I recently overdid the heat treating on some cane. I build nodeless and heat-treat in the kitchen oven.  A couple of sections of culm stayed in a bit too long and went to a chocolate brown color instead of the usual honey, some of the enamel bubbled slightly.  They were brownest next to the enamel and pretty well through the wall of the cane.  They still seemed to flex OK so I went ahead will milling them on my Morgan Mill.  Shaving came off the strips as usual.  As I worked I noted that in the dark areas some fibers along the edge were coming loose from the rest of the strip, yet they still seemed to flex OK.  I pinch one of the strips hard between my fingers and rolled it and the matrix holding the power fibers together disintegrated leaving just the fibers connected to normal cane at each end (they had been burnt only in the middle of a strip where they had been over the oven element).  It looked a bit like two paintbrushes joined at the bristles.  I broke a couple of strips in the dark and in the normally colored sections and both left long fibers.  It was an interesting demonstration of what happens to cane when it is heat-treated to too great an extent.  (Bill Lamberson)

I too just cooked some cane to its darkest form. The thing about this was the cane was about 5+ years aged, and I used the same temps & time as with my newer cane. Has anyone found that aged cane generally cooks faster than non-aged cane?  (Chad Wigham)

What I have experienced is if cane is real dry it will darken faster than cane that has been exposed to moisture.  As I soak my strips now I go through a drying regime before the strips are heat treated and come out with strips that look the same from one batch to the next.  (Tony Spezio)

Would you care to elaborate on your technique for those of us who want to do the same as you. (Larry Puckett)

I soak my strips for five to six days. Displace the nodes, do some straightening.

The sweeps can be taken out without heat. Bevel the 60 degrees and from there partial taper all strips. The strips are drying out on the outside but still wet inside. The strips are then wrapped in MD's fixtures with the pith side out.  Not a commercial but this is one of the best things in rodmaking to come along. I made two brackets to hold the three fixtures together, each fixture holds six strips. The whole assembly is put in the oven that is preheated to 100-120* F. The door on the oven is left cracked open at the top. The strips are left in the oven for a hour or two then I check for moisture with a mirror.

If moisture is still coming out of the top of the oven, the mirror will fog up. When the mirror does not fog up any more I assume the strips are dry enough to heat treat. The assembly is removed from the oven and cooled. The strips are now rewrapped with the enamel side up and heat treated. I did not mention the strips are about as straight as you can get them. The strips are then heat treated for 12 minuets @ 375 F, removed from the fixtures and final planed. I try to do heat treating, final planing and gluing in one session before the strips can absorb any moisture.  After the glue is set for 18 to 20 hours, the sticks are scraped, sanded and heat set using the fixtures again. After heat set for four hours the sticks are removed and while still warm given a coat of Tung Varnish to seal them.

All the final sanding and additional coats are done when each coat is dry enough to sand.  (Tony Spezio)

It seems reasonable that it might.  Boiling the moisture in the cane is going to absorb heat until it is largely removed.  Once the moisture and perhaps other volatiles are gone I would expect the temperature to rise and other chemical changes, the caramelization process, to occur.  The color change takes place pretty quickly once it starts.  If the cane is dry to begin with, the drying phase of the process would be likely to occur more quickly and the chemical changes to begin earlier in the process, so if left the same amount of time it would overcook.

There is good logic to using a regimen consisting of a long period of a low temperature (say 200 degrees) drying phase, followed by a higher temperature (say 375 degrees) tempering (for lack of a better word) phase.  The drying phase would equalize the dryness of all cane whether "green" or relatively dry, and then the higher temperature would take care of the subsequent chemical changes.  I know that some do it this way, and I will probably join them.  (Bill Lamberson)

I believe that's pretty much what's happening in the drying/heat treating regime that M-D and I use in our convection ovens.  He can probably expound more on it than I can, since he developed it through experimentation.  We put the strips, bundled onto the fixtures he designed, into the cold oven.  Then we use a set point of 350 degrees, and let the oven come up to the temperature with the strips inside, hold it for thirty minutes at 350, the adjust the set point down to 225, and hold that for an hour.  I think the 225 point just removes any residual moisture that may have been trapped in the strips.  Using the oven this way, I have gotten a pretty uniform golden honey brown color on all  my  strips  so far.   I probably  wouldn't attempt  this in a non-convection, non-PID controlled oven, since the heating may not be as uniform throughout the oven.  I've laid the strips from the current rod I'm working on alongside two previous rods, and the coloration is so close the difference is virtually undetectable.  (Mark Wendt)

