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Main Boards => The Bowyer's Bench => Topic started by: Dick in Seattle on November 26, 2008, 06:01:00 PM
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I'm very close to done... I have it on and heating right how. I can't see any light under the lid edges, but I think I still need to do some more sealing. I put a bicycle valve in it and pumped it up to check, and there are still some air leaks, but I figure I can caulk those after it's been heated up a few times. That way if there's any warping from the heat, I can adjust for it.
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Your oven is air tight?
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Ah, I love to go fishing... I got a nibble, too :^) All in fun... I was kind of frustrated because I had some problems getting a decent lid fit... not air tight, but good enough.
And seriously... I did finish it this afternoon. not exactly an uncommon project, but I did come up with a wrinkle or two. Here's a link to a set of pix and explanations of what I did and how I did it....
http://www.dickwightman.com/bulletinboard/ovenpix/oven.html
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Good job! Where'd you get that foil insulation? I may just redo mine.
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the insulation was from Lowe's. It comes in rolls, two sizes... one is $20 and 16" wide, the other is $45 and is 48" wide. For the size box I built, it turned out I needed the larger one. Too bad you're not close... I ended up with enough left to do another box, but it's too large to be conveniently shippable. It's great stuff... space developed... my wife used to use it insulating boats, so we had some familiarity with it. I think it's probably commonly available at building supply places now.
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Your oven looks great! I think I may reline mine as well...when the aluminum tares from use.
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Dick, Your box looks like mine. Is the design from Bingham's Projects? I know by making your box air tight, just like a house, you make it more efficient but is that necessary for it's intended use? Mine is fully insulated but by no means air tight. I only use mine to dry wood and maintain low M/C of bow wood for self bows and for curing all wood glue ups. etc. Pat
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Okay... I've had a lot of replies and questions from various sources... here are some answers:
First, sorry guys... the airtight thing was a joke, really... I tried for a good lid fit to avoid heat loss, but I'm not that obsessive :^)
Someone expressed concern about using a thermostat, saying that they had found the one from Binghams to have a much wider range than advertised. As noted on the web page, I haven't wired the thermostat in yet, but I will be testing it before it do. I liked the fact that it is a narrower range than Binghams.
I was asked why not use wheels for movement... I seriously considered that. Everything else in the shop is on wheels. However, in this case, the main movement to be considered was the tilting up. I was also thinking that it may spend time on a table, though now that it's a reality, that may not work... too high. I may give wheels some more thought... at least on the end.
Will this insulation stand the heat? I'm not the first to use this type of insulation in a hot box... it appears to handle the heat. This stuff is building code approved for ceiling and attic use in Dade County, Fla. I've lived in Dade County and they have one of the very best building codes in the US. Believe, me, if you wanted to cook a bow in Dade county in the summer, all you'd have to do is put it in the attic... no oven required! If I run into problems, you'll hear about it.
Also, I should note I got a couple of questions about the wiring. The wiring is carefully channeled behind the insulation on the lid. When I first fired the box up, it went to an internal temperature of 195... hotter than I would want to use, obviously... and the outside of the lid was completely cool to the touch. This insulation may not have been designed for this use, but it has outstanding reflective capability.
I've also been asked about a timer. It's a possibility. I was looking at outdoor Christmas decoration timers at Lowe's yesterday. I'm almost more inclined to not put one in than to do so. This is not an item that should ever be left on if you leave home. My idea of using it is to cook a bow while doing other shop projects... i.e. stay on hand, don't leave it unattended. I spend a lot of time reading and smoking my pipe; I can do that in the garage, too. I'm sure I'll be checking the internal temperature every half hour the first couple of times I use it. Probably ought to also add that the garage has a smoke detector and fire extinguisher.
Hope all this and the web page cover everything for anyone interested.
Dick
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Dick, I did put coasters(a couple of $ at ACE) on one end of my box so I can flip it on end and roll it out of the way. Comes in handy is a smaller shop.
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Dick, the oven looks real good but you were a bit of a worry with the airtight lid...Glenn...
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I've been planning on building my cooking box shortly and I keep coming up with the same question....why not put the heat source in the bottom & build in a ledge above the bulbs that would hold a couple boards for the bow form to sit on? This would allow the lid to be just a flat piece of plywood because everything else would be contained in the bottom.
Crazy idea?
