Bamboo Tips - Tips Area
Heat Treating - Post-Tapering

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Do any of you heat treat after final planing?  I have noticed (testing, testing, *G*) that I have virtually no lifted nodes if I plane before heat treating. Same blade angle, sharpening, and so on, but no lifting if I plane out first.

If I heat treat prior to final planing, I occasionally get a node gouge.  And yes, I realize it could just be me, but I am curious if anyone else has noticed this.  (Dewey Hildebrand)

I have not heat treated after final planing but I do heat treat after a preliminary taper is started. The rough planing is done after the strips are soaked for five days or so., When the beveling is done to where a 60 degree bevel is beveled on the strip, it goes right to the finish forms and a taper is started while wet. Just enough is taken off so a definite taper is seen. There is no node lifting at all. From there the strips are dried, heat treated, and the final taper is planed.  If you don't plane "Wet" give it a try. Makes nodes real easy to deal with.  (Tony Spezio)

I usually heat treat after final planing. I have noticed the tendency for the node to be more prone to lifting also. Strangely, it doesn't seem to be a problem with flamed cane. I suspect if you wait a couple weeks for the cane to reabsorb a bit of moisture, the problem would go away. I think the problem is that oven baked cane is just too dry to plane well.  (Tom Smithwick)

I watched a clip of Jeff Wagner giving a presentation on planing bamboo and in it he mentioned he heat treats after final planing is complete and not before.  He went on to say that he brings the oven temperature to 375 degrees, puts the tapered strips in, and turns it off and allows it to cool to room temperature before removing the sections.  Anyone else doing this?  (Jim Brandt)

Jeff gave me that advice four or five years ago and I’ve been doing it ever since.  The only time my tempering has ever gotten me in trouble is when I lost faith and wanted to keep the oven (hot air gun) going “a little bit longer,” just “to be sure.”  I’ve since acquired a wonderful oven from Tony Larson (Rush River Rods) which will hold a pretty uniform temperature from one end to the other, but I still plan to use it the same way.

Jeff claims there’s no cane shrinkage (and I haven’t seen any yet, either), plus the untempered cane planes more easily (which I also agree with).  I could only get my heat gun oven up to about 360 degrees,  but you can take it as read: heat, insert, walk away.  Jeff also notes that he glues up the next day, giving the cane time to dehumidify (I suppose).

I suppose the only thing I’m giving up is the opportunity to have the sweeps straighten out by tempering them in an extrusion like Harry Boyd’s, but I could probably get around that, too.  I loosely bind the section together by hand with wide wraps using Jeff’s method, rather than run them thru the binder.  I suppose I could “shim” the finish-planed sections  if I were using Harry’s extrusion.

“Try it; you’ll like it!!”  (Steve Weiss)

No Steve, what you are giving up is the knowledge that your strips are evenly tempered. It probably doesn't matter but this is one of those convenience things that leave you with a variable. The assumption is that a .028 strip heats at the same rate as a .200 butt. Maybe Jeff had hot spots in his oven and didn't trust it. It really doesn't matter, but anyone new on the list should think about this kind of advise and the science behind it before you implement it.  (Jerry Foster)

Obviously, as usual, there's more than one way to skin a cat.  (Neil Savage)

I have done this a couple of times and it worked fine. I use a heat gun oven and I bind the strips as they would be glued up. I maintain a temperature of about 320 F for 30 min.  It takes about 20 min for my oven to get to 320 and I put the strips in from the beginning. I expect that by the time the oven gets to 320 the sticks are pretty well equilibrated. I haven't seen much shrinkage. I always leave about 3 or 4 thousandths for final scraping and sanding. One thing to watch is that the strips will be extra dry and if your glue requires a bit of moisture in the cane It's good to wait a few days for the strips to equilibrate.  (Doug Easton)

This past Roscoe Gathering, Tim Abbott did a presentation heat treating.  One of the methods he spoke about was low temperature heat treating. Specifically, 24 - 48 HOURS @ 250F.  Several folks in the room also said they were doing the same.

The idea being that you are avoiding much of the damage that is associated with heat treating at higher temps.  Bob Milward has devotes a good section of his book to cane damage due to high temp heat treating.  His book: "Bamboo - Fact, Fiction and Flyrods"

Just curious if any list members are doing a similar low temp heat treat.  (Mike Biondo)

I understand nothing about heat treating so I guess my input is as valid as anyone’s.

