut - either half or full. I always lay a couple of bits of mig wire under the washer so that the shrinkage on cooling doesn't pull the washer tight against the surface.

The stud is now subsurface with a shallow depression where I have been trying to drill out the remains.

If I understand correctly, the next step is to try to weld to the remains and make a column. Then drop a thick washer over the top and weld together. Then drop a nut over the top and weld again?

 

[Dcal]

Here's an earlier post showing the weld method getting a steel bolt out of a bit of alloy. A lot smaller same process.

https://www.mig-welding.co.uk/forum...en-bolt-in-manifold.92372/page-2#post-1371004

 

[Gareth J]

You shouldn't have given up on the welding until you'd sheared off the stub at surface level multiple times. To the point where you couldn't get a stick out of migwire to contact the to of the steel accurately, even if it's recessed a few mm.

As mentioned above, working it out back and forth, when cold, with lubricant is paramount. Be not afraid of welding the alloy, it's so conductive (heat wise) you'll struggle to melt things, put a washer or a nut over if needs be but just blobbing mig weld in the sheared face is pretty easy. Keep building up the blob of weld on the steel and see where you end up. Can't be worse than your current predicament.

Welding in this way has failed me, but only once. On a crappy British seagull motor, on a 1/4" thread that was in deep, maybe up to 1". I don't know for sure as I scrapped it. It was very corroded.