DoubleDee Posted October 4, 2012 Share Anyone have any advice to loosen carbonfibre seatpost from aluminium frame without doing any damage to frame or seatpost? Thanks Link to comment Share on other sites More sharing options...
kennyg Posted October 4, 2012 Share take the clamp off first... if that doesnt help, try heating the alu gently, with a torch, then try a rubber hammer to caress her out. Link to comment Share on other sites More sharing options...
gummibear Posted October 4, 2012 Share take the clamp off first... if that doesnt help, try heating the alu gently, with a torch, then try a rubber hammer to caress her out. I would try a little Q20 first.Leave it overnight and try tomorrow. Link to comment Share on other sites More sharing options...
Tubehunter Posted October 4, 2012 Share Be glad its not an alu seatpost in a carbon frame! VERY GLAD!! Link to comment Share on other sites More sharing options...
DaLoCo Posted October 4, 2012 Share Use a large flat screwdriver. Insert the tip in the groove on the frame and twist so it opens the frame. Link to comment Share on other sites More sharing options...
gummibear Posted October 4, 2012 Share Be glad its not an alu seatpost in a carbon frame! VERY GLAD!! When you get it out buy some carbon paste before you put it back in. Link to comment Share on other sites More sharing options...
V12man Posted October 4, 2012 Share Use a hairdryer not a torch initially - torch will burn the paint if you do not have good control and practice. I would just use a slide impact hammer to pop it out the top after some anti corrosion oil for a day or two (combined with some heating) TheV 1 Link to comment Share on other sites More sharing options...
Johan Bornman Posted October 4, 2012 Share OK, now that you've tried everything and blistered your paint, cracked the frame, bust a gut and cursed a bit, do it the right way. Aluminium oxide is the culprit. The post was probably greased before inserted. Water gets in there, forms an emulsion with the grease and then proceeds to corrode the alu. Aluminium oxide is a larger molecule than an alu molecule and therefore the alu oxide crystals expanded inwards, trapping the post. No chemical process will reverse this and no penetrant will work. Force may or may not work. Saw the seatpost off, about 25mm above the top of the seat tube. Now insert a hacksaw blade with the one end wrapped around a cloth and proceed to saw the seatpost lengthwise until you touch the frame. It is a long, laborious job but gets shorter with beer. Be patient, do a decent job and don't inhale that horrible carbon dust and don't get carbon splinters in your fingers. Once the seatpost is now sawn through, tap it with a mallet and it will pop right out. The reason why it can now get out so easily is because the corrosion doesn't bond it, but just expands. With a groove in there it can expand inwards and come loose. PS - I notice no-one has suggested the Coca Cola remedy yet? C'mon, get with it! Link to comment Share on other sites More sharing options...
gummibear Posted October 4, 2012 Share PS - I notice no-one has suggested the Coca Cola remedy yet? C'mon, get with it! I don't waist Coke,rather use it in my Brandy. Link to comment Share on other sites More sharing options...
Scooterza Posted October 4, 2012 Share OK, now that you've tried everything and blistered your paint, cracked the frame, bust a gut and cursed a bit, do it the right way. Aluminium oxide is the culprit. The post was probably greased before inserted. Water gets in there, forms an emulsion with the grease and then proceeds to corrode the alu. Aluminium oxide is a larger molecule than an alu molecule and therefore the alu oxide crystals expanded inwards, trapping the post. No chemical process will reverse this and no penetrant will work. Force may or may not work. Saw the seatpost off, about 25mm above the top of the seat tube. Now insert a hacksaw blade with the one end wrapped around a cloth and proceed to saw the seatpost lengthwise until you touch the frame. It is a long, laborious job but gets shorter with beer. Be patient, do a decent job and don't inhale that horrible carbon dust and don't get carbon splinters in your fingers. Quality answer! Nice! The other answers were logical but this is the kind of answer you get from someone who has clearly got experience! Link to comment Share on other sites More sharing options...
MTBer wannabee Posted October 4, 2012 Share Quality answer! Nice! The other answers were logical but this is the kind of answer you get from someone who has clearly got experience! Or maybe did not read the original question. The OP wanted a solution without damaging the frame or seatpost.So I guess the correct answer is that it cant be done. Edited October 4, 2012 by MTBer wannabee Link to comment Share on other sites More sharing options...
urbanroyal Posted October 4, 2012 Share Dude ...I'll just twist it at the saddle till it either comes loose or breaks ... :-) Link to comment Share on other sites More sharing options...
Li Mu Bai Posted October 4, 2012 Share take the clamp off first... if that doesnt help, try heating the alu gently, with a torch, then try a rubber hammer to caress her out.DONT USE A TORCH, jeez. And how can you take the clamp off first? you can loosen it yes. I had the same problem before. seatpost stuck fast. Called JB late on a sunday night for advice. He suggested I use boiling water from a kettle poured over the top of the frame where the seatpost protrudes. Twist and wiggle the seatpost using the saddle for leverage, untill it sticks fast again. repeat the process. it is slow and you will use many kettle fulls of hot water, but eventually the seatpost comes free, 1-2mm at a time. The carbon and the alum have different co-efficients of expansion. Took me over 4 hours but I got it out and didnt have to cut anything.Clean out the seat tube, removing any grease/wax left behind.DO NOT LUBRICATE YOUR SEATPOST/SEAT TUBE CONECTION WITH GREASE! it turns waxy after a while and then the seatpost gets stuck. Make a habit of removing your seatpost every once in a while to make sure the same doesnt happen again. Edited October 4, 2012 by Li Mu Bai Link to comment Share on other sites More sharing options...
Sawdust Posted October 4, 2012 Share I used Coke. Frame upside down. Filled with coke, left in the shower overnight. Fitted a saddle and it came loose. Link to comment Share on other sites More sharing options...
FrankTank Posted October 4, 2012 Share Fortunately, aluminum oxide can be dissolved like magic by using ammonia. Worked twice for me in the past. Submerge in ammonia for a day or two. http://sheldonbrown....-seatposts.html Edited October 4, 2012 by FrankTank Link to comment Share on other sites More sharing options...
Vetseun Posted October 4, 2012 Share Wont some spook piss make it come loose? Link to comment Share on other sites More sharing options...
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