I think Dr. Schott said something about 340 being a good temp to cause polymerization without harming the cane.

I asked Milward at Corbett Lake about harming the cane and he admitted that he only did extreme tests, like almost blackening the entire strip, well duh.

About Mr. Abbott.. You must see his entire process. He steams his nodes. I tried this also. It will straighten and press nodes, but when tempered to 365 I found that everything popped back. So perhaps his low temp treatment is to avoid this. 250 is barely enough to drive out water. I have never been convinced at what temp the cane is really tempered, but I would doubt if that is enough heat. I am probably totally wrong about that. I wish someone would do some REAL science to tell us the truth, preferably someone without an agenda. Remember that a super dried stick will feel and act like a truly tempered one for about a year.

The way I have found to make steaming nodes work is to pre-temper the entire culm in a powder coating oven, then there is no bundling and heat treating after the fact. Or you can heat it in a cut to length culm in your oven if it is long enough. You can also temper the sticks before doing the nodes, and then soak them and then use a heat gun and press the nodes in a standard fashion.

How many cats is that?  (Jerry Foster)

Well here's what I do and have done as long as I have been building. Perhaps I should say that this is what I have always had as a goal. 350 degrees for 15 minutes. The reason I say that this has been my goal is that I fought with ovens for a long time, every kind of oven you can think of. Finally I ended up back at the beginning and made a new heat gun oven, fought this one to get an even temp and finally nailed it. This oven keeps the temp even from end to end. So what I do is heat and flatten the nodes, bevel the strips and while I am binding them up in the position that they will go on the finished rod I start the heat gun to pre heat the oven. One thing I want to say is that all strips are the same size both butts and tips. I run them through my Garrison style binder and when the oven is at 350 degrees. I place the strips in the oven and time the heating with a stopwatch for 15 minutes. then take them out. the change in color is just noticeable, that is what I want. I figure that by the time I finish planing them they have taken in some moisture, just enough. This has worked for me for many years and like they say if it's not broken don't fix it! That's one way to skin a cat.  (Joe Arguello)

Ron Kusse is one of the top rodmakers in the country, he does exactly that only he uses an iron pipe and a torch for an oven, he stops heating the pipe when steam stops coming out the hole in the end caps. If Ron doesn't know what he's doing after over 50 years of rodmaking and a long stint at Leonard, then we should all quit. I use a mill to bevel and taper my strips down to 40 or 50 thousandths over final dimension and I have been heat treating the last 30 or so rods after running them thru the tapering mill and I'm happy with the results.  (John Channer)

That's the worst way of arguing a point that I hear on this list. Because Jeff and Ron and Dick do it this way. That just begs some dufuss like me to say.."maybe they don't know what they are doing." Oh Dear! I think the answer is, "That's the way I learned how to do it and it's good enough." To this I add, most of us can make good rods but do any of us really know what we are doing when it comes to tempering?

No one who uses this method on the list has ever answered the question of how a tapered strip gets evenly tempered. There must be some logic in there somewhere.  (Jerry Foster)

I think your skepticism/questioning of this heating method is "the" question. Particularly if the tips or over treated. Do the tips come out of the oven darker, which would be a visible indication of a problem. I am curious though. I would have to change some of my procedure to do it but I am curious. (Timothy Troester)

Simply because we don't have this spec'd out to the molecular level doesn't mean a method isn't valid.  Certainly you'd have to concede that if there were serious flaws in an approach, they'd likely have surfaced at some point in the last 100 years or so, nein?  And, in your own words, given that  " . . . most  of  us  can  make  good rods . . .," apparently on some level, we know enough of what we're doing.

Everyone's entitled to pursue what makes them happy, and if the science of this is what turns your crank, lay on, MacDuff!  Do some controlled trials and let us know what you find.

