Sanding the blank

[Santafecino]

Folks,
I've heard here and there about accomplished rod makers sanding the glued-up blank to modify the taper. I'm aware that one must sand off the glue that stuck when the blank was glued up, but I'm talking about something different: Sanding to change the taper. Is this considered acceptable? I would think this would take away the power fibers and weaken the blank. If it is acceptable, what are the ground rules? What sandpaper would one use, and what is the most bamboo one can safely remove?

Welcoming everyone's ideas,
--Santafecino

[Mike McGuire]

Back up a little bit an consider what we are trying achieve with a taper design. My answer is a particular distribution of stiffnesses along the rod. If due to variation in bamboo, error in construction etc. it is too stiff at some point, then it can be reduced by sanding around that point. One must keep in mind that stiffness varies as the 4th power of the cross section dimension, so it it very sensitive to dimension. It is perhaps even more sensitive than just this simple geometric effect due to the way power fibers are distributed, denser towards the surface. Thus a small amount of sanding is likely to have the desired effect. If a large amount of sanding is required, biting deep into the power fibers then it would be better to scrap and start over. I have never felt the need to doing this so I have never tried it.

Mike

[trouttrapper]

I did a lengthy treatise on this a few years back. You might want to look it up. My short version is NO! Do a proper job with your planning and you won't have to worry about sanding the power fibers to meet dimensions.
Lou B.

[kermit]

Ditto! No sanding of the glued up blank to meet taper dimensions.

[penta-spey]

I've done it during taper development on a rod that was not casting the way it was intended to.
The rod was heading for the scrap heap anyway so to test out a specific idea; I sanded the bottom half of the tip to certain specific dimensions I had in mind and wanted to test.

It looked like hell but I learned what I needed to know about that taper. Then scrapped the rod anyway.

I've heard people say this sanding is how some of the rod makers of old sometimes did taper design. You probably shouldn't sand very far doing this, but sometimes a little dimension change can mean alot to rod performance.

Even if the sanding produces a better casting rod; not sure you'd want to show anyone. Looks real bad once you sand even a little below the power fibers that sit just below the enamel.

[cdmoore]

What I have read and heard in discussions with folks with more brains and knowledge than I is that most sanding was used by the classic makers as a way to fine tune standard tapers to the needs of discerning and expert anglers who knew exactly what they wanted and had perhaps cast the standard version for comparison. It's one reason among several why different examples of the same rod model behave differently and why it is so important to buy the rod you have in your hands if you really like it rather than take a chance on another example at some later date.

As a rule of thumb, there is anecdotal evidence (Power Fibers, etc.) that a 4% change in dimension equals approximately 1 line weight, at least in the tip.

What kind of sand paper? Well, that depends. I wouldn't go below 150 grit. And leave some room for finer grits to finish. Also consider the finish. Oil finish might allow for an 800 grit surface finish, while varnish generally needs 150 - 220 to get proper adherence in my limited experience.

Hope this helps.

[Santafecino]

Well, I got the answers I asked for, and from a panel of experts, and in one day. Thank you all. I appreciate the contributions and have a renewed sense of the criticality of accurate planing.

[LeeO]

I wouldn’t sand to meet dimensions but I have seen quite a few older rods that were heavily sanded well past the enamel. They were still fishing so it didn’t harm anything

[chsparkman]

Holden's instructions in "Idyl of the Split Bamboo" include sanding to refine the action. I suspect there are more than a few rods still out there catching fish that were done this way. Of course now we have the capabilities to make accurately sized blanks so that old method should not be necessary. If, however, you are a hobbyist not selling your rods, why not try it with a blank that didn't come out as expected? If you damage it, you're going to make a replacement anyway.

[mrampant]

I have heard of some makers gluing up trial blanks with the enamel on the inside and then sanding to get a perfected action. This way the enamel is not compromised by making it thinner than it would have normally been. This would be for R&D purposes.
I don't know if this would help you for what you are asking.
Cheers,
Mark

[Bill Moschler]

I could see loading a rod for flex and doing just a little sanding to smooth the curve if needed.

[bluesjay]

Hi Guys, I could see perhaps sanding a spline to adjust for deflection. That is, sand a strong spline to weaken it so that all splines are the same. I may try it on some old tips.

Edit: Ignore the annoying line. Or, ignore the stupid idea..........

Jay Edwards

[BigTJ]

It works fine and it’s no big deal. It’s a time-proven method. No reason not to do it as long as you don”t go crazy with it.

[Godfroy]

From Cattanach, "Handcrafting Bamboo Fly Rods", Lyons Press paperback edition, 2005, page 103.

"Some inconsistency in dimensions - usually up to about 0.005 inch - can be corrected by sanding."

[jim royston]

Winston used to send surf cast blanks out to their "pros" and have them sand them to the desired action. Those sanded blanks became the template for production rods.

[nipigon]

It was written that Gary Howells sanded blanks to achieve final dimensions. (page 160, "Howells-The Bamboo Fly Rods and Fly Fishing Legacy of Gary H. Howells", Joseph H. Beelart, Jr.)