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hmmm.... others know more than I do, but just off the top of my head, it would probably work, but would change the heat dynamics a bit, since the bow would be up in the hotter area... you might need to watch the temp more closely and/or use a lower thermostat. Not sure how much up/down heat variation there would be in a contained area this size
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Exactly Dick...I could use lower wattage bulbs to get the same temps possibly and it wouldn't tip over when I opened the lid!
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Dick .
As far as using a timer I do it all the time. I use a light/appliance timer on my box for an automatic shut off. That way I set it and forget it. As for the accuracy of the Binghams thermostat I wouldn't worry about it. The way that epoxy works does not require a specific exact temperature. The only thing that heat does is speed up the curing time and make the cured epoxy a little less susceptible to heat. In my experience of laying up fiberglass aircraft fuselages A variation in temperature during curing is not going to affect the performance of the epoxy.
One last thought for all to ponder, I was told that in a few years incandescent light bulbs will no longer be available in the US of A! Thank you congress! We will be buying fluorescent light bulbs from China (From what I understand they cannot be made in the US) and if you break one you should bring in a hazardous materials clean up crew. I am starting to toy with the idea of using one of the little quartz heaters as a heat source. Just a little something to think about.
pennsultuckey pete
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"Many of these state efforts became moot when the federal Clean Energy Act of 2007 was signed into law on December 19, 2007. This legislation effectively banned (by January 2014) incandescent bulbs that produce 310 - 2600 lumens of light [7]. Bulbs outside this range (roughly, light bulbs currently less than 40 Watts or more than 150 Watts) are exempt from the ban. Also exempt are several classes of specialty lights, including appliance lamps, "rough service" bulbs, 3-way, colored lamps, and plant lights."
Quote taken from Wikipedia online dictionary
The effective date should give you five years to use and stock up on bulbs. also, notice that bulbs above 150 watts and "rough service" (I use 100 watt in my drop lights) bulbs are exempt.
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I have thought of making a vertical oven like a cabinet,with a heat source at the top and a small fan to circulate the heated air thru a return to the bottom. Am I nuts???
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Mark Baggett(Pappy) has a heat "closet" at his shot that is about 3' square and tall enough to keep staves and bows that are being worked on and to maintain good m/c in finished bows. I believe he uses a small heater with a fan as a heat source.
Pat
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I couldn't get the pictures to come up.
I just used two sheets (4'X8') of 1/2" foil backed foam insulation to make my hot box. I put two each 60 watt and 100 watt bulbs in it and can maintain a temp. of 160* plus. I use a light dimmer switch and a timer on mine. It is light enough that I can just pick it up and move it.
(http://img.photobucket.com/albums/v511/aeronut/DSC00243.jpg)
The light sockets are mounted on paneling scraps and wired with THHN wire.
(http://img.photobucket.com/albums/v511/aeronut/Lightmounts.jpg)
Dennis
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I am thinking of building a foam box. My plywood box lives in my shed and is a pain to get in to the house for a glue up. I wish I had thought of using foam the first time through. How did you mount the light sockets? Is there some type of wood backing or is that gator board?
pete
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The squares in the picture are cut from some scrap paneling. I put a square on both sides of the foam board then just ran some machine screws through to mount the sockets. It insulates the socket from the foil and gives it more strength.
Dennis
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I finally got the pictures to come up Dick. I like the prop for the lid. I set mine close to the wall so the lid rests against it.
Dennis
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I built the Bingham oven and like you, the first thing I noticed was the possibility of it tipping over. Like Dennis, mine is next to a wall but I still went on the inside of the lid and box at each end and added 1" heavy nylon straps that wont let the lid go past vertical. They fold into the box when lid is closed. I folded the ends of the straps so that I could screw through a double layer to attach them. This prevents them from tearing out.
Ronnie
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Dick,
I really looks good and that is one of the many things I will build before starting my bow. One question: Could you have mounted the wood board with the lights after the insulation was put on the lid? This would have eliminated the worry of wiring shorting to the foil on the insulation.
BTW, I like the idea of the wooden slats on the end so the box can be stored standing on end. I'd never thought of that.
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yes, I suppose I could have mounted the light board after insulation, but I had a slight concern re protecting the wood from the light bulb heat. A bow will be in there for as much as six hours. Probably not a problem, but the thought occurred.
Depending on the height of your ceiling, low casters would be even better than my skids. I'm looking for a set that's low enough for me to get away with.
Final comment, if I were doing it again, I'd look really hard at that all foam constructed one like Areonaut's. Maybe not as durable, but probably plenty strong enough with reasonable care, and would be much easier to handle.