integerspin
Senior Retro Guru
I have no idea what 10% is like, I add caustic till the water gets hot.
Add a bit at a time, otherwise the water will boil and it will try and escape.
I use it for removing aluminium from steel, like ali on a bore wall after seizing an engine. Only time I have used it on a seat post was a month or so ago. The frame had been full of thinners and atf for a month and the tube still wouldn't move.
I filled the seat tube half way, it got pretty hot and steamed a lot, about an hour later it had cooled down, so I emptied it and put a new batch in. After about half an hour I realised it was pouring out of the seat post. I grabbed the seat post and it came out really easy. The post is thin like foil, the post is complete but very thin, with a hole where the caustic went though it. The seat tube will get hot and it might affect the paint, if thats a problem don't mix the caustic as strong, or water it down when it goes above touchable[I have always thought that was about 70ºC]. You can just see a paint mixing cup in the lower right of the picture, I was mixing the caustic hot enough to distort the cup. I used about half a little pot of caustic.
Where the caustic is running down in the pic, it's running out of the hole it made. The bloke I bought the frame from had a neat idea, a mag drill bit with a pilot. He bores most of the post away, it then pulls out by hand. He wanted to remove it, I wanted to leave it to soak[I am a cheapskate and wanted to reuse the post]. I have soaked vintage bike parts that look like they have been in a ditch for 70 years, leave them long enough and they always come apart. I would have left the frame longer but I was going to assemble it and use it, which I haven't done.
Add a bit at a time, otherwise the water will boil and it will try and escape.
I use it for removing aluminium from steel, like ali on a bore wall after seizing an engine. Only time I have used it on a seat post was a month or so ago. The frame had been full of thinners and atf for a month and the tube still wouldn't move.
I filled the seat tube half way, it got pretty hot and steamed a lot, about an hour later it had cooled down, so I emptied it and put a new batch in. After about half an hour I realised it was pouring out of the seat post. I grabbed the seat post and it came out really easy. The post is thin like foil, the post is complete but very thin, with a hole where the caustic went though it. The seat tube will get hot and it might affect the paint, if thats a problem don't mix the caustic as strong, or water it down when it goes above touchable[I have always thought that was about 70ºC]. You can just see a paint mixing cup in the lower right of the picture, I was mixing the caustic hot enough to distort the cup. I used about half a little pot of caustic.
Where the caustic is running down in the pic, it's running out of the hole it made. The bloke I bought the frame from had a neat idea, a mag drill bit with a pilot. He bores most of the post away, it then pulls out by hand. He wanted to remove it, I wanted to leave it to soak[I am a cheapskate and wanted to reuse the post]. I have soaked vintage bike parts that look like they have been in a ditch for 70 years, leave them long enough and they always come apart. I would have left the frame longer but I was going to assemble it and use it, which I haven't done.
