[Closed] Stuck BB + caustic soda=

Don't strike a match, I think it gives off hydrogen gas. Not that I ever used to fill pop bottles with caustic soda and shredded aluminium foil. Oh no.

Definitely a nice frame worth saving.

Should work. Seen it before on a thread.

Paint will be damaged but should be fine otherwise. My only thought from doing this with a few seatpost is how effective it will be if you just leave it overnight. I redo a bit at a time and refresh the caustic soda so it's working quicker.

I'd have used cola, usually does the trick & tends not to dissolve paint

So? Result??

If you haven't already got it out, if your tool allows it, its helpful to put a long bolt or threaded bar with nuts into the BB so it holds the tool tightly in the splines.

Tried but failed to show boiling a Thomson post out with CS

You are doing it:

1. Outside
2. with a work stand
3. a table and towel under the bowl

I conclude that you have not done this the proper man way of just getting on with it on the living room carpet and risking it all falling over and going everywhere.

1. Outside
2. with a work stand
3. a table and towel under the bowl

4. employing a seal to poke a stick at it - RSPCA?

48inch stihlson on a bolted tool has never failed me yet 🙂

15 hours later and still no update. Time to call emergency services?

Have you tried sticking the BB tool in a vice, and using the frame for leverage? Or a really long stiff pole ( 😯 ) over the spanner to achieve similar?

And does anyone know if sulphuric acid drain cleaner will work as well as CS? As it will eat aluminium, but not steel. Or is it too dangerous? Best to use CS?

If I remember my chemistry lessons correctly Aluminium reacts slowly with both acid and alkali (faster with heat) whilst iron reacts only with acid. So caustic soda would be the weapon of choice here.
Hiw about plugging uo the holes in the frame and then pouring CS down seatpost, the the paint might stay unaffected.

So, best to use CS then?

Wha the hell am I going to do with this drain cleaner? I'm now too scared to even go near it! 😆

At an aluminium extrusion plant I used to work at they would stick the steel dies with the end of alu billet inside in 85 degree CS, 12 hours and the die came out alu free

Update....
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Soon to be seen slowly ridden at this seasons CX events.
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Steel square taper went in like butter (with copious copper slip) Hurrah!

Rookie mistake was not realising the caustic spray would travel up the frame and out onto the aluminum steerer on forks, all stripped and cleaned with only the paint stripped on the drips. Aluminium stem and brakes also have a Patina.

If you are going to do this, totally strip the frame. No aluminium anywhere!
Took me two baths to totally dissolve a whole BB.

I will put on a HTII I/O ring on when classifieds allow.
Wally.

Well done. I can't see a problem with the stuck alloy seatpost I need to remove now. Bring on the caustic soda!

Oh, and how do you neutralise the CS after use?

Good work but wouldn't a penetrating oil like Plus Gas been easier?

I disposed of CS down the external drain with lots of water from a hose, in essence sorted out frame and cleaned drains in one go. I suspect this had gone way beyond Plus Gas and a big bar. In hindsight it was actually quite gentle. I had given the frame such enormous hits with a lump hammer and long bars with pin spanners that I was worried about distorting or cracking the frame.

Great work.

Penetrating oil would take a very long time to work through if really stuck.

Have you a close up of the paint around the BB? Looks white? Did it do much damage?

Without sounding all health and safety, if anyone else is trying to do this, and it works great on seatposts too, then I would suggest watching youtube etc first as it is really horrible stuff.

Quick question, what concentration of caustic soda did you used?
Cheers

3M concentration. (500/40 then /4) or 500g in 4 litres of water.
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All the white bits are as hard as nails and as frame has a drain hole, I drilled through the plastic cable guide to aid drying frame out over winter.

Nicely done. I usually do it in about 15 minutes with a power tool, though 😉

Ho would you have done this with a power tool Ben?

Iirc he uses a hole cutting bit in his drill to remove most of it, prise what's left out and then clean the threads with a pick. Might have remembered wrongly though.

Aye, hole saw with a pilot to cut out the BB, then run through the taps to clear out the threads.