How to Remove a Seized Seat Post using Caustic Soda

How to Remove a Seized Seat Post using Caustic Soda.
In this video I show you how I used caustic soda to melt an impossible to remove aluminium bicycle seat post in a steel frame. I demonstrate using the caustic soda and the time it takes to remove the seat post from the frame.
Warning, caustic soda can be dangerous so please use appropriate precautions if you plan on doing this yourself.
Timecodes
0:00 - Intro
0:05 - Introduction and safety using caustic soda.
2:09 - Using caustic soda to remove a aluminium seat post.
3:56 - Results using caustic soda.
5:10 - Repainting steel bicycle frame.
I hope that this video helps you in your own bicycle projects. If you are new to the channel then please have a look around, we have many more vintage road bike restorations plus bicycle maintenance videos to help a long the way.
Visit our website for hints, tips and free downloadable vintage bicycle catalogues to give you reference and guidance with your own bicycle restoration.
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Do something amazing, recycle and ride a bicycle!
#stuckseatpost #seizedseatpost #cycling

[@benkeeling1935]

Glad you taken the comments onboard and saved a great frame

[@MrDazP1adv3ntures]

That bike frame looked absolutely spot on Andy ! Very, very impressive, indeed...👌 I'm just so pleased that the efforts you put into removing the stubborn seat post paid off and I am looking forward to the next instalment of this bike's restoration.

[@BikeItUK]

Glad you enjoyed it, yes it’s definitely getting brought back to life. Build coming up soon. 👍 Thanks buddy

[@leehaverstock8034]

Redemption Andy! As a Bob Jackson owner I was sad to see the frame in that state. Thanks for giving it another go. That paint scheme is classy!

[@BikeItUK]

Yes it should make a classic build. Watch this space 👍

[@C345OFR]

Stunning work considering no decals. Glad you included that part, was a nice bonus to the removal of the seat post.

[@BikeItUK]

Thanks buddy, yes it should make a nice build. Watch this space 👍

[@user-px1kj9fo1c]

Thanks for the knowledge. I've been working with my aluminum seat post on my 1981 Schwinn Sidewinder. I'm going to try this. Have a great weekend Mate

[@BikeItUK]

Good luck! Glad it helped

[@adelheid_mueller]

Amazing paint Job 👍, very nice frameset❤, much fun with it!

[@BikeItUK]

Thank you! Glad you like it

[@dinodaniel2237]

Great video! Beautiful paint on the frame. Definitely looking forward to the build.

[@BikeItUK]

Thanks glad you liked it. Thanks for your feedback it’s appreciated

[@thomasqqcouperji4491]

Bob Jackson classic well done and interesting way to save a frame we’ve all had the stuck quills and seat post

[@BikeItUK]

Thanks for your support and watching. Happy Cycling

[@StanEby1]

Where there is a will, there is a way. Brilliant and beautiful. Congrats.

[@BikeItUK]

Much appreciated thanks for tuning in glad you liked it

[@label2wear220]

Big thanks for such a helpful video, Andy! Your explanation of how to remove a seized seat post using caustic soda was incredibly clear and easy to follow, even for someone like me who isn't the most mechanically inclined. I especially appreciated you detailing the time and effort that it took. Your videos are very helpful. You saved me a lot of time and frustration, and I'm sure your video will help many others too. Keep up the great work! Regards Graham

[@BikeItUK]

Glad it helped! Thanks for your support and watching. Your support is appreciated 👍

[@andymoss]

Brilliant mate! I had to leave a fantastic Peugeot 653 frame in England when I emigrated and left the disassembly too late. Yes, the aluminium seat post was welded into the frame and I’d already sold all my tools. I couldn’t get the frame with post attached into the shipping crate and the movers were waiting.

[@BikeItUK]

Oh dear, shame. Thanks for sharing and watching it’s much appreciated

[@01FozzyS]

Mark to the rescue! Beautiful work as always.

[@BikeItUK]

Many thanks! Glad you like it

[@rubenruizdeurrafernandez2430]

Thank you very much sir!! I have one project stalled becouse of a stuck seatpost. I will try this method. Best regards

[@BikeItUK]

Hope it helps thanks for watching

[@roygardiner2229]

Well done! The frame has been transformed .

