1992 Saracen Kili Racer
- Thread starter spatuluk
- Start date
Pouring in, more like.coomber":3jgc7dmi said:
Due to having no good way of getting the caustic soda in through the BB hole, the frame was upside-down with the seatpost, and as much frame as possible, dunked in a bottle of caustic soda that was sitting on the ground. My vague thinking was that it might dissolve enough around the seatpost to let some penetrating oil in, but I didn't realise it'd produce aluminium oxide. Hopefully the oxide didn't actually make the seatpost wider inside the frame. :?
If I can get a funnel on the way home, tonight's attempt will also be done upside-down, with the seatpost bunged and filled up with 50/50 caustic soda. I wonder how much liquid it takes to fill a seatpost..
edit: I keep thinking that I'm applying the caustic soda pre-mixed, and can't allow spillages or contamination, but I could just pour in some water using any old thing, then carefully spoon in the powder afterwards. No need for funnels!
If you do it upside down like I did, then I think about a litre but if its strong enough (add the powder to water not the other way around!) it will soon start frothing back through the BB so you will know you have enough in there, plus for you, the post is at the top so you will need less (mine was right down by the bottom bracket).
Nothing with the caustic soda can jam that seatpost in any more, steel and aluminium expand at different rates.
If you are going to use caustic soda, why not hack the seatpost off an inch above the seattube, as it will be easier to bung then using the round top of the post as it is?
Nothing with the caustic soda can jam that seatpost in any more, steel and aluminium expand at different rates.
If you are going to use caustic soda, why not hack the seatpost off an inch above the seattube, as it will be easier to bung then using the round top of the post as it is?
Mainly because I'm lazy, but also because the wife's already unimpressed with the amount of time I'm spending on trying to fix up my bikes. :roll:coomber":15e6pkx8 said:
I spent hours on the Courier (to no avail, so far - bloomin bottom brackets!!), I spent hours on the ALX89 (now technically working, but rides really badly - can't work out why), and so now I'm trying not to spend too many hours on the Kili. Applying dangerous chemicals is okay, because it only takes half an hour tops.
spatuluk":3rdc760h said:Mainly because I'm lazy, but also because the wife's already unimpressed with the amount of time I'm spending on trying to fix up my bikes. :roll:coomber":3rdc760h said:
I spent hours on the Courier (to no avail, so far - bloomin bottom brackets!!), I spent hours on the ALX89 (now technically working, but rides really badly - can't work out why), and so now I'm trying not to spend too many hours on the Kili. Applying dangerous chemicals is okay, because it only takes half an hour tops.
All fair enough!
Well keep us updated!
Re:
Tonight was a bit of a fail.
I started off by sticking blutac into the two holes in the seatpost, and taping them down. Then I taped a bin liner around it to try and catch drips.
I filled a 500ml soda stream bottle with water, taped up one side of the BB shell to stop the water pouring out, and slowly poured the water in. Weirdly, it took less than 500ml to fill the post, which doesn't seem right..
To get the caustic soda into the frame, I used an old baby spoon and spooned it in. After maybe 70g, it started fizzing out of the BB. I kept adding powder, and then tried to seal it with a blob of blutac. I don't think it sealed very well, but it hardly mattered because the seatpost seals had also failed, and the caustic soda had melted through the bin liner. :facepalm:
So, I don't think I dissolved much seatpost tonight. Maybe I'll have to hacksaw the seatpost after all. :|
Tonight was a bit of a fail.
I started off by sticking blutac into the two holes in the seatpost, and taping them down. Then I taped a bin liner around it to try and catch drips.
I filled a 500ml soda stream bottle with water, taped up one side of the BB shell to stop the water pouring out, and slowly poured the water in. Weirdly, it took less than 500ml to fill the post, which doesn't seem right..
To get the caustic soda into the frame, I used an old baby spoon and spooned it in. After maybe 70g, it started fizzing out of the BB. I kept adding powder, and then tried to seal it with a blob of blutac. I don't think it sealed very well, but it hardly mattered because the seatpost seals had also failed, and the caustic soda had melted through the bin liner. :facepalm:
So, I don't think I dissolved much seatpost tonight. Maybe I'll have to hacksaw the seatpost after all. :|
I was hoping to get a photo this morning, but it was a mess of melted bin liner, and I had to go to work before I could get it all off.