I agree with Mark completely that this regimen should not be attempted without benefit of both a convection oven and a PID process controller. I think you'd find some very crispy strips indeed, otherwise.  (Martin-Darrell)

You are right, I tried to dry and heat treat at the same time and got some dark brown strips. I set the oven for 375 F put the assembly with wet strips in and let it come up to temp. When it got to 375 F I timed my 12 minutes. The strips were overcooked.  (Tony Spezio)

Is there noticeable change between the end of the 350 degree phase and the end of the 225 degree phase?  I would argue (without much conviction since I don't have any data) that the 225 degree phase should be first, then 350.  I would expect much moisture to be left after a half hour at 350.  Have you weighed a strip before and after the 225 phase?  (Bill Lamberson)

I don't know for certain, since the strips don't leave the oven during the cool down phase to 225.  I haven't weighed a strip, since I don't have a scale accurate enough for such light weights.  M-D, could you weigh in (pun intended...) on the reasoning of the process?  (Mark Wendt)

By putting the strips into the oven upon initial startup, the strips and fixtures all acclimate at the same rate, at the same temperature. The reasoning behind this was that the strips and the moisture they contained would all heat evenly, helping to evacuate the moisture more evenly and easily. It takes approximately 40 minutes for my oven to come to temperature so this allows time for moisture to escape. I have noticed however that no steam is present, coming from the strips, until the oven reaches around 300°, and that none is escaping at 225°, though one may feel the increased humidity level inside the oven at temperatures between 225° and 325°. Above that the heat is too great to sustain the moisture level, and it must escape the oven. The total time in my oven for the entire regimen, as outlined by Mark in a previous post, is 2 hr., 10 min. It takes approx. 40 minutes for my oven to reach 350°, from the ambient temperature, so this allows ample time for the moisture to come to heat and begin to move. I suppose that in this respect the 225° phase does come first, but to answer Bill's question, I don’t know, as I never removed a strip just to weigh it at that point.  (Martin-Darrell)

How does a beginner know if the cane has been over cooked? What properties can I look for.  (Scott Wolfe)

Color tells you a lot regarding the cooked state of the cane. Milward demonstrated that a color change to the cane was detrimental to it, however I wonder just how critical this is to a trout rod, as it seems there's very little that we do to the bamboo in the heat-treating/flaming process that results in catastrophic rod failure. Now, for larger rods I do not flame, and I'm careful to give the best heat treatment I can without compromising the bamboo, or at least what I assume is not compromising it based upon what little testing I do to each strip after it's been cooked. The finished rods also seem to bear this out.

Bob Nunley once told of cooking strips to the point of deep brown, yet made a rod from it anyway just to see what would happen. At last report, the rod was still doing fine.  (Martin-Darrell)

What is a PID controlled oven and is it possible to convert my Cattanach oven to this and what would it cost me? Is there some one I can get to do this or are there ovens for sale that are already PID controlled?  (Patrick Coffey)

A PID (Proportional-Integral-Derivative - phew!!!) controller is a high falutin' thermostat that uses fuzzy logic to stabilize temperature.  With the right setup (insulation, air flow, etc.), and the appropriate PID controller, you can keep the temps inside the oven ± 1 degree.  Not sure how much improvement you would see in a non-convection oven versus a convection oven, but at least the temperature near where the thermocouple would be located would stay within that 1 degree variance.  The beauty of the convection ovens is that the moving air mass inside the oven is constantly moving from the side where the elements are to the other side where the cane is cooking, so the air mass tend to have a somewhat stable temperature throughout the oven,  since the air mass is constantly moving past the thermocouple, the PID controller and it's associated thermocouple are sensitive enough, and have the computer logic built in to it to be able to adjust fractions of a degree temperature wise the overall oven temp to hold it within the tolerances.  The first time you fire up the oven, you set the PID controller to auto-tune itself to the set point, and then it determines how many times per period of time it has to activate the relay to turn on current to the heating elements.  After that, you just let the computer do it's work.  I can even open the oven door, and leave it open, and not notice more than 1 degree of variance.  In fact, when I'm going through the initial phase of the regimen I posted before, I open the door to let the steam escape between 275 and 300 degrees, and the PID controller will compensate, keeping the temperature climbing to the set point.  The controllers run about $230 for the 1/16 DIN size, which is what M-D and I use.  (Mark Wendt)

