This displays the plans and will contain construction photos along with FULL details on what was used and how this foam latex oven was built. As you see, this is a fairly large oven. I designed it using GARY BOHAM'S excellent treatise on the subject and worked out how large I wanted it to be for what I would likely use it for. I am making it large enough to comfortably accommodate a cast which can extend from the neck to the knees for a partial body suit if need be. But I am adapting things so I can "block off" part of the oven in case I want to do smaller casts and don't want to have to heat up the entire oven to do that. I have begun the construction phase now, having accumulated most of the supplies I need to do the construction. I still have a couple other items to get but as soon as I do, they will be photographed and added so you will see the finished product soon.
I know most people won't ever want to build one this size, but I am going to include the plans I drew up and the cost list for all the pieces and parts so you can see what it would take to do one this size or something smaller as your needs would dictate. I will attempt to give you alternatives so you can "adapt" these concepts to your own size oven, should you plan to build one. I am not too sure how long it will take to finish the construction but I hope within the next month at the most, this will be done.
Below are the drawings from which I am building this oven. You will see that it's relatively large but not too big. If you have any questions as to what is what, let me know by E-Mail and I'll try to explain in detail. I WILL explain it all in complete detail ultimately as I add more photos to this area. The big scans of the plans are rather large and take up more space than most screens can accommodate, so be sure to allow time for them to load fully. If you have some software to view these you might want to save them and resize them a little smaller to see the whole thing on whatever your screen size is. But I felt the need to keep them as large as this so you could see the detail and the printing on the page. Plus if you wanted to print them off you could do that at this scale.
This is a small scan of the plans I drew up to build this foam latex curing oven. If you look at the larger photo (by clicking on this drawing) you will be able to see it more closely. This drawing was done to scale on an 8 1/2" X 11" piece of paper and at a scale of 1/8th inch to the inch. The larger drawing shows much more detail. Many of the basic items are shown below with more photos to come later.
This is just the side view of the oven as shown above. Just click on this to go to the enlarged photo. You MAY want to save these to your hard drive and print them out on a regular sheet of paper. They might be easier to read that way. But do it from the enlarged shot of these plans.
This is the basis for the whole oven. The "framework" is created out of this 1 1/4" X 1 1/4" slotted steel angle. this material is pretty sturdy plus it gives you the chance to do some adjusting of the construction "on the fly" so to speak. One of the issues I found with this material is that buying them close to the correct or needed sizes is fine. EXCEPT that when assembling the pieces sometimes the holes don't always line up. But with several of the pieces I had to cut the dividing piece out between slots to make it line up with the corresponding piece. But it went together rather smoothly when I got those taken care of. The whole thing was assembled with nuts, bolts and washers.
This is a view of the gussetts, the nuts, bolts and washers used for the construction. The one thing I urge anyone to do, who uses the slotted steel angle, is to be sure to take a short piece with you so you can get the correct size bolts, and the corresponding nuts and washers to fit. I'll give you those in the parts list. The bolts and nuts that I bought, that were supposed to go along with this slotted steel angle, fit the holes fine. They DID NOT fit the slots however. They were too heavy a gauge. And by the time I started this - long after I bought the materials - I felt I just couldn't return them. So I decided to use the washers but had to go to the hardware store and buy a better fitting bolt and nut combination. I bought a box of 100 each and along with the washers that I bought at the same time as I did the slotted steel angle, I had enough to complete the construction of the frame. Check the parts list for these items.
This is some wicked material to work with. If I am in the same room with this stuff, I start to itch. But it MUST be cut to size to "friction" fit into place. Just be sure to use old clothes, gloves, long sleeve shirts or whatever. You might wash the clothes a few times to then get the fiberglas out of the fabric. Anyway, using a standard utility knife you cut the material to size and then fit each piece into the frame of the oven. I will explain how the pieces fit into the whole construction when I show you the photos of that phase. Basically, I build the sides, the floor and ceiling and then finally the back. The front will be a "plug" door that will be cut and fit into place when the main body of the oven is complete. All the pieces are double thick pieces of 1" fiberglas insulation that is foil backed. You will see later how each piece will overlap to help keep the air from escaping from the oven when completed. The uncovered faces (non-foil side) of the insulation will "face" each other and everything will be taped together with high temperature aluminum foil duct tape. The edges of the insulation will be dealt with later so you know how those are treated. Suffice it to say they are sealed with silicone that has been thinned down and saturated onto the edges of the insulation.