I still don't have the time to hacksaw the post, so tonight I'm gonna have another go at bodging it instead. What could possibly go wrong? :roll:
As the tonic water bottle resisted the heat the other day, I'm going to use a cut up 500ml soft drinks bottle to encase the seatpost. If I use a big blob of blutac as a sort-of gasket between the frame and the bottle, and a tie wrap or jubilee clip to hold them together, then it might resist the caustic soda. At the very least, the bottle will hold enough caustic soda to keep the end of the post dissolving if the gasket fails. I've got a 1 litre bottle to catch anything that does escape. And a bucket under that. I'll also attempt to plug the holes in the seatpost, like I did yesterday, but this time I won't use duct tape to hold it in place (I think it melted) - I'll use tie wraps.
So, I reckon plug failure, gasket failure, then bottle failure due to the increased heat level. It's a good job we weren't planning to plant anything where I'm doing this!
edit: after reading that back, hacksawing the post might actually be quicker...
I still don't have the time to hacksaw the post, so tonight I'm gonna have another go at bodging it instead. What could possibly go wrong? :roll:
As the tonic water bottle resisted the heat the other day, I'm going to use a cut up 500ml soft drinks bottle to encase the seatpost. If I use a big blob of blutac as a sort-of gasket between the frame and the bottle, and a tie wrap or jubilee clip to hold them together, then it might resist the caustic soda. At the very least, the bottle will hold enough caustic soda to keep the end of the post dissolving if the gasket fails. I've got a 1 litre bottle to catch anything that does escape. And a bucket under that. I'll also attempt to plug the holes in the seatpost, like I did yesterday, but this time I won't use duct tape to hold it in place (I think it melted) - I'll use tie wraps.
So, I reckon plug failure, gasket failure, then bottle failure due to the increased heat level. It's a good job we weren't planning to plant anything where I'm doing this!
edit: after reading that back, hacksawing the post might actually be quicker...
Day 3:
Last night, I cut off the bin liner and removed the blutac from the seatpost. It turns out that the seal failure wasn't the blutac, after all - it was a new hole in the seatpost!
The new hole was between the two others, so I stuffed a load of blutac in through the standard holes, and pushed it down using the new hole. I also used a couple of tie wraps to keep the blutac in place. That ought to keep most of the caustic soda in! I put the end of the post into the 500ml bottle, added water, and spooned in the soda powder. Again, it started fizzing out of the bottom bracket, and the pressure kept blowing my blutac out of the hole. Luckily, I found a perfect sized bung - a tiny apple that'd fallen off of next door's tree! With that jammed in, everything seemed to be staying inside the frame, so I placed the pallet over it, blocked the sides with a couple of bike wheels (my cat still has a nose, so it must work), and let the caustic soda get on with things.
This morning, the apple had fallen out, and the caustic soda had escaped. I don't think it escaped via the seat post - it seems to have escaped via a breather hole in the jutting-out part of the top tube. That means it's eaten it's way through another part of the seat post!
I didn't have long before setting off for work (as usual), so I just added water, added soda powder, jammed in another apple, and went to work. It will leak out, but every little helps!
Last night, I cut off the bin liner and removed the blutac from the seatpost. It turns out that the seal failure wasn't the blutac, after all - it was a new hole in the seatpost!
The new hole was between the two others, so I stuffed a load of blutac in through the standard holes, and pushed it down using the new hole. I also used a couple of tie wraps to keep the blutac in place. That ought to keep most of the caustic soda in! I put the end of the post into the 500ml bottle, added water, and spooned in the soda powder. Again, it started fizzing out of the bottom bracket, and the pressure kept blowing my blutac out of the hole. Luckily, I found a perfect sized bung - a tiny apple that'd fallen off of next door's tree! With that jammed in, everything seemed to be staying inside the frame, so I placed the pallet over it, blocked the sides with a couple of bike wheels (my cat still has a nose, so it must work), and let the caustic soda get on with things.
This morning, the apple had fallen out, and the caustic soda had escaped. I don't think it escaped via the seat post - it seems to have escaped via a breather hole in the jutting-out part of the top tube. That means it's eaten it's way through another part of the seat post!
I didn't have long before setting off for work (as usual), so I just added water, added soda powder, jammed in another apple, and went to work. It will leak out, but every little helps!
Re:
Not much to add tonight - I've run out of blutac, and one of my gloves has got a hole in it, so all I've done is hacksaw off the end of the post.
Have some photos, instead!
Mucky business, dissolving a seatpost! Here's my amazing hacksaw work:
This is all that was left of the top of the seatpost:
Can't really tell how much there is left to get rid of:
Not much to add tonight - I've run out of blutac, and one of my gloves has got a hole in it, so all I've done is hacksaw off the end of the post.
Have some photos, instead!
Mucky business, dissolving a seatpost! Here's my amazing hacksaw work:
This is all that was left of the top of the seatpost:
Can't really tell how much there is left to get rid of:
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