Six strips are bound into the fixtures to facilitate heat treating rough planed strips of bamboo. Because the fixtures are rigid, they promote straighter strips right out of the oven. Strips are heated more evenly because the fixtures allow air to circulate around the strips and avoid the propensity of bamboo to insulate itself. Even individual strips can be safely heat treated without the hassle of binding to a wooden dowel.
Fixtures and Ovens
In March of 2006 I acquired the rights to produce and sell M-D heat treating fixtures from Martin-Darrell. The fixtures are star shaped aluminum extrusions 5' long.
To use the fixtures optimally, have any node work already done. Rough out the strips into untapered equilateral triangles via your normal methodology The straighter the strips are going into the fixtures the better the results will be. The fixtures are not a fix-all for crooked strips but are a better method than rod makers have ever had before. They will not, however, straighten nodes.
The fixtures are made for strips .187" and larger from flat to apex. You may cut the strips very slightly smaller than .187", but go too small and the strips will not bind into the grooves of the fixtures. Remember that your strips will shrink during heat treating. If your strips are smaller than .187", you may find that they will not be held firmly by the fixtures after the moisture is removed during heat treating.
Frustration with the un-even heating and expensive yet short-lived elements in the mica strip ovens I have made and used, prompted me to design a simple and affordable oven. One of my fishing pals spent a career in HVAC design and installation. As we discussed my ideas he became fascinated with descriptions of heat gun based ovens. We worked together diligently for several years and through four (now six) iterations before settling on this design. This heat gun based oven holds temperatures within one percent of the set point at any point in the oven. Temperatures from 100*F to 400*F are quickly reached and consistently held.
The picture on the left is one of my ovens in Bob Nunley's shop. R.L. Nunley Fly Rods The oven on the right is the one in my shop and used in making all my rods.
Interior length of the oven is 60 inches allowing it to easily handle strips for two piece rods up to 9 1/2 feet.
The digital thermometer provided to monitor temperatures in the oven.
Cost for the entire setup including oven shell, section rack, thermometer, heat gun holding device (bungie cord), and heat gun is $595.
Packaging and shipping via USPS Priority Mail in the US is an additional $100. Please contact me for pricing on international shipping. I try to keep a few ovens in stock but they are bulky and take up valuable shop space, so please allow me lead time of ten days to two weeks.
Using the Oven
To use the oven:
First, carefully unpack the oven, heat gun, bungie cord and thermometer. Place oven on sawhorses or other suitable structure. The small hole for the heat gun in the open end goes on the bottom. Install the heat gun in the small hole. Sometimes it's a tight fit and might require some wiggling. Once it is in place, secure it with the bungie cord. I like to position the oven so that the dial control for the heat gun is easily visible and accessible.
Install the thermometer probe in the hole at the top-center of the oven. Use a flashlight to peer down the dual walled furnace pipe. The thermometer probe must extend approximately one inch into the round pipe. Fashion a small "stop" for the thermometer probe from tape. I use foil tape, but even simple masking tape will work. As the oven heats and cools, the probe opening grows and shrinks. The "stop" for the probe helps hold it the same distance into the inner pipe.
Choose your heat treating regimen. I use 11-14 minutes at 375* Farenheit, but you may choose your own schedule.
Turn on the thermometer by pressing the on-off button. It should read whatever is the temperature of the room.
Turn the heat gun on at its high fan speed, and the temperature selector to full power. All LED lights should be completely visible. Allow the gun to warm the interior surfaces gradually. (At a shop temperature of 70*, my oven takes about 25 minutes to reach 375*) Watch the thermometer. As the temperatures approach your target, gradually turn the heat gun to a lower temperature by rotating the dial. I find that I need the dial just above the point where all the lights are on at their brightest. By adjusting the dial and waiting a minute or two, you can dial in whatever temperature you choose.
Allow the temperature to equalize from end to end by holding a steady temperature for at least five minutes before inserting bamboo. When the temperatures have been steady for more than five minutes, insert your bamboo strips and begin your heat treating.
Additional hints -- The aluminum heat treating fixtures will absorb quite a bit of heat from the oven. When using the fixtures, I pre-heat the oven to about 400*. When the bound fixtures are inserted in the oven, the temperature drops to a reasonable heat treating level.
To counteract the heat synch affect of the fixtures, in summer, I'll set my bound fixtures outside in the sunshine while the oven heats up. In the winter, I'll gently warm the fixtures themselves over another heat gun, or even lean the bound fixtures against the radiator heater while the oven warms up.
Please call with questions about the oven use, or suggestions on ways to improve the process.
Harry,Well after 12 or so years of cooking cane, finally an oven that works as represented! My compliments to you and your cohort.
The oven arrived this past Friday, in perfect shape I might add, and I put it to work this weekend. It is everything you claimed it to be and more; simple to use with precise controls and consistent results.From one who carelessly burned a lot of cane in what I call a heat smoke stack, MY Thanks to You Both for a GREAT TOOL.
Using it for the first time. Best money I ever spent! Thanks. JV
.....Your comment about your oven holding a steady temp across the length of the oven plus the simplicity of just using a heat gun made it a real easy decision to buy one. Sometimes as rodmakers we tend to over-complicate things when the KISS approach is what we should be following...
Oven as advertized.........Thanks
Harry,I have been delinquent on letting you know that the oven is working perfectly. My shop is heated so the ambient temp is not a problem. Thanks for offering a great tool to the builders out there.
Received the heat gun, etc and had to try it out. Really easy to set and maintain the temp. Where do I leave you a review. Fine piece of equipment.