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I find that after the initial fitting of my ferrules that they "grow". That is, increase in size so that the initial fit is now too tight.  For example, the ferrules on the rod I'm finishing were installed 12 days ago with 24 hour epoxy,  Twenty four hours later I polished them to a snug, full length engagement fit.  Today they would not fully engage and were too tight.  Does anyone know what causes this? . . . the epoxy expands? . . . the bamboo expands? . . . oxidization of the ferrules? . . . or a combination of these? (Ted Knott)

I suspect it was gremlins..  It is hard to conceive that the epoxy or the bamboo could expand sufficiently to cause this.  Too soon for oxidation to be much of a factor.    Have you considered temperature?   Then again it still might be gremlins.  (Ralph Moon)

The "growth" happens on every rod I make, so there has to be a rational reason for it.  Does this happen to anyone else on a regular basis? (Ted Knott)

Yeah, it happens to me pretty regularly and I have never known why.  So, now, I finish new ferrules for an easy fit, and within a few weeks they are nice and snug.  (Bill Harms)

Happens on every rod I've ever made. I had believed it is due to the cane reaching moisture equilibrium, but that doesn't explain John having the same problem out in Colorado. The only  other plausible explanation is the oxidation of the ferrules, but this seems a little too extreme to me.  Even .0001 oxidation is a huge amount of same, and I doubt we'd see this amount, or more, in such a short period of time. Epoxies don't typically expand, rather they might shrink ever so slightly, though most are dimensionally stable.

It's curious, and I've wondered about it, but now just accept it as inevitable, and plan on redressing the ferrules every time -- some times more than once.  (Martin-Darrell)

I just finished refitting a set of ferrules on one of my rods last night because of the same problem.  There seemed to be quite a bit of oxidization on both the male and female ferrules.  However, could it be that there is a correlation in the glue that is being used in the ferrules.  It could be that all the people that are experiencing the expansion may be using the same glue.  What glue is being used for those of us that are experiencing the expansion all the time?  Unfortunately, this rod was built a little while ago and I cannot be sure of the glue I was utilizing at the time.  (Robert Cristant)

I tend more towards the oxidation of the ferrule surfaces first, and then the expansion of either the adhesive or the cane.

When you think of a good fit on a ferrule it is close to .0002" to .0004"(2/10,000 to 4/10,000 of one inch) clearance from one to the other.  When thinking of the oxidation of a ferrule surface of even .00008" (80 millionths of one inch or 80/1,000,000 of one inch) you then double it to get the "growth" on both sides of the diameter, now double it again for the female or male.   So the .00008" film turns in to a .00032" "growth" which is about the fit for the two parts to begin with.

Or at least that is me spin on the subject.  (Brad Love)

You may be right.  I find a brief polishing with 3M 8000 paper nearly restores the fit.  (Ted Knott)

I have had the same problem, and I thought it might have been humidity.   I refit them again and the problem has not reappeared.  Happened to me in a humid period last year.  The rod was built and varnished and I did the fitting outside so as not to whack anything as I separated the sections. 

The next day they swelled up and I could not get the sections together.  refit them once again and the problem has not appeared since.   (Mark Babiy)

I don't think its humidity since it happens to almost every rod, IE over 50 rods in the past 3 years.  I've had rods which I thought were too loose a fit become "right" when left for a week.  (Ted Knott)

It happens to me too, even here in the 4 Corners, where we haven't had any humidity to speak of in ages. If anything, my ferrules should loosen, at least from the cane, after a while, but they don't, I still have to re fit them when the rod is done. Relative humidity here has been in the single digits in the afternoon for months.  (John Channer)

I believe it is entirely due to  the oxidization of the female ferrule. (Marty DeSapio)

Have had it happen a number of times. Suspect the ferrule problem is caused by the cane growing inside of the ferrule and causing it to push out slightly.  With my shop humidity to 40 > 45 % in the winter building season, the increase in humidity between that and summer conditions of 60>80% I suspect is the culprit. Cleaning the female doesn't help completely although I do remove a little oxidation each time. Seems like a light polish with diamond paper returns the fit to normal. Those that live in moist/soggy climates may never experience the problem.   (Don Anderson)

Soggy, moist climates don't help a bit.  I'm in Louisiana, and it happens to me on every rod.  Few places are significantly more humid than Winnsboro, Louisiana; although we can't be described as soggy right now, since we haven't had a decent rain since April.

I suspect that one factor none of us have mentioned may be the friction heat we apply to the ferrule when fitting it with fine sandpaper or whatever method we use.  Later, when things cool down, they return to size.

One interesting fact that may back up my suspicions is that the ferrules have grown on me in a matter of a few hours.  Fit 'em, wait two hours, and they won't fit anymore.

Your question spawns another... How tight do you fit your ferrules before you let that rod get out the door?  So tight you have to pop the veins out in your forehead when getting them apart?  So loosely you can separate the sections with two fingers?  Or somewhere between the two?

