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Hot Box Question

post #1 of 10
Thread Starter 
Why do people who heat hot boxes with light bulbs put the light bulbs at the top of the box?
When hot boxes are designed with heaters, the heaters are placed at the bottom of the backside of the box. This makes sense as heat rises.
My belief is that the goal is to provide an environment at a constant temperature of 125 - 130C.
I am building a hot box using light bulbs as a heat source. However, the lights are located at the bottom of the box. There is an angled deflector above the lights that is covered with reflective insulation to prevent radiant heat from reaching the skis with the hopes of providing a constant temperature environment around the skis.
If the light bulbs were located above the skis, it would seem to be less efficient and the skis closest to the light bulbs would have a number of hot spots equal to the number of lights.
Am I missing something?
post #2 of 10
The stuff I've been reading suggests temperature setpoints near half of what you mention...maybe I've been reading the wrong stuff? I would think the polyethylene base will begin to melt/oxidize/behave badly at those temps.

If you block the radiant heat from the lamps and circulate the air with force of fan like most setups I've seen do, it probably won't matter too much where the bulbs are. The bottom could be a wee more efficient (the top surface can be unbroken by conductive fixtures) but I imagine people put the bulbs on the top because it makes it more difficult to break them. If you are protecting them with a radiant shield that may be a non-issue.

Best of luck, the threads about this have excited me, perhaps this project could take the edge off the wait for snow.
post #3 of 10
Thats sound reasoning, and a good design, as skiingman said though you might want to verify those temps. You just want the wax to start to melt not melt the whole ski!

I used a heater for mine (at the bottom) with an automatic thermostat control and I backed it up with a digital and manual thermometer to ensure the readings were accurate.
post #4 of 10
Here's a nordic site with some plans. They use a small electric heater and a fan to distribute the heat around the box. Really neat. You might want to consider adding the fan to your light system. That should help keep hot spots from happening. It shouldn't be that hard an addition.

That site says 54 C which is 130 F for the temp in the box.

Here's another site with hot box info.

125 C is 257 F which would probably ruin your bases. Also, I'd hate to see the electric bill let alone the chance for the wax to catch on fire. :

Here's a place selling the Swix Hot Box. At $4K for the box, : : : : I don't blame you for making your own. You can make a heck of a lot of them for that price.

Thanks for starting this thread. It sparked some interest for me and I found some interesting information. Might even make one of these suckers myself.

This has been discussed before here. http://forums.epicski.com/showthread.php?t=20054
post #5 of 10
Originally Posted by quickk9 View Post
My belief is that the goal is to provide an environment at a constant temperature of 125 - 130C.
C : or F ?
post #6 of 10

Get with the rest of the planet!

but you are correct (if somewhat recalcitrant for using an antiquated unit of measure) in this case: 130ish F is good, 130ish C :would be good for your ski retailer.
post #7 of 10
Thread Starter 


I meant to right "F" not "C"! I apologize.
was waxing some skis tonight and mixed up iron temps with hot box temps. Applying Swix Base Prep at 130C with a digital iron should not be confused with hot box temps!
My goal is to allow the wax to soak in not sterilize (and delaminate) the skis.
After trying to convince friends that the temp wouldn't damage the skis, I posted incorrectly!
In the past, I've placed waxed skis in my sunroom, and I've monitored the base temps with an infrared thermometer and seen 125-130F, but I'm looking for a more accurate environment. I was concerned that the skis would get too hot so I monitored the base temps with an infrared thermometer.
I will post more info when I complete the project and get some results.
FWIW, never trust anyone who wants to hotbox your skis at 130C. They may make a fine cup of tea, but I would go elsewhere for ski tuning ...
post #8 of 10
Thread Starter 
Originally Posted by T-Square View Post
Great site. Although as for cost, all of the wood that I've used has been free - leftover from contracting jobs. The electrical equipment and insulation that I did have to pay for ran me around $200. This included the remote thermometer, 5 light bulb capacity, polysty insulation and reflective insulation.
All of the insulation may be overkill, but I am seeking a constant temp environment. At 130F not 130C ...
post #9 of 10
quick9 (or anyone), as I'm sure you are aware, direct gain passive solar systems (sunrooms) are hard to control, as the goal is to maximize gain when it's there, and store it somehow or move it to other areas of the structure you wish to moderate. Additionally, the insulation resists heat not just cold, so an insulated box, blanket, tent/rack system in a sunroom can slow down heat transfer in an block UV rays. With a fan and a thermostat, seems like you could regulate flow and temp within a box or whatever pretty easily.

Maybe your SO will really appreciate a 'window seat/hot box' in your sunroom or some other multi-functional approach? "Honey, what's that smell?" :

Seems to me that the temps we're requiring are in the same range as passive and active solar systems. Another reason to incorporate solar strategies into your homes and site planning....along with a dedicated gear room.

Originally Posted by Andrew R View Post

Get with the rest of the planet!

but you are correct (if somewhat recalcitrant for using an antiquated unit of measure) in this case: 130ish F is good, 130ish C :would be good for your ski retailer.
No question that metric is a smarter and intuitive system. But why let logic and efficiency improvements get in the way of major decisions? :

FWIW, here's quick & dirty 'reference thermometer' you can save to your HD, to help keep the C to F conversions straight (there are other conversion helpers on our site):

post #10 of 10
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