I would, however, request that any of us do this in a respectful way.  I know I'll appreciate that, and I believe there are others who will, also. Thanks.  (Steve Yasgur)

I am thinking there is more than one reason to heat treat this way. Would you share some of your reasoning with us and tell us some observations. For instance, how does this change the milling and/or planing? I am truly curious. Do you think the mass of the oven would influence your result, not only the cool down but also how the heat penetrates the splines? Do you bind your strips or lay them in the oven singularly? (Timothy Troester)

I've been on the list for about ten years and this discussion comes up from time to time! It usually starts out pretty good till someone gets sand thrown in the hair or gets hit by a toy truck! LOL!! Seems to me, it doesn't really matter how, how long, or at what temperature we do it, just as long as we do, do it!!  (David Dziadosz)

I doubt if anyone is really very interested in my, or anyone else's, methods. For what it's worth, I bind my strips with the binder, they just happen to be already tapered somewhat close to final dimensions. I flame all my cane, just because I have some crazy idea that it seems to make a better rod is some indefinable way and I like the color, but I make a few test sections to see if the tips looked like they were getting overdone and they didn't appear to. I had a lot of trouble with my machine damaging the edges of my strips to the point of making them unsalvageable, even with freshly sharpened or new cutters. Since I've taken to running them thru the machine first and heat treating after I've had just the usual few loose fibers that can easily be planed past. I could probably get rid of the strings entirely if I quit flaming, but I can live with what I get now. Just to clarify my viewpoint, I don't give a rat's ass about the science involved, if I was into science I would make graphite rods. All I am really  interested in is what works, that means what has worked repeatedly either for myself or someone I know, trust and respect. I sometimes get an idea or get one here or from someone else that seems worth trying, so I try it, if I like it I try it again, if I don't, I move on. Not scientific, but it suits my nature, I do this because I like to after all, if I turn it into work I won't want to do it anymore.  (John Channer)

John, I wish you would read my messages.. I don't believe your methods are bad. I don't think throwing around names like Glen, Jeff, or Ron leads to anything other than another conversation about how to do it rather than why we do it. Most makers do things because it's part of a process, the tooling we use dictates part of the process and knowledge contributes the other part.

To those of you who question tempering. My suggestion would be to make a few rods without any heat treatment at all. Come back in one year and we can probably have a conversation about why rods take sets.

Tempering, if it really is that , was just explained by Tom. There have been a lot of scientific articles written about the molecular composition of bamboo. Tempering is not done to drive water out of the cane, that's just one of the side effects of heating it bast boiling. If there is any truth to polymerization (cross linking), then that is the purpose. The point in question by most of us is how hot for how long.

I know a lot of you like to think about what you are doing, some don't. Whether you like it or not there is science behind what we do. I just don't like to see people trapped by the" that's the way I learned it " syndrome. There is a better way to make a rod. I don't know the answers, but I know when something doesn't make sense. What I ask the beginners on the list to do is question any advice they get. Most of the "How To" stuff is fine.. any tool or technique you acquire will help. Tony comes to mind if you want to speak of helpful gadgets.

There are really only two critical issues in making a good rod... Cane selection and how you treat  it ( heat treating, hollowing and node squishing come to mind), and the Taper. Although I may have to extend that to guide placement also. All the rest is cosmetics, taste, and craftsmanship.

Believe me Steve, I have done semi-controlled trials galore. By the way CS can also cause salmonella. Most of the people here make good rods, many of the list-members are trying to make the best rods they can. In order to do that they must address the subtleties of the process. The base level is known to anyone who has an interest. Respect.. I have respect for  everyone who tries to make a rod. My writing doesn't however. I didn't think we were here to achieve mediocrity.

Some of the "flaws" are newly introduced and are not from the ages. Do you know which is which? (Jerry Foster)

Jeff Wagner first thoroughly flames his whole culm. The heating of tapered strips is xtra.  (Bob Nunn)

First I think you know that wasn't a shot at your mentor..

And, just for fun.

Because your wrote it in red, does that mean that the uneven act of flaming, plus the uneven act of tempering tapered strips makes an even temper. This doesn't matter, both build wonderful rods.  (Jerry Foster)

I have done some extensive testing on heat treating bamboo.  I have treated at temperatures from 250F to 375F for times ranging from 10 minutes to three hours.  I have measured the Modulus of Elasticity of the samples before and after heating and then again after the samples have been rehumidified to ambient conditions.  What I have found is this:

IT DOESN'T MATTER WHAT TEMPERATURE YOU USE!  Generally, if you heat at a low temperature for a long time or a high temperature for a short time you will get the same results.  Dr Schott concluded that tempering increases the MOE but it only does so while the bamboo is dry, because it has a higher density.  As the bamboo reabsorbs moisture, the density goes back to where you started and so does the MOE.

