Get on with it ! Kids, don't try this at home

09 Aug 2007 I've gotten sidetracked from the vacuform construction process. One late night I though it would be fun to see what the heat distribution of my vacuform oven would look like, if I used 9 halogen linear tubes as the heat source distributed evenly over 1 m^2.

I went on to build a software simulator to generate some nice pictures of what it would look like. The first simulator was stochastic and the pictures were not really nice (see an older post). Version 2 of the simulator uses real physics to calculate the temperature change in each spot of the vacuform oven.

This picture is the result of that simulator:
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The color indicates how hot a certain spot is. This is what the gradient looks like:
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An AVI file is available here (900KB):
http://www.singularity.be/Trashcan/vacuform/heat-distribution-non-stochastic.avi

And an animated GIF here (2.3MB):
http://www.singularity.be/Trashcan/vacuform/heat-distribution-non-stochastic.gif

Here are all the files and the code (9.5MB):
http://www.singularity.be/Trashcan/vacuform/heat-distribution-non-stochastic.tar.gz

At this point I should probably say that I'm not a physicist or an engineer. So basically, I have no idea what I'm calculating when I do these simulations. They just seem to make sense as far as I know.

In any case, this is where I got sidetracked. After spending hours (and hours) on the simulator, I still don't have any reasonable results because I have no idea if my simulator even matches the real world.

So, let's just get on with it. Instead of using software to simulate the oven, I just built a smaller version of the oven.

These are the professional blueprints
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Apologies for not using the more standard cocktail napkin for this, but I had none handy.

By the time I got to the basement, the plans had already been revised (just to show how rocksolid my ideas are)
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All the wood was cut to length (and recut to length after another design revision)
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And some holes were drilled with my newly bought drillstand. This drillstand is actually quite handy. When putting together the vacuform frame, all the holes I drilled were out of alignment. This thing makes sure that all holes are straight.
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Of course, it didn't take long to break the stand. What do you expect for 25 euro ? :) I'm taking it back to the shop to be replaced. The stand was still good enough to drill holes though.
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The mini-frame I built for this experiment is actually better constructed than it's bigger brother. Using pre-drilled holes, I was able to put the frame together very fast
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And here is everything together:
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Allright, now we are getting to the "Don't try this at home, kids" part. So, Don't try this at home kids:

To mount the linear halogen tube into the oven, I made my own version of a lamp socket using a couple screws and bolts and some high-gauge electrical wire. At this moment, the oven will use only 500W (1 lamp), but when using 9 of them, it will suck 4500W. The wiring I use here is 4mm^2.

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When plugged in, the oven lights up nicely
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But after only 10 seconds, the wood started to burn
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I expected this to happen (really) and bought some heat isolation that is placed behind heaters to reflect the heat. I will put it in there later and try again. Stay tuned