For the record, I like to say that proper ferrule fit requires about the same energy as fastening your belt a notch or two tighter than normal.....(Harry Boyd)

If heat is the cause, the male ferrule would expand, so when it cools it would be smaller, IE, a looser fit.  (Ted Knott)

I know that engineers tell us heat causes things to expand, and cold causes things to contract..... but I'm not so sure.  Ever put a Coca-Cola in the freezer?  The cold definitely doesn't cause THAT to shrink.  (Harry Boyd)

As far as male slides changing in dimension after being mounted on the blank, I think it is moisture entering or leaving the bamboo stabilizing to the ambient humidity. Had that very thing happen to me this morning. Two weeks ago the ferrules were an easy fit. After binding and dipping and trying the rod the male is undoubtedly a firmer fit than 2 weeks back. It's rained continually since I did the initial dressing. (Tony Young)

If the ferrules "grow" in a matter of a few hours, it seems that expansion of the epoxy is the most likely culprit. (Ted Knott)

I'm at a loss what causes the ferrule growing thing. As I usually make the ferrule fitting take a week or more. Polish/let sit/polish/let sit to make sure that oxidation in the female is accounted for + temperature changes from working the males + heat of compression of the air from the sliding the males in/out + the heat of my hands and all of which can cause a ferrule to be too loose.  I set the ferrules so that they are somewhat tight and reset them after a couple of weeks.  I know that a rod built in Florida and taken to Calgary, Alberta had the cane shrink enough that  the glue gave up between the male ferrule and the cane. The rod was assembled in a fly shop whose owner doesn't humidify the air. The percentage of humidity could have been less than 10%.  No idea how much it shrank. Was enough though to cause the male section to fall off.   (Don Anderson)

Here is another hypothesis to throw in the pot:

Maybe the nickel silver work hardens as all brasses do, and causes the female to be more resistant to expanding to accept the male slide and the male slide to be more resistant to compression. both components lose a bit of the elasticity that allowed them to slide together more easily when first fitted.

Any metallurgists out there?  (Steve Weiss)

Steve suggested one of the resident metallurgist answer this, and I contacted the only one I know, who wishes to remain anonymous. Here is what he wrote me in reply.

M-D,

Non ferrous metallurgy isn't my specialty!  That said I too have pondered over this question a few times and have always put the 'problem' down to one of oxidation! The reason being that Nickel Silver when left for a period of time in the polished state becomes dull, an indication of a surface passive film and almost certainly a low level of oxidation. Here endeth my ponderings.  (Martin-Darrell)

I tried an experiment after reading the first couple of posts on this thread.

I left my rod in the car all day and then went fishing, got real hot and ferrules fit together nicely. Yesterday and today I brought the same rod into my air conditioned office. the fit is much tighter. I haven't mic'd the ferrules yet but I would believe the hot and cold is having a greater effect on the male ferrule with the cane inside. I will try it again and bring my micrometer tomorrow.  (Peter Van Schaack)

So, how much do ferrules expand and contract with heat?? Is it possible that the heat generated by curing epoxy can cause the ferrule to expand? How loose is too loose? I have had ferrules on older rods so loose they would sometimes twist, but never come apart while casting. I have wondered if ferrules were installed while they were cold, would it expand and break the bond if the rod was left in a hot vehicle. So, should you heat set the adhesive when installing the ferrules and then do a final fit?

My ferrules usually get tighter after awhile also, I just clean them good with Isopropyl Alcohol and a Q-tip and polish the male with a shirt tail.  (David Dziadosz)

I have been following this thread close and there seem to be a lot of good answers. I can't believe oxidation is the real culprit. The reason being that I can have a set of ferrules that fit perfect before installing them on the blank. Glue the ferrules on the blank and try to fit them together in a couple of hours and they are too tight. Would there be enough oxidation in that short period of time.

One of the thoughts is the hydraulic action when installing the ferrules. I try to get a tight fit between the cane and ferrule, with just a small filed groove in  the cane to expel the trapped air. Many times I have to really push the cane into the ferrule with the end of the ferrule against the work bench. That does cause a lot of pressure on the walls of the ferrule. Would that pressure be enough to expand the male ferrule just enough to make it too tight. Pounding sand in a male ferrule to expand the walls work, why not pressure from installing the cane in the ferrule.  (Tony Spezio)

No, that can't be it, because I fit the ferrule after it is installed on the blank. In a week or two they are tighter. I am watching for this phenomena on my aluminum ferrules, and so far it hasn't happened. If it doesn't happen on them, then it is something about the properties of NS.  (Darryl Hayashida)

It doesn't happen to aluminum ferrules, or at least not in my experience with the ones I make for my rods.  If the aluminum did oxidize it would shrink and become looser in fit, not "grow" as nickel and zinc does when is exposed to air.  (Brad Love)

I don't fit my ferrules until they are on the blank, and they still grow too tight, not right away but after a month or so. They work fine for all the lawn-casting I like, but when I get to the stream they immediately misbehave.

I suspect the right answer to this is "All of the above;" meaning oxidation, humidity, glue expansion, and the koosey-oonik.  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

Mine was a theory that you just dispelled. I guess the hydraulic idea is down the drain.  I do fit my ferrules before gluing them to the blank. I just find it easier to do. One reason is, if I screw up I don't have to try removing the male. Another is I find it easier to handle the small ferrule than one that is attached to a tip section or butt section.

