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 oldschoolcane |
Design and plans for an air flow oven |
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Posts: 63 11/19/2008 18:29 |
I've got most of my equipment together to build rods with, however I am missing a heat treating oven. I'd like to put together an air flow oven that
uses a heat gun.......does anyone have any thoughts or ideas for plans? I looked at the plans on the planing form, plans by Joe McAnulty but there isn't
any pictures to go along with it. I'd like to build a basic heat treating oven but I just need a simple design along with the plans to follow.
Thanks, Tim |
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cross creek one |
#1 | |||
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Posts: 338 11/19/2008 19:26 |
I went to Home Depot and cobbled together various pieces of vent ducting and plumbing valves, with the main body being a five foot long section of double-wall
gas water heater vent. I used two outdoor grill thermometers (screw in probes), some sheet metal screws, and a bunch of stainless steel tape, as well as
chimney-
 insulation (to keep me from burning the house down). A budget heat gun powers the oven. Tips: Your oven won't attain high enough temps unless
the air is allowed to flow through almost unimpeded--in other words, the 3/4 inch brass gate valve at the far end is closed down to lower the temp and opened
to raise it; Even pretty thick pvc plumbing melts easily, and pvc cement even easier--use metal fittings as much as possible and definitely near the heat
gun; The tubing connecting the heat gun to the oven needs to be snug--this was the hardest part--getting parts that matched up from among the available stuff
at H.D.; If you have a heating/AC savvy friend and/or sheet metal fabricator, this whole project will be a lot easier! -CC
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raywright.thebamboorodroom |
GE bamboo oven | #2 | ||
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Posts: 4 11/19/2008 21:22 |
I know that you are wanting a heatgun oven, but if you have 220 volts and a high ceiling I suggest you might try what I did, which is to convert a castoff
kitchen range to a bamboo oven. Basically, I took a kitchen range, removed the stovetop burners and cut a round hole in the stovetop and into the oven
compartment. Into this I inserted and secured a 5 foot section of double wall gas vent
, to a level just above the lower oven rack. I insulated the
exposed portion of the and made provision for two thermometers (one at the lower end, one at the upper end). I can suspend 3 sections in the ,
already have an element and a thermostat, and made the whole thing for about $35. I consider it an airflow oven because, well, hot air rises. Ray
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cross creek one |
#3 | |||
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Posts: 340 11/19/2008 22:21 |
Ray's design might work suspended over a gas or charcoal grill, also. Wish I had someplace to rig that up--I hate the noise of the heat gun. -CC
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Lee Koch |
#4 | |||
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Posts: 408 11/20/2008 00:17 |
I don't have drawn plans for for the Neumann heat gun oven I made, but this description may get you there. Home improvement stores sell flat ductwork that
can be rolled into tubes. Some of it come in 2-foot sections. Buy 3 sections of 6-inch ductwork, and 2 sections of 3-inch ductwork. Buy 2 caps for the
6-inch ducts, and one 3-inch elbow. Also find and buy an electrical tester that has a temperature sensor.
Cut one of the 6-inch sections down so it is only 1-foot long instead of 2 feet. Roll up all 3 of the 6-inch sections and assemble them into a 5-foot tube. Roll up the 2 3-inch sections and assemble them into one tube 4 feet long. Slide the 3-inch tube down into the top of the 5-foot-long 6-inch section. leave about one inch sticking up above the top of the 6-inch section. Rivet the 3-inch section into place inside the 6-inch tube. Place one rivet per section and then the thing won't fall apart. On the top of the 6-inch tube, where the 3-inch tube is sticking up one inch, prepare the 6-inch cap to fit over it. Cut a 3-inch hole out of the cap, so that the 3-inch tube can stick up through it. Cut another hole in the cap the same diameter as the nozzle of your heat gun. Install the cap, down over the 3-inch tube, and fitting down on the top of the 6-inch tube. Go down to the bottom of the 6-inch tube and install the other cap. Note that the 3-inch tube that is inside it will not reach all the way down to that cap. That's OK. Rivet the bottom cap in place. Now, stand the 6-inch tube up. Shove the nozzle of your heat gun down into the hole in the top cap you made for it. Turn it on. it will force air down through the 6-inch tube, then the air will turn and come back up through the 3-inch tube, exiting out the top. Turn the gun off. Drill a small hole through the wall of the 6-inch tube, and also through the 3-inch tube. Insert your temperature probe through that hole and turn on the tester. Ok, you will hang your rod sections down inside the 3-inch tube. Suspend then with loops hung over a pencil or section of bamboo. The 3-inch elbow should be then placed over them so as to direct exhaust hot air way from the heat gun, so that you do not burn up your gun when you run the oven. Shove the nozzle of the gun into the hole in the cap, turn it on, and watch your temperature gauge until it gets where you want. Dial down the heat gun to maintain a steady temp. Cook for however long, then turn off the gun, let cool, and remove the bamboo sections from the top of the oven. Clear as mud, or better, I hope? 