[@BikeItUK]

It certainly has, thanks for watching and your support

[@waikeungmak7588]

Bob Jackson bike frame is heavy , but so strong 😊. Will come long lasting 😘

[@BikeItUK]

Definitely out live us 😂👍 thanks for your support

[@waikeungmak7588]

@BikeItUK so joyfully😊! my elder brother had a Bob Jackson road bike with shimano groupset😎

[@JohnPilling25]

On the safety front I would just add that a full face visor would be better than safety glasses. NaOH will severely burn skin. I've used it to remove anodizing, but I use water at 50C before adding the NaOH slowly - also a 30% solution. I weigh out 300g of Solids to add to 700ml of water then once dissolved top up to 1 litre with cold water. Works much more quickly when hot. Good job and very clearly explained.

[@BikeItUK]

Thanks for watching and sharing your experience and knowledge it’s much appreciated

[@petesharp3640]

A good idea that would make for easy work as long as you could isolate all of the fluid in the seat tube. What I could not overcome was how to stop all leaking into adjacent tubes and out of the frame itself. I used uninflated balloons stretched over either side of the BB shell which worked really well. It ran through the holes for the BB cable guide which I successfully plugged with chopsticks. Great. But then it found its way out the chain stays at the dropouts and out the headset, out the stem. Everything is open inside the frame to some degree. Then I flipped the frame, plugged the top of the seat tube and tried filling through the BB shell. Ultimately the same problem. It ended up getting so messy (and dangerous) that I had to stop. If it was just a matter of plugging the BB shell and fill the seat tube it would be a certain fix for all bikes. But you must have a bike with isolated tubing?

[@paullacey2999]

Fantastic to watch👍

[@BikeItUK]

Thank you! Glad you liked it

[@Saints66]

Great video, crack on science man..

[@BikeItUK]

Thanks buddy thanks for the support

[@cal5566]

I'm exactly here, I have a lot more post out... At the cost of putting a screwdriver through the frame. Hopefully will weld up ok. I'm definitely going to have to try this or gallium

[@cal5566]

I'll add this, if I was going to do this again, aluminium post in steel frame, I would buy a long 26mm twist drill and drill the "meat" out of it. I'm confident it would stay fairly centered in the tube

[@BikeItUK]

Thanks for watching and your advice much appreciated

[@user-vr1gw4uz2u]

Great video Andy! can you give us some insight about the welding? isn´t it a crucial spot, which is constantly under tension due to the seatpost clamping therefore making it very prone to cracking again in the welded spot?

[@andypettitt1344]

Fantastic.Great to see that the caustic soda worked,definitely will use it in the future should I have the same problem.The Bob Jackson is a stunning frame,looking forward to the build

[@BikeItUK]

Glad you like it thanks for watching and your support it’s much appreciated. Happy Cycling buddy

[@tangoengineering]

Looks really good now

[@BikeItUK]

Glad you like it 👍

[@alleborgo5481]

I've had same issue on my bike. Unfortunately it's an Aluminium frame and it was a carbon seatpost that was stucked. NaOH couldn't be used. Obviously. I've filed it away with hours of sandpapering. Worked Well but so hardly.

[@BikeItUK]

Oh wow, never had that combination eek. All the fun hay. Glad you sorted it, thanks for your support and happy cycling buddy

[@germurphy4986]

Could you use this to remove a steel seatpost fromman aluminium frame?

[@johnmoruzzi7236]

If you only want to save the seatpost ! 😅

[@BikeItUK]

If it was the seat post you was after saving, and not the frame.

[@lezbriddon]

wished I knew this 20yrs ago before the hammer split my thumb!

[@BikeItUK]

Thanks for watching hope the video was helpful

[@jeremynorth]

While I love your restorations, would it be reasonable to conclude that the time and money you spent to remove the seat post and repair this frame is way beyond what it's worth? As a proof of concept I see the value but the cost of repairing the damage caused by removing the seat post seems unviable unless it has some heritage.

[@BikeItUK]

Yes completely agree, and yes these points are definitely valid. For me personally it’s a little different having the channel and creating content. Thanks for watching and your support.

[@romanmentor9238]

Was it an alumnium seatpost?

[@BikeItUK]

Yes