The biggest advantage to heat treating is the straightness of the strips when you're done.

As to "set" resistance:  I haven't devised a way to accurately assess the tendency.  This may be more a function of a "bad" piece of bamboo.

The dimensions of your strip WILL change when you heat treat.  The bamboo will shrink ABOUT 4% during heating.  If you plane to dimension immediately after treating then assemble your strips, you're in for a surprise.  The assembled rod will reabsorb moisture and expand anywhere from 0.003 at a tip to 0.012 at a butt.  More or less depending on the Relative Humidity of your environment and the actual dimensions of your rod.  And it takes about a week for the strips to re-stabilize to your environment.  (Al Baldauski)

Your tests are correct. I have also run tests on bamboo before and after planing. You are correct in all accounts. The only difference I find is shrinkage is 3% here in the Uk.

That brings me to another point can you really tempering bamboo are are you just really drying it out.?  (Gary Nicholson)

For anyone that may not be familiar with Dr. Wolfram Schott's heat treating research, you can download "Bamboo in the Laboratory" from the Power Fibers web site (here).

If you're not interested in all the details, skip to page 20 to read his conclusions.  But there's a be learned from the details if you'll take the time to read the entire document.  (David Bolin)

I'm with Al on this one. I also years ago did some testing. I couldn't really tell if heat treatment did much of anything. Does shrink the cane for a day or 2 though.

But I still heat treat - much like I place a stocking near the chimney @ Xmas. Santa might really exist and heat treating might really do "something".  (Don Anderson)

John Long says, and I quote "If you flame, you don't have to heat treat."  I once made 2 flamed rods from the same culm, same taper (as best I could) etc.  Same everything except one heat treated after rough beveling, the other not.  No detectable difference in casting, neither took a set... I'm not sure what that proves, if anything because it's a very small sample, but FWIW.  (Neil Savage)

AJ Thramer said the same thing (quoted in print-Oregon Bamboo-no less). Considering that AJ has made more rods than any "single" rodmaker in the history of bamboo rods, I think he knows what he's talking about. I'm sure there are those who would disagree, but the sheer volume of rods that Mr. Thramer has made speaks for itself.  (Will Price)

OK, So here is a newbie question, concern, and confession of being confused.  When I first got into this craft two years ago the one area that really led to doubts was this "heat treating" process.   I did quite a bit of reading of Power Fibers, Bamboo Rodmaking tips, and threads on this list, as well as talks with Tony, Harry (about the fixtures I bought from him) and others.  What I thought I understood was that the main purpose of heat treating is to achieve molecular bonding which cannot happen at low temperatures.  So here we go again with so many theories about low heat for long periods to high heat (350-375 degrees), and now I am once again confused.  Some talk about heat treating being about forcing moisture from the cane, others talk about changing the molecular structure of the cane, and still others claim heating of any method is unnecessary.  There is no wonder us newbies are often confused about heat treating.  Oh well, I guess I'll just carry on.  (Tom Key)

Are your rods fishable? Do they feel right in your hands? Are they weak or too stiff or do they feel like there is a smooth transition as the rod flexes. If all this is okay with you, you’re probably doing it “right”, whatever the hell “right” is….  (Ren Monllor)

Ever have that gut feeling about a blank?  Well, I have it.  Don't feel like the blank I am working on took its intial heat treating well.  As I was planing the strips I had this nagging feeling that I was planing bamboo that just wasn't heat treated properly.

So now that I have completed the final planing I want to heat treat the strips again.  I have them bound and am ready to re-heat.  Question:  Since the strips are final planed, what temperature and for how long do I want to heat treat?  Or is this one for the trash bin?  If it is possible to re-temper I don't want to smoke the tips.

I use Titebond II extend so treating after the blank is glued up isn't an option.  Also use a heat gun oven that can and will go over 300 degrees F.  (Pete Emmel)

Not trying to be disrespectful, but you did test bend the strips before planing? And you're not dealing with a soft culm? Are your numbers spot on? I don't see why you couldn't reheat-treat. For sure shorten the time for the tip sections!  (David Dziadosz)