We all have our own ways of doing what works for us. The fact is, regardless of what  method or glue that is used there seems to be the same problem. Nice to know that I am not the only one that has it. LOL. Gremlins really working hard with the rodmakers.  (Tony Spezio)

I have had the same experience with ferrules fitting just right for a couple of weeks and then being tight enough to require redressing. I was of the opinion that it was a wicking action of the stick taking on moisture, but some of my sections have set long enough to be totally stable before putting on the ferrule.

I use Golfsmith epoxy, could this be a glue issue we are dealing with?  (Steve Trauthwein)

Frank -- believe me, it's the koosey-ooink.  Seriously, I have to think it is primarily moisture uptake.  I intend to use Plexi-soup at the ferrule station of my next rod to see if the malady continues.  If not, it will have to be moisture.  (Richard Tyree)

Then explain to me why my ferrules do exactly the same thing:  Relative humidity in Durango right now is 6% at 5 in the afternoon, it was 31% here at 6 this morning and my ferrules still need to be refit by the time I send a rod out, I first fit them the day after I mount then so I can test cast the rod before I go to the trouble to wrap it, then check them again before I ship it, invariably they are too tight and have to be sanded some more.  (John Channer)

The short answer is that I cannot explain it.  After reading yours and a couple of others, it is obvious there is more to this than meets the eye.  I recently used a set of Bailey Woods ferrules that had been in my shop for a couple of years.  Found  out after mounting them that they were a perfect fit right out of the box and was well pleased, only to be disappointed a few weeks later to find they were too tight.  Cleaning inside the female and the male helped, but not back to where they had been.  So why did they not oxidize while in the shop before using??  Guess I'll never know.  And for that matter, why do ferrules oxidize so fast in Durango with such a dry climate as it seems to me moisture should have something to do with the rate?

The strips for the above mentioned rod had been straightened and bound together and in the shop, also for a couple of years.  So, as a nod to Bob Milward, I put them in an air gun oven for over 3 hours at 220 degrees F, swapping end for end after one and a half hours.  They were bone dry (by weighing at 30 minute intervals, determined they no longer lost wt after 3 hours) so part of the answer must moisture intake.  I do keep my shop dry for the most part with around the clock heat and a/c as appropriate.

Still looks like moisture must have a part, but cannot prove it or say how much.

Here is another baffling example. Have a couple of rods made in the early 60's from Orvis blanks.  One of the rods had a bit of a loose fit which was adjusted out by Orvis.  Stopped in at the Orvis plant in 1965 and watched a crusty old guy take a small rubber or plastic mallet and tap, tap, tap, tap until he got it right.  The ferrules on that rod and the other have not changed a bit in all these years.  Impregnation have anything to do with it??  Why no oxidizing ??

So, guess it is still a big mystery here.  (Richard Tyree)

Ps -  Still plan to do the Plexi-soup test, but it will be winter before it can be done.  In the meantime, if anyone gives it a try before then, please let us know the results.

Maybe I can help reduce some of the variables in this phenomena: I use only contact cement for securing ferrules and I do have the problem. So it's not only epoxy etc.  I also use very little installing heat so heat might not contribute to the problem. I do hand-fit my ferrules very tightly, with a heavy push to seat them on the cane. Have a feeling that this does contribute to the problem. I have a recollection that when I built with pre WWII cane there was no such problem.  Any help?  (Bill Fink)

Based on what you're saying it sounds like the glue may be making the "green"  (don't ask me where  the cutoff on seasoned and green is, I'm still struggling with that one myself) cane swell. I will add that on the production rods I've redone with new ferrules I haven't experienced this. What about other guys that have done restoration work, are they seeing this on older cane rods as well?  (Bill Walters)

To the list, has anyone ever fitted a ferrule dry, then glued it and and it not fit.  I spent allot of time making sure it was correct and after gluing it, it was .005 larger on the male end.

No comprende?  (Stuart Miller)

This happened to me on a 3 piece rod with aluminum ferrules.  My diagnosis is that the cane absorbed moisture from high humidity.  After I left the rod sit for a few days inside with air conditioning, the sections came apart, but then I took a couple thousandths off to eliminate the problem  -- after I broke the mid section while pulling too hard.  (Paul Franklyn)

Is it possible for cane to absorb enough moisture that it actually increases the diameter of the male ferrule?

I've always tried to get the cane really dry before gluing on the ferrules, but some get really tight after wards, and it seems most noticeable when I'm camped by a river in humid weather.

No, I've not thought to measure the ferrule diameter pre- and post- trip.

Any thoughts?  (Henry Mitchell)

Absolutely.  Bone dry bamboo 0.200 diameter will expand about 0.004 – 0.008  depending on your ambient humidity.  This in turn will cause your male ferrule to expand some, too.  I haven’t measured the expansion of the ferrule though.  I’d guess about 0.0005 inches but that’s about how much clearance you leave on a properly fitted set.  So, yeah, it’ll get tight!  (Al Baldauski)