All the best, lee |
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 tylerlane |
#5 | |||
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Posts: 14 11/20/2008 00:26 |
Have you seen this?
http://www.fneunemann.com/fpwot/index.php?id=33 I went to Home Depot and made something as close to this as I could with what they had for sale. The main diference is I could only find 6" ducting, so I needed to insulate to get the temps up where I wanted. Insulated I can get a little TOO hot now. |
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oldschoolcane |
heat gun oven | #6 | ||
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Posts: 65 11/20/2008 11:46 |
This is exactly what I needed, thank you all for getting me started on this tool. Is their much difference in heat guns? I am considering one of the Sears
models, about $100. Any thoughts?
Tim |
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BigTJ |
#7 | |||
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Posts: 567 11/20/2008 14:33 |
I was going to build a nuneman-style heat-gun oven, until I put my digital thermometer in a friend's oven and mesured a temperature delta of almost 50
degrees from top to bottom! They probably work fine, but I wanted soemthing that provides a more even heating along the strip, that was simple to make, and
didn't cost a lot in time or money. So,I just use the old standby steel pipe method. All you need is a 2-3" dia steel pipe about 5 ft long with two
endcaps, some wire to hang it off of somewhere conventient outside, a couple dial thermometers in each end, and a propane torch. The pipe has a lot of heat
capacity so once you get it up to temperature it stays there and doesn't vary much. I just toss the sections in there and rotate the pipe every minute or
so, I don't even use a rack inside of it. It is pretty easy to maintain a temperature range of about 15 degrees, without a major drop in temp when the
strips go in, because of the pipe's thermal properties.
The only drawback is you have to be careful you don't burn yourself, the worst would be to bonk your head on the pipe while it is hot. The major advantage is you don't have to fiddle-fart around with anything really, you can go to the hardware store, get the stuff you need, come back home and in a half hour your are baking your strips. The other advantage is your temperature delta is small, and when you are done you can just stick the pipe on a shelf or in the corner of the garage. I think Per Brandin uses this method and he makes some really great rods. Good luck. |
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gmreeves |
#8 | |||
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Posts: 64 11/20/2008 17:35 |
BigTJ,
Last Edited By: gmreeves 11/20/2008 18:07.
Edited 1 time.
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tylerlane |
#9 | |||
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Posts: 15 11/20/2008 17:50 |
Insulating my Neunemann-style oven perhaps made a difference, but I got a temperature differential of only 15-20 degrees from one end of my oven to the other.
As it approached maximum temperature (about 450 for my oven) that differential was even lower.
For a heat gun, I use a Milwaukee (manufactured by Wagner) that I have had for several years. It can still be had at Home Depot for about $25, and has been plenty sufficient for the one rod I've made so far. (I've used it for lots of other things over the years before rod making.) Since my oven is getting so hot with the insulation, it would be handy to have a variable temp gun I suppose (this one has only high and low heat), but if you just want heat, I don't think you need to spend $100. |
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canerodscom |
#10 | |||
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Posts: 1868 11/20/2008 20:43 Bamboo preacher |
I'm not sure what the problem might be that causes a 50 degree difference in temperatures between each end, but my heat gun oven stays within 6-10 degrees
from one end to the other. I use a $35 Black and Decker variable temp heat gun from either Home Depot or Lowes. You can see some pictures of the oven in the
last few pictures here:
Shop pics Harry
Harry Boyd
maker@canerods.com http://www.canerods.com |
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tylerlane |
#11 | |||
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Posts: 16 11/21/2008 00:10 |
I've only used my oven once, and my memory is fuzzy, but I think that like Harry's my oven settled out to about a 10 degree differential once fully
heated.
