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Heat Treating - Sets

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A couple months ago, August to be exact I was in Montana casting flies - stopped into a fly shop (I forget the name) but picked up and handled a Thomas and Thomas cane rod $3,000 worth -  I've been interested in this whole tempering subject for some time now since I'm basically new to all this - so I flexed this T&T rod very mildly like I had a  2 LB trout on for about 15 seconds -  low and behold that cane rod took a heavy set -- so discouraging ---   the question to you all if you don't mind is I wonder how many of you have tested your tempering processes to see if the rods take sets or not as I've been told by a particular rodmaker (no name mentioned) that he promises me that his rods can be bent like a 10 lb trout on for many minutes and his rods will spring back straight as an arrow - and for the record can you tell me what your tempering process is - "time and at what heat "    (John Silveira)

A cane rod is more likely to take a set from bending in the dead of summer then in the winter due to moisture absorption from a higher humidity level. That is why when playing a fish it is recommended that one turns the rod over to equalize things.  (Marty DeSapio)

One can also protect a rod by aiming the tip rather outward toward the fish and lifting with the butt area.  This saves a rod by letting the stronger wood do the work and avoiding that sharp bend in the upper third.  The only "disadvantage" is that you need a good hand on the reel since you aren't quite as free to wave the whole rod around at right-angles to the fish. Takes a little practice.  (Bill Harms)

Rods subjected to an inordinate amount of moisture in the form of humidity can, even through varnish, accrete enough internal moisture to take a "set" relatively easily. It may be that T&T is responsible. But, I wouldn't be too quick to blame poor workmanship on their part. I might have been that the rod was stored for several months in  a place that was much too damp.

And yes. I've tested my tempering process. It seems that the tempering that goes right to the brink of "cooking" the strips is the best. A very dicey process.  (John Zimny)

I doubt the T&T rod you tested was faulty because of inadequate heat treating.  Instead, the culm itself should never have been used.  A stout flexing of the internodal fibers before one builds is what's needed.  Take a typical strip from EVERY culm you split and flex-test between each node, because even the very best looking cane can have a weak area.  This almost never occurs through the full length of a culm, but only between one set of nodes.

No amount of heat treating will cure a bad area, and if the culm is used to build a rod, you will get results of the sort you saw in that Montana fly shop.  You can bend the rod this way and that, and the rod will want to retain that bend.  It's not a "set" in the ordinary sense of the word.  It's worse.  A "set" rod probably still has its structural integrity, but a rod built of faulty cane never had it in the first place.  (Bill Harms)

I have found a couple of reasons for a rod to take a set. One is the glue did not bind well in the area and the cane is allowed to move  at the joint. Another is the cane is not good enough and is weak. Still another is that the heat treating did not change the cell structure enough to remove bound water and the cane is holding onto moisture. While it is true you can not remove moisture permanently it is important to heat treat enough (in most cane) to change the cell structure.

If the set is due to moisture drying the rod will eliminate the bend for a while but it will return as the moisture is reabsorbed. If it is from faulty glue or cane it will always take a set no matter what remedy you try.

I have done my share of experimenting with heat treating. What I have come up with is that while an oven can work fine you really do not know what the temperature is. It is akin to smoking a brisket. You can smoke a brisket for 20 hours at 200 degrees and your briskets internal temperature  never comes close to that temp. So it is with the cane.

I get the best results using a big garden torch on a culm heating and turning watching for the drying crack to expand and controlling color. You can monitor every inch of heat treatment  at all times and at no time is the cane blacken or burnt. Using this method you have total control of the heat treating process and do not have to worry if the cane is getting even heat. You just have to know how to do it right.