RIBBON COIL HEATING ELEMENT
Here is the heart of the operation. Basically this is a high temperature Chromolox open coil assembly, convection type, ribbon coil heater. This is a 2500 Watt heater assembly that can heat up to temperatures of 750 degrees. Now I know we never go that high on anything when running foam latex, but this is capable of that.
Besides, part of the "magic" of building an oven such as this is that you have to determine how much cubic feet of space the interior of the oven takes up and how much heat it takes to run at a controlled, even temperature for the length of time needed to accomplish what we use the oven for. And that isn't easy to figure. You have to determine the cubic feet - how wide, times how high, times how deep. Then you have to determine how many watts of power it takes to run an oven that size. The heater has to be purchased to accommodate that, as well as the other components too. Then whatever it takes is what has to be used. For instance, I am going to have to put a 30 Amp circuit breaker into my breaker box to accommodate the 30 Amp thermostat I had to purchase. But I HAD to have that specific thermostat based upon the size of the oven and the size heater I needed to heat it. Lots to think about. Of course, you don't need an oven this big but I liked the idea of having one I KNEW I'd be able to get the MOST use out of for anything of just about any size I'd use it for.
If the heater is the heart of the oven, then this blower is the lungs of the oven. This is a Dayton high temperature blower which is capable of withstanding and operating under high heat conditions up to the 750 degrees that the heater could produce. As I said before, I will NEVER run it anywhere near that temperature but I wanted to completely optimize what I bought and built so it would withstand whatever I gave it. And since we rarely ever go above 200 degrees, then this should last for the ages. This kind of blower will allow heated air to be recirculated through it without damage to the blower mechanism. The idea is to continually circulate the air - thus the term convection - that aids in keeping an even temperature thoughout the entire oven and heating the foam latex molds slowly and evenly. This renders better results when baking the foam latex appliances and preserves the molds without increased potential damage or cracking. And it makes the cool-down process for cooling the molds slowly, a much better approach to preserve the molds that have to be baked.
This little beauty is a Cooper vapor tension remote thermometer with a range of 40 degrees to 240 degrees. Basically it has a remote capillary with about a 7' coil that can be carefully bent to fit inside the oven at the optimal location to register the correct internal temperature of the oven and give you an "external" view on a 2" dial that shows the temperature. This is one of the ways you can use to keep track of the internal temperature of the oven while it's in use. And with the accompanying thermostat, you can keep the oven right where you want it in most cases. This isn't the only way to register internal temperatures but it's the best one. This is designed to give extremely accurate readings of how hot the oven is inside. I will also use high temperature oven thermometers from the store as secondary indicators of the temperature. I will likely have two more inside that I can view through a small "viewing" window in the door of the oven. This way you see what the temperature is at different areas inside the oven. Any oven has "cold spots" no matter what you do and these interior thermometers help determine where those cold spots are so as to avoid putting molds in those areas.
This item is a Chromolox Industrial Thermostat that can control temperature with a great degree of accuracy from 60 degrees up to 250 degrees. Naturally there was no need to get one to go beyond that since the oven temperature should never get that hot. What I didn't do, that I wish I had done, was to purchase one with a pilot light that when it was in use, I'd be able to see the pilot on. It's not a big deal because I can - and will - add the seperate pilot light when I install this. If I get a large enough light, it will be a good indicator of when the heater is operating and when it is at rest. It will only come on when the heater is activated to maintain the temperature inside the oven. This also has a 7' capillary element attached to it so you can reach just about any area of the oven. What has to be done is to find the area of the oven to place this capillary tube so it accurately registers the correct temperature inside and will then know when to come on and go off.
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Copyright (c) 1997 - 2010 S.A.P.S.E.M.A.(r)
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