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gmreeves |
#12 | |||
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Posts: 65 11/21/2008 12:03 |
I use the same heat gun as Harry and like it a lot. It was very affordable when I bought it. I can't find it anymore at my local Home Depot or Lowes. I
can't remember which one I bought it at but I would like another one.
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oldschoolcane |
heat gun oven | #13 | ||
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Posts: 67 11/21/2008 12:33 |
Well I still haven't made it to the hardware store so this is still a work in progress! I consulted one of the books I've been using in getting my
tools together, "Fundamentals of Building a Bamboo Flyrod", the author actually recommends a variation of the steel
for heating the strips.
George Maurer, suggests using a 6" duct with a heat gun in one end and a open end in the other. I'll look through this description again when I
am not at work and leave a more detailed description of this method for anyone reading about this topic. I'll probably be working on my oven over
Thanksgiving now, its archery deer season here in Kansas and I am busy with that for now.
Tim
Last Edited By: oldschoolcane 11/21/2008 12:35.
Edited 1 time.
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thegubster |
Thanks!! | #14 | ||
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Posts: 1449 11/21/2008 13:24 |
Thanks Tim, I'll be watching this. I'm in the market for an oven at some point. No hurry but I'm looking.
Jeremy. |
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BigTJ |
#15 | |||
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Posts: 568 11/21/2008 17:10 |
The heating process is to just sweep the torch evenly back and forth. Once the pipe gets up to 350 it only takes a few sweeps now and then to keep it hot,
maybe 2-3 sweeps every 3 minutes. The pipe really hangs on to the heat, and you can anticipate what is going on after playing with it for a few minutes, so
it's really very easy. Nothing scientific at all. I don't think it matters if the caps are tight or loose, the steam can escape around the hole you
need for the thermometer. Loose is probably better though, makes it easier to pull a hot cap off and get your strips out when they come out.
The nuneman style oven design isn't insulated, as I've seen his plans anyway, and that's the type of oven I was commenting on. A degree or two difference sees remarkable to me for a nuneman oven, with limited or no insulation. I belive that Nuneman commented on the temperature delta and recommended a flip of the strps. My friend who's nuneman oven I borrowed said he thought his temperature delta was about 5 degrees. It wasn't until I used a digital thermometer with a 48" probe that we found out differently after waiting close to an hour an seeing the equilibrated temperatures at each end. I think the big problem was the base of his oven sits on the floor, which can be very cold in the wintertime, which is when I tested it. Any kind of insulation would probably help, although his oven had about 1/2 inch of foil bcked insulation on it. Maybe adding several inches of insulation is what's helping you guys get the delta down to 10 degrees. Whatever the reason, putting heat on just one end of the pipe is in my mind is the main drawback for that style of oven. Not a fatal flaw just a drawback. A heated pipe is simpler, less expensive and time consuming to make, and steel hangs onto the heat and distributes it much more evenly than aluminum. They both work fine they're just different choices. By the way Harry I like what you did mounting the oven horizontally and using what seems to be insulation. Those seem to be some pretty good improvements over the original design. If I were doing a Nuneman type oven, I would also consider trying to put a heat gun at each end and a vent in the center to keep the heat distribution more even.
Last Edited By: BigTJ 11/21/2008 17:23.
Edited 4 times.
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thegubster |
NICE!! | #16 | ||
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Posts: 1450 11/21/2008 20:44 |
canerodscom wrote: Harry, Nice to see how you've done up your shop. Looks like you've got yourself well organized and all the thought/planning for you has paid off nicely. I like it!! Jeremy. |
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canerodscom |
#17 | |||
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Posts: 1871 11/21/2008 21:51 Bamboo preacher |
Thanks Jeremy,
It does look that way. But some things will have to be moved. For instance, the oven opening is too close to the far wall to allow long strips to go in. Not a problem when the oven is cold, but a major headache with a hot oven. 
Harry
Harry Boyd
maker@canerods.com http://www.canerods.com |
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agedsage |
#18 | |||
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Posts: 17 11/25/2008 14:29 |
Tim:
Excellent step-by-step instructions, complete with a self-explanatory labeled drawing, by Jon McAnulty for his hot air drier can be found at: canerod.com/rodmakers/tips/jmHotairOven.html. Rather than build the large plywood box to put it in and fill with insulation, I would consider putting heating/cooling system air duct insulation around it and attach with the same binders that builders use on A/C duct work. Good Luck, Frank |
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