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#11
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Reasonable expectation...............
On Friday, September 15, 2017 at 7:30:42 PM UTC-7, John B. wrote:
On Fri, 15 Sep 2017 19:59:27 +0100, "Ian Field" wrote: "John B." wrote in message .. . On Thu, 14 Sep 2017 21:33:17 +0100, "Ian Field" wrote: "Joerg" wrote in message ... On 2017-09-14 10:42, AMuzi wrote: On 9/14/2017 12:32 PM, Ian Field wrote: The bike I built up on a frame I dragged out of a hedge has a seized seat post. So far; I've slackened the clamp bolt and give it a squirt of PTFE penetrating oil at least once a day - is there a reasonable expectation that it might work loose? Thanks. Yes. The vibration and cyclic loading of the post can free them. Not always but well worth a daily shot of penetrant and some miles. Leave the bolt out and cross your fingers! Might sing soprano after it let go all of a sudden :-) Its seriously stuck, it'll probably need a lot of twisting to shift it at all once it starts to loosen. If I still had a welder, I'd weld a lever arm to it so I could apply enough force. If it is an aluminum seat post in a steel frame and you can't budge it with a, oh say 24 inch pipe wrench, after a few days of penetrating oil then it probably won't come out without some serious attention. I once spent nearly a week to make a boring bar and boring out a stuck seat tube after all else failed however after reading the Internet I discovered that dissolving the aluminum tube using lye would have been much easier :-) No aluminium - and I wouldn't want a glob of corrosive **** running down into the BB bracket if there was. You are supposed to disassemble the bicycle before you start :-( From the Internet: As a strong alkali, sodium hydroxide will attack and dissolve the following metals: Tin, Aluminum, zinc, cadmium - behaves closely enough to zinc. It will also attack chromium plating and copper, although ammonia is far better at dissolving copper: The reaction with those metals releases hydrogen gas. Sodium hydroxide will not react with iron or steel, in fact the alkaline conditions will not allow rust to grow; What would you use in a frame that has been fully chromed? |
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#12
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Reasonable expectation...............
wrote in message ... On Friday, September 15, 2017 at 7:30:42 PM UTC-7, John B. wrote: On Fri, 15 Sep 2017 19:59:27 +0100, "Ian Field" wrote: "John B." wrote in message .. . On Thu, 14 Sep 2017 21:33:17 +0100, "Ian Field" wrote: "Joerg" wrote in message ... On 2017-09-14 10:42, AMuzi wrote: On 9/14/2017 12:32 PM, Ian Field wrote: The bike I built up on a frame I dragged out of a hedge has a seized seat post. So far; I've slackened the clamp bolt and give it a squirt of PTFE penetrating oil at least once a day - is there a reasonable expectation that it might work loose? Thanks. Yes. The vibration and cyclic loading of the post can free them. Not always but well worth a daily shot of penetrant and some miles. Leave the bolt out and cross your fingers! Might sing soprano after it let go all of a sudden :-) Its seriously stuck, it'll probably need a lot of twisting to shift it at all once it starts to loosen. If I still had a welder, I'd weld a lever arm to it so I could apply enough force. If it is an aluminum seat post in a steel frame and you can't budge it with a, oh say 24 inch pipe wrench, after a few days of penetrating oil then it probably won't come out without some serious attention. I once spent nearly a week to make a boring bar and boring out a stuck seat tube after all else failed however after reading the Internet I discovered that dissolving the aluminum tube using lye would have been much easier :-) No aluminium - and I wouldn't want a glob of corrosive **** running down into the BB bracket if there was. You are supposed to disassemble the bicycle before you start :-( From the Internet: As a strong alkali, sodium hydroxide will attack and dissolve the following metals: Tin, Aluminum, zinc, cadmium - behaves closely enough to zinc. It will also attack chromium plating and copper, although ammonia is far better at dissolving copper: The reaction with those metals releases hydrogen gas. Sodium hydroxide will not react with iron or steel, in fact the alkaline conditions will not allow rust to grow; What would you use in a frame that has been fully chromed? Aluminium reacts with both acids and bases, But chrome is safe from most alkalis. Some acids are particularly good at attacking chrome - I think there's a few that don't damage it much. |
#13
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Reasonable expectation...............
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#15
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Reasonable expectation...............
