Galt

Following the above advice should eliminate contamination as the cause of the problem. If the problem persists, could it be that the finish is not receiving a complete scuffing? Flat sanding sticks are great for flattening 'nibs' and leveling high spots, but may not be covering the entire surface. synthetic steel wool (000), I find, works well for scuffing all of the surfaces. It can reach under guides and flow over wraps. It can even soften the sharp vertices, helping the finish to flow over them. Since polyurethane finishes have been notoriously poor at bonding to themselves, it is very important to give an aged surface a complete scuffing.

Something else to consider is that since these finishes cure from the surface inward, scuffing the surface exposes semi or un-cured finish to the atmosphere. This should be good for adhesion of a second coat. However, If the entire film was not fully cured at the time of scuffing and then was left for a few days before re-coating, that scuffed surface would then become a 'new' cured surface with the same limitations of adhesion and need for scuffing It would seem prudent, then. to re-coat shortly after any scuffing.

Galt

0       0.109

5       0.130

10       0.139  

15       0.155  

20       0.166  

25       0.180      

30       0.190      

35       0.213       

40       0.230      

45       0.247        

50       0.271      

55       0.296        

60       0.322        

65       0.346        

70       0.358        

75       0.371        

80       0.384        

85       0.397        

90       0.410        

95       0.422        

96       0.425      

If you will, have a look at this taper built as a 3 piece for a 10 wt. line Quite powerful with some flex down into the butt. It is nothing like your original intent though.

Galt

Chris,

If I may, the method of using a block plane you observed from the carpenters is how you might employ one when faced with stubborn end grain at 90° to the plane sole. It creates a very effective and acute slicing cut as opposed to the shearing cut you would get running the plane parallel to the direction of the cut. The slicing cut severs the end grain with less force. Sometimes a low angle block plane would be employed in the same situation.

When you plane bamboo, you are planing parallel to the 'grain'. Since you are not trying to sever the fibers at 90°, a slicing cut is usually not needed--though it does no harm. Planing at 99° to the forms, I would think, would require the use of both hands and thus might be more cumbersome. Because the 'grain' is in many directions at the nodes, as Harry mentioned, it can be advantageous to skew the plane slightly if they have a tendency to tear.

In my opinion, over time, I think you will find planing to be less fatiguing if the plane is held slightly askew to or parallel to the direction of the cut. If conditions dictate more skew angle, then so be it.

Galt

Really, that's very interesting. So, a 50 year old rod would have a different amount of moisture than a bamboo strip that's been heated and dried?

Yes, but I think the operative word should be 'could' have a different moisture content. The only thing that is relevant is the difference( if any) between what it was when built compared to when it was repaired. Turning a ferrule station to just over what could be pressed on by hand , heating the station to drive off moisture, hence shrinking the cane just enough for a very tight press fit, would result in a very tight fitting ferrule joint. The cane would eventually acquire more atmospheric moisture in order to approach an equilibrium making for an even tighter fit.

Galt

I will suggest that the main causal factor to be moisture. If the moisture content of the bamboo has increased from when the ferrules were originally set, the resultant swelling of the cane could cause more holding force against the metallic ferrule. Once removed from the restraint of the ferrule, the cane can now expand to a diameter greater than the ID of the ferrule.

Galt