How long should a tip-top tube be to offer best strength before it just produces unnecessary weight?

I assume you mean how long does it need to be to offer enough adhesive surface so that it's not likely to come loose. Well, only about half of the length you see on most tops. However, owing to the wide variety of adhesives used, whether or not the builder (custom or commercial) properly preps the blank tip, inside of tiptop, etc., etc., etc., the makers seem to have added additional length for good margin of error in mounting. In other words, it really depends on how good of a job you do in mounting it.

You could remove about half the tube, use 5-minute epoxy, properly prep everything and not likely ever see a tiptop come loose. But the weight savings would be minimal. On larger tiptops, sure you'd save more weight, but the blanks they're intended for are fairly powerful to begin with and wouldn't likely show much benefit from such weight reduction.

Good question, though.

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Is your question in regards to fly, spin or bait casters? And what strength are you inquiring about - adhesive strength to the blank or something else?

If you are asking with regard to fly rod tip tops separating from the blank, think it far more important to prepare the blank tip and to fill the tube with glue or adhesive than is the tup top tube length. Don't build enough spin or bait cast to know for sure, but suspect it is true for them too.

Frankly, if a knot or kink fouls at the tip top, I'd rather the tip top separate from the blank than for the blank to be at risk.

How exactly does one prepare the rod tip? The videos I learned from just put the adhesive in the tip top and slide it on. Should I be sanding the rod tip or something else? Thanks!

Drew

The process you describe works and works well enough. Some of us take a couple extra steps, the first of which is to clean a blank, including the tip, with a solvent. I use plain old rubbing alcohol on a soft cloth. If you're using an epoxy adhesive you can go for a water break free surface prep (See Surface Preparation in the Library.), but you've got to be VERY careful not to get carried away. I usually tape off the tip top area, VERY, VERY LIGHTLY sand with 400 grit paper and call it a day. If you have small riffle files a quick filing will rough the tip top tube interior.

Again, your process works. I've slapped tip tops on a bunch of gloss blanks with no prep other than cleaning with only a couple adhesion failures which might have been more rod storage temperature or other issues.

Any thoughts on what is too short with respect to breaking the tip of the blank in bending? I interpreted the original question in that direction. On some blanks the bending stress would be almost negligible due to the tip pointing at the lure, but on stiffer ones, that is not the case. If you consider having a tube length of about 1/8 inch, that clearly would be too risky. At what length does the risk become low enough to be negligible again?

I think this whole issue is a wasted worry considering the very small mass that might be saved.

Michael

Don't know with certainty the answer to your question, but suspect this is one of those counter intuitive things where it might be the longer tube associated with more risk instead of the shorter tube.

Regardless, the tip top is guide #0 and ought to be considered its relationship to guide #1. If guide #1 is severely out of position down the blank, it seems unlikely a longer tip top tube would save the day and perhaps make a bad situation worse.

Michael: I was thinking about the degree of perfection in strength and application of adhesive - longer tube, less critical - but your speculation about a short tip-top tube leverage causing breakage is food for thought. Agree that weight of 20 wraps of thread or a couple millimeters of tip-top tube are beyond human sensation.

Phil,
I normally target at 6 to 7 times the blank dia.
I fill the tube with adhesive and scrape off the excess after application.

Gene