"John B." wrote in message ... On Sat, 16 Sep 2017 13:30:10 -0700 (PDT), wrote: On Friday, September 15, 2017 at 7:30:42 PM UTC-7, John B. wrote: On Fri, 15 Sep 2017 19:59:27 +0100, "Ian Field" wrote: "John B." wrote in message .. . On Thu, 14 Sep 2017 21:33:17 +0100, "Ian Field" wrote: "Joerg" wrote in message ... On 2017-09-14 10:42, AMuzi wrote: On 9/14/2017 12:32 PM, Ian Field wrote: The bike I built up on a frame I dragged out of a hedge has a seized seat post. So far; I've slackened the clamp bolt and give it a squirt of PTFE penetrating oil at least once a day - is there a reasonable expectation that it might work loose? Thanks. Yes. The vibration and cyclic loading of the post can free them. Not always but well worth a daily shot of penetrant and some miles. Leave the bolt out and cross your fingers! Might sing soprano after it let go all of a sudden :-) Its seriously stuck, it'll probably need a lot of twisting to shift it at all once it starts to loosen. If I still had a welder, I'd weld a lever arm to it so I could apply enough force. If it is an aluminum seat post in a steel frame and you can't budge it with a, oh say 24 inch pipe wrench, after a few days of penetrating oil then it probably won't come out without some serious attention. I once spent nearly a week to make a boring bar and boring out a stuck seat tube after all else failed however after reading the Internet I discovered that dissolving the aluminum tube using lye would have been much easier :-) No aluminium - and I wouldn't want a glob of corrosive **** running down into the BB bracket if there was. You are supposed to disassemble the bicycle before you start :-( From the Internet: As a strong alkali, sodium hydroxide will attack and dissolve the following metals: Tin, Aluminum, zinc, cadmium - behaves closely enough to zinc. It will also attack chromium plating and copper, although ammonia is far better at dissolving copper: The reaction with those metals releases hydrogen gas. Sodium hydroxide will not react with iron or steel, in fact the alkaline conditions will not allow rust to grow; What would you use in a frame that has been fully chromed? Well, not lye :-) Sheldon writes that "Fortunately, aluminum oxide can be dissolved like magic by using ammonia" however Brandt disagreed :-) I have no idea whether ammonia attacks chromium and "chrome plating" Ammonia is common in cleaning products - I've never noticed any problem using it on chrome plated fittings. I used to clean E-cigarette wicks by soaking in ammonia, the housing is stainless steel - there were no visible signs of corrosion. |
#16
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Reasonable expectation...............
On 9/17/2017 11:48 AM, wrote:
On Saturday, September 16, 2017 at 8:47:25 PM UTC-7, John B. wrote: On Sat, 16 Sep 2017 13:30:10 -0700 (PDT), wrote: On Friday, September 15, 2017 at 7:30:42 PM UTC-7, John B. wrote: On Fri, 15 Sep 2017 19:59:27 +0100, "Ian Field" wrote: "John B." wrote in message ... On Thu, 14 Sep 2017 21:33:17 +0100, "Ian Field" wrote: "Joerg" wrote in message ... On 2017-09-14 10:42, AMuzi wrote: On 9/14/2017 12:32 PM, Ian Field wrote: The bike I built up on a frame I dragged out of a hedge has a seized seat post. So far; I've slackened the clamp bolt and give it a squirt of PTFE penetrating oil at least once a day - is there a reasonable expectation that it might work loose? Thanks. Yes. The vibration and cyclic loading of the post can free them. Not always but well worth a daily shot of penetrant and some miles. Leave the bolt out and cross your fingers! Might sing soprano after it let go all of a sudden :-) Its seriously stuck, it'll probably need a lot of twisting to shift it at all once it starts to loosen. If I still had a welder, I'd weld a lever arm to it so I could apply enough force. If it is an aluminum seat post in a steel frame and you can't budge it with a, oh say 24 inch pipe wrench, after a few days of penetrating oil then it probably won't come out without some serious attention. I once spent nearly a week to make a boring bar and boring out a stuck seat tube after all else failed however after reading the Internet I discovered that dissolving the aluminum tube using lye would have been much easier :-) No aluminium - and I wouldn't want a glob of corrosive **** running down into the BB bracket if there was. You are supposed to disassemble the bicycle before you start :-( From the Internet: As a strong alkali, sodium hydroxide will attack and dissolve the following metals: Tin, Aluminum, zinc, cadmium - behaves closely enough to zinc. It will also attack chromium plating and copper, although ammonia is far better at dissolving copper: The reaction with those metals releases hydrogen gas. Sodium hydroxide will not react with iron or steel, in fact the alkaline conditions will not allow rust to grow; What would you use in a frame that has been fully chromed? Well, not lye :-) Sheldon writes that "Fortunately, aluminum oxide can be dissolved like magic by using ammonia" however Brandt disagreed :-) I have no idea whether ammonia attacks chromium and "chrome plating" is often several metals rather that just one so regardless of whether something did or did not attack chromium it might attack an underlying metal. Pinarello frames are often completely chromed under the paint. Somewhere there was a video of them using baking soda to allow rechroming. I know that the fork on the Pinarello I'm restoring was pretty badly rusted in places. The chrome shop perfectly restored it in one day. There are pin holes here and there but I can't remember any rechroming that didn't have those. Oddly enough the pin holes are not anywhere near where the rust was. Those areas are perfect. not 'baking powder' but rather reversed polarity in a caustic soda (lye) bath. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#17
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Reasonable expectation...............
"Joerg" wrote in message ... On 2017-09-14 10:32, Ian Field wrote: The bike I built up on a frame I dragged out of a hedge has a seized seat post. So far; I've slackened the clamp bolt and give it a squirt of PTFE penetrating oil at least once a day - is there a reasonable expectation that it might work loose? If it's a steel frame and steel post probably not. If both aluminum, maybe. Other tricks: Stand the bike on its head and let penetrating out run from the BB area down inside the seat tune. Let it sit like this for days. The drain hole in the BB tube could suffice to get the oil in there without having to remove the BB (if that ever comes out). Can't remember how much grease I packed in the BB housing - that trick might not work. Last time i posted it was totally stuck solid. last night I was able to force it round just a little bit - Can't be 100% certain the seat clamp wasn't turning on the post, but I tightened the clamp as hard as possible last time. |
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