Will heating a steel frame up, damage its strength?

[MrWill]

might try that with a long bar on the pipe wrench.....

Yeah, don't apply constant pressure though. Bounce it, if you get what I mean. Have it on a flat bench with the seat post hanging over the edge. Warm it up with a hairdryer first.

 

[simon the viking]

Sorry I meant impact wrench not torque wrench! On another planet.

I did wonder.... I sell tools and thought I must look into to what they are......

 

[Drago]

I had thought of caustic sode in through the bottom bracket then leaving it upside down....

its an all too common problem in olde MTBs. The Retrobikes boys use the technique a lot.

 

[Globalti]

A hair dryer won't make any difference. By the time you've raised the temperature of the seat tube, the seatpost will also have heated up and in any case the expansion differential won't be enough. The problem is the oxidation, oxides take up more space than metals so have expanded and filled the gap between tube and post. If the frame won't turn around the post held in a vice, the only option is complete destruction of the seatpost, either by cutting or by melting with caustic.

 

[petergc]

You could try boiling hot water then freezing it straight away?

View: http://youtu.be/54WhdrLKKvY

I know they have a carbon model but I'm sure it's worth a go

 

[Gravity Aided]

Hot vinegar?

 

[andrew_s]

A hair dryer won't make any difference. By the time you've raised the temperature of the seat tube, the seatpost will also have heated up and in any case the expansion differential won't be enough. The problem is the oxidation, oxides take up more space than metals so have expanded and filled the gap between tube and post.

The point of heating isn't to expand the seat tube more than the post, but to drive off the water that makes up a significant part of the bulk of the white aluminium oxide that's jamming things up. Heat to > 100 deg, keep it there for a good while, then run plusgas in as it cools and try force again.

Caustic soda will definitely work, but is dangerous stuff, so wear all the protective gear (incl goggles)

 

[Gravity Aided]

Goggles, gloves, rubber apron. Caustic soda reactions can be vigorous.

 

[Globalti]

Watch it on Youtube, it's almost frightening.

 

[Bodhbh]

Caustic soda will definitely work, but is dangerous stuff, so wear all the protective gear (incl goggles)

^^

And just adding the granules to water is very exothermic and liable to burst glass containers if you mix too much at once. It's pretty nasty stuff to be slopping about in quantity tbh, the frame would have to be worth a few $$$ to be worth the hassle of using it and clearing up the mess.

 

[simon the viking]

As O.P..... I'm just going to leave it.... its getting built up as a hybrid and the stuck seat post is bugging me but not the end of the world....but thanks for everyones comments....

 

[ArDee]

^^

And just adding the granules to water is very exothermic and liable to burst glass containers if you mix too much at once. It's pretty nasty stuff to be slopping about in quantity tbh, the frame would have to be worth a few $$$ to be worth the hassle of using it and clearing up the mess.

Much better to add the Caustic Soda granules to water though, than add water to Caustic Soda granules