What kind of an oven do you have?  I am using a simple electric element in the bottom of a well-designed box, well insulated that can easily keep the temperature as close to 375 degrees. as I want (or lesser temperatures for gluing).  To control temp. I have used two ordinary contact type thermostats installed through the top of the sheet metal oven shell that seem to record temperatures fairly accurately.  (David Parker)

I built a true convection oven, through the help of M-D, and using Don Andersen's basic set of plans.  There are two chambers in my oven, one for the rack that holds the cane and the thermocouple, and the other chamber that holds 2 - 850 watt heating elements, and a 1/4 hp driven (through pulleys) fan that's enshrouded by a 6" diameter duct.  The fan blows down one side, over the heating elements, around a radiused piece of sheet metal, through the cane cooking side, back around through the fan side.  Each corner of the box has the radiused piece of sheet metal to smoothly direct the air around the box.  You can see pictures of the oven throughout it's construction phases here.  The beauty of convection ovens is there will be no hot or cool spots anywhere in the oven, due the circulating air mass, something that's darned near impossible to achieve with a non-convection oven.  (Mark Wendt)

I've gotten more consistent heat in my Cattanach style ever since I put in a steel plate between the heating elements and the wire rack (thanks to whoever suggested it on the list). The 1/4" thick steel plate (which only cost me about $9) fits tight in my oven (width and length wise), absorbs the heat and helps distribute it more evenly throughout the oven (like a brick pizza oven).  I track the temperature at three different spots in my oven and while it isn't exactly the same at all three spots it is a whole lot better than I was getting without the steel plate.   However, I have often thought about adding a fan at the far end of my oven to assist in the movement of the air inside the oven.  (Bob Williams)

Actually, the PID controller is just a nice thing to have, since it will manage the temperature so well.  However, I think most folks would see an improvement in the repeatability and consistency just by using a convection system in their ovens.  It ensures truly even heating throughout.  I could put a thermometer any where in the cane chamber, and the temp would be identical.  The PID controller is just icing on the cake.  Heck, Don Anderson's ovens were built with a stove thermostat, I believe, and he's reported great results.  My PID controller was gotten 'cause I happened to listen to a smooth talking character, who now happens to be one of my best buds. ;^)  (Mark Wendt)

Fellow rodmakers ...lend me your thoughts.  I made yet another newbie mistake, or maybe it would be better described as a STUPID mistake, and I'd like to get some opinions.  I was showing rod #4 (ready for reel seat mounting) to an acquaintance and he asked "How strong can something so delicate be?"  Of course I felt obligated to demonstrate and grabbed the tip section and gave it a healthy flex. Snap!  That was the STUPID mistake.  Now comes the  question - It seems to me that the tip should not have snapped, but even more disturbing is that it did not splitter the way I would have expected, with the bamboo fibers flaring.  Rather it snapped like a piece of  wood - straight across.  Does this indicate I might have overcooked the cane sticks and they became brittle?  (The break did not happen at a node.)  Once the section was broken (it snapped about 12" from the tip), I purposely broke it in several more places to see if the same type of fracture would occur.  Some spots splintered, as I would have expected, but others broke clean across.  (Tom Key)

As you surmise you have a bad piece of cane, or more accurately a bad section of cane rod.

Healthy undamaged bamboo should have long splinters. A clean break means structurally compromised cane.  Overcooking is certainly a possibility. . .though I'm sure there are others.  (Chris Obuchowski)

Ed Berg, among others have done some quantitative test with heat treating cane.  Ed's test was relatively simple but pointed out a the relationship between temperature, time, and cane failure.  Ed builds nodeless rods and treats the pieces prior to gluing.  They cast quite nice, and are exceptionally straight given that they are hand planed, and hand bound, as well as very well finished.

I cannot remember exactly what he found about over heat treating and under heat treating.  (Greg Shockley)

My first thought is that you did this test too soon after the cane was heat treated, and it was still dry and brittle. It takes a couple months after heat treatment for the sections to come into full equilibrium with the atmosphere, and probably a couple more if the rod is varnished. Too much moisture is no good, but that does not imply that "0" is any good, either. Having said that, let me also say that after reading Milward and Schott on this topic, I did back off my own heat treating a bit, where I used to cook to a medium brown, I now go for just the slightest color change, a look that I like anyway. I would also suggest that after you split your strips, that you test bend every internodal area to seek out areas of weakness. If you find a spongy area, reject the strip.  (Tom Smithwick)

It sounds as if you over heated/tempered the cane. How did you heat treat, and by what method and time did you use?   (Bruce Herndon)

I am guessing that you over cooked the cane and it became too brittle in local spots. What was your cooking regime - time and temp; color of the cooked cane; oven temp distribution, etc.. ? Just my thought.  (Frank Paul)

I was not in my office for a while, but I do think I can provide some hands on information here.

