Re:
Well, to stop an AL shim in a Ti frame from bonding you would use copper paste. The
copper paste limits galling, and thus prevents oxidation damage (https://en.wikipedia.org/wiki/Galling).
If you were to insert say a wrong size shim and seat-post dry in the Ti frame (I assume there will be some trial and error going on to select the right shim) and tighten the whole thing up with no lubricants the chances of getting things stuck is high.
To be clear, there is actually no reason whatsoever that the shim should be bonded in the frame; it would only limit your seat-post selection. I've got three frames with "loose" shims (steel and AL) with
no problems.
To stop an AL seat-post bonding to an AL shim, any old grease would do.
To stop a steel seat-post bonding to an AL shim, any old grease would do.
To stop a Ti seat-post bonding to an AL shim, again use copper paste.
To stop a carbon seat-post post bonding - or rather slipping in an AL shim, a specific paste
is required that actually increases friction but does not contain damaging oils to the carbon
fibre coating surface.
Another alternative is a plastic shim, where in theory it would not need any lubricants. But this
is retrobike. We are metal heads. We can't tolerate plastic on bicycles....you know, reflectors
and spoke protectors etc. etc. etc.
Well, to stop an AL shim in a Ti frame from bonding you would use copper paste. The
copper paste limits galling, and thus prevents oxidation damage (https://en.wikipedia.org/wiki/Galling).
If you were to insert say a wrong size shim and seat-post dry in the Ti frame (I assume there will be some trial and error going on to select the right shim) and tighten the whole thing up with no lubricants the chances of getting things stuck is high.
To be clear, there is actually no reason whatsoever that the shim should be bonded in the frame; it would only limit your seat-post selection. I've got three frames with "loose" shims (steel and AL) with
no problems.
To stop an AL seat-post bonding to an AL shim, any old grease would do.
To stop a steel seat-post bonding to an AL shim, any old grease would do.
To stop a Ti seat-post bonding to an AL shim, again use copper paste.
To stop a carbon seat-post post bonding - or rather slipping in an AL shim, a specific paste
is required that actually increases friction but does not contain damaging oils to the carbon
fibre coating surface.
Another alternative is a plastic shim, where in theory it would not need any lubricants. But this
is retrobike. We are metal heads. We can't tolerate plastic on bicycles....you know, reflectors
and spoke protectors etc. etc. etc.