This has eliminated any and all heat treatment problems with cane and a plus is you always have spare strips already heat treated if the need arises.  (Adam Vigil)

When you say garden torch, are you still talking propane? And, what kind of head on the nozzle are you using? I like this idea and want to explore it further, myself. So, any more details on your process would be helpful.  (Bill Walters)

I too like this idea.  I did a search in the archives and found this, originally posted by Adam:

Since flaming is such a skill and the technique varies due to distance, heat and time I will tell you what I have observed. Taking into account that the culm is fairly dry and the split is about 1/4 wide or so this is the technique Jim Reams showed me and others at the Bishop Gathering. Using a garden torch with the culm placed on the ground supported to keep it a few inches above the ground. The garden torch, which sounds like a jet, is held about 7" above the cane and is passed from end to end with moderate speed. The culm is rotated and the passes from end to end are repeated. This is done over and over until the whole culm has been subjected to the flame and the drying split is now about opened 1". The time elapsed for a 6' culm is 7-8 minutes. There is no burning of the  enamel and the color is a light caramel. If highlights are wanted a small torch is used to add them in. This flaming method requires no added heat treatment. (Adam Vigil)

I just ordered my torch from Lee Valley.  SWMBO wanted one anyway for weeding.  (Bill Benham)

That is pretty much the procedure. I have found that the time cane vary depending on the amount of color change wanted. Each pass of the torch should make a slight change only. The cumulative change in color at times has taken 20 minutes per 6' section. It all varies on the heat of the torch as well as the distance between torch and culm. The whole concept is to move the torch torch with a slow steady wave of the hand from one end to the other then do it in reverse rotate culm and do the next area, repeat until color change is achieved. You  are not limited to one rotation of the entire culm. 2 rotations probably be the limit. The speed and rate of the torch needs to be steady and even. The good thing is you are in control and can speed up or slow down as need to treat a culm. Monitoring the drying split you can determine if even heating is occurring. When all is done the split should have approximate gap for the length culm.  (Adam Vigil)

A couple of years ago, I posted a message about a mystery set in a tip section.  One tip section of a two-tip rod was straight when I glued it up, but by the next day it had developed a very pronounced set.  The set was really persistent and required several attempts over about a week to finally remove it, and neither I, nor the list, could come up with an adequate explanation for what caused the set in the first place.  Well it happened again, and this time I figured out the cause.

I recently glued up a 3/2 rod and one tip section developed a sweeping set that put the center of the section about an inch off a straight line connecting both ends.  This tip section was perfectly straight the day before, when I took it out of the binder and hung it up.  I had rough planed and heat treated all the strips a couple of weeks before final planing.  During final planing, I discovered a flaw in one strip, and had to discard it.  Fortunately, I had some spare strips from the same culm, and I cut one to length, straightened the nodes, roughed it out, heat treated it, and had it planed to final dimensions in less than 2 hours. That replacement strip had a blemish on it, but it was in the waste that I was going to cut from the butt end of the tip section when I cut it to length, so I wasn't worried about it.  I was pretty pleased with myself, and I went ahead and glued up the rod.  When the mystery set appeared the next day, the blemish made it obvious that the replacement strip was on the outside of the curve.

In the two weeks that the original strips sat around after heat treating, they had come to equilibrium with the ambient humidity in my shop.  The replacement strip had no moisture in it at all.  After glueup, as it absorbed moisture, it swelled.  I expected this, but I had always heard that wood was stable in length and only really swelled and contracted in width with changes in moisture content. Besides, I dampen my strips before gluing with PU, and I expected that this would help equalize the moisture content.  However, when you are dealing with strips as small as the splines in a tip section, and they are glued together, it takes very little differential movement to produce a substantial set.  I'm almost certain that the same thing happened to cause my previous mystery set

The solution is really simple:  when you must make a replacement strip, postpone gluing up the rod until everything has a chance to come to equilibrium.  (Robert Kope)

Here's another one. I just put the last coat of varnish on a rod and, as usual, it hung in the cabinet with a light on overnight. The next day when I got home from work I inspected the varnish for lumps and bumps and the  butt section had a major curve in it. This section came out of the string almost dead straight and needed just a minor touch up to straighten and had stayed that way thru the wrapping and first coats of varnish. I waited a few days for the varnish to harden and took it back out to the shop and straightened it over the heat gun on low and it's been fine since, cast it several times, etc. Someone please explain why a section that never had a curve  developed one while hanging in a  warm box. Personally, I think it's evil spirits, but that's just because science and rational thought fail me in this instance.  (John Channer)