I use local cane, and I always test my culms before using them. Sometimes, most culms are OK, sometimes, I have to dump almost all. My cane if cheap, so I don't really care. My test is exactly what you experienced. I take a strip of a culm and break it. If I see lots of spiky stringy fibers parting with difficulty, its a good culm. If it snaps like a dry stick, its a bad culm. There are in betweens naturally, and some go some stay.

I also grill my cane on a BBQ. On the hot coals. It flames and colours in cloudy browns and sometimes almost black. And of course, when I am grilling my cane sometimes, something happens, I leave the cane 'just a second' unattended and it bursts into flames. Then it is really charred and burned. Sometimes it is still OK for a rod, and again my test is a breaking test. When the cane is really black and charred, it still breaks 'stringy'; When totally burned, it just crumbles. So, I don't really know where some people think that overheating it would make a piece of cane break clean as opposed to breaking in fibers. My cane doesn't...

I think you had a bad piece of cane to start with and heat it or BBQ it or use it as it is, it will always snap as a dry stick. Test your culms before you use them...  (Geert Poorteman)

In my question posted yesterday (see above) I failed to tell that the culm was flamed to a nice dark caramel color then heat treated in an industrial oven at 350 for 15 minutes.  I think this is very important information I should have added to help give those of you who are responding a better picture of my cooking process.  Once again, I value your input in the hope I will not waste so much effort on future rods, and have a better end product.  (Tom Key)

You should have only flamed the rod as you described. It sounds like by moving on to the oven for 350 degrees for 15 minutes, the cane was over cooked.

When you did your flaming, did you notice any moisture or resins exiting the cane at each end?  (Bruce Herndon)

I think if you flamed to that extent, you do not require any more heat there after.  (Gary Nicholson)

Not that I have anything new to add but My unscientific findings were exactly as Gary's.

A couple of makers, well known, (expensive rods) have their culms baked in a powder coating oven until they are deep brown all the way through. I tested and used one of these culms and although the pith was almost completely cooked out the bamboo still broke as strings.

I think that Milwards research is valid, but I think there was an agenda in place that caused him to skew his conclusions.

I have a rod that I cooked the cane at 400 deg. for 23 min. I still have it and it works just fine. I won't do it again, but it was a good test. Cooking to those levels certainly does the cane no good, but it does make a stiff rod.

You didn't mentioned how you flamed Tom?

I flame and bake. As a matter of process constancy, if you flame you have an unknown or uneven amount of tempering (if you believe that flaming tempers the cane) so in order to normalize the cane I temper it in an oven to bring it to a reproducible known.

The reproducible rod itself is the result of consistent processes, not one of artistry.

Cane will break clean around the nodes if you heat straighten it. Do I still do it, yes.

I think you had a bad culm. Or it could be the flaming technique.  (Jerry Foster)

You overcooked the stuff. Heat treatment is a cumulative process and you probably gave it enough for 2 rods. Do some test strips and find a heat treatment regimen that works with your equipment without crisping the cane.  (Larry Puckett)

I was going to put it that tersely, but the necessary courage was not in me that night!  I also think that he may have had some slightly duff cane, like we all do from time to time.  (Robin Haywood)

If you've been following the comments made by others regarding my "cracked cane" question, you know there is a range of opinions.  My biggest concern was the straight across break in a couple of spots, so the idea of flexing each strip between nodes after splitting makes good sense.  That being said, I'm also pretty sure I cooked the hell out of the strips in the attempt to make sure they would not take a set - a problem I fought with my first three rods. (That mystery was solved after I had already cooked the strips to "well done.") So far I don't feel too bad about my failures since none of the rods have been sold.  I'm sure I will continue to make mistakes for some time to come, but I hope to reach a state of enlightenment some time soon.  For now I will resharpen my plane iron, pre-flex all the strips, and cut down on my heating routine - I love that caramel color!  I'll let you know how my next attempt turns out.  Thanks to all who were willing to give their opinion on this conundrum.  (Tom Key)

You are right not to feel bad about mistakes. It's the mistakes we make and what we learn from them that makes the learning curve shrink. If you change your process and don't quite get the caramel color you are looking for, I'd recommend purchasing a jar of Jeff Fultz’s cane browntoner. Easy to use and you can go from a light honey color all the way to a rich FE Thomas type browntone. No financial interest of course, I'm just satisfied with the product.  (Will Price)