Step 2: Sawing

The final product will be a cube. The wood I used is 9mm thick so every measurement is made keeping the thickness of the wood in mind.

Saw 2 squares of 12x12cm, 3 squares of 10,2x10,2cm and 2 rectangles of 10,2x12cm, 4 little rectangles of 1x1,5 cm.

Saw 2 pieces of 3cm from a wooden stick (12mm in diameter).

<p>This is really pretty. Pretty dangerous too, as everyone already said. A bit more safety built in and this could be top notch :)</p>
<p>Incredibly innovative!</p><p>As an addition, I would like to suggest the formula POWER= VOLTAGE x CURRENT (P=VI). This will be helpful in calculating the amount of heat in Watts produced by the heater.</p>
Very cool.. I have ordered a fan from eBay but it is too weak to fit this project
<p>that's a great idea......</p>
<p>Great idea - I would like to suggest my twist to the project. Instead of springs, use 12V halogen bulbs. That would be safer, easy to get and easy to wire bulb connectors. Whats more it could also be used as a light source. You could beef the heating ability up as much as you want (by adding more bulbs). Also paint a thick coating of plaster on the inside of the wooden box, for a flame retardant.</p><p>Last but not least plugin a washing machine thermostat to control everything. That way you can sleep with worries of the heater becoming a fireplace.</p><p></p>
<p>Don't get me wrong, I like the idea, a neat little box that can give you a little extra heat. Great.</p><p>A random spring (even with a reasonable power draw) stretched across 2 terminals in a wooden box with no thermal or overload protection (besides what is in the power supply, which was not designed for this use), you're just asking for a fire. When that spring gets warm it will sag, it could contact something eventually, it will eventually break, you could end up with a very hot piece sitting in the bottom of the box (wood can combust at a little over 4-500*, that piece doesn't even have to be glowing hot &gt;1200*). Even if all that is OK, those fans tend to eventually fail/seize, sometimes from just sucking up a little bit of dust. Kill the airflow and that spring will get _a lot_ hotter, fast (though I would imagine that a little bit of airflow will fan the flames and make the situation worse if you can keep things hot enough to combust).</p><p>I generally refrain from being a safety natzi, mainly because I feel that we are way over regulated, no one assumes any personal responsibility, and heck, I don't always do things in the safest way. But this thing... If you're sitting right there and pull the power as soon as it starts smelling funny... well then it's fine, but you can get up for a minute, or heck, half the people that would look at this instructable and think it's a great idea would leave something like this plugged in overnight or over a weekend... </p><p>If you want to put a heating element in something like this look at how similar devices are made- typically a thermal shutoff, a position shutoff (turns off if it gets knocked over), overload protection and EVERYTHING near plus everything downstream of the heating element is made of non-flammable materials (and typically outside surfaces are insulated from the inside to prevent burns from direct contact to heated surfaces).</p>
<p>Even just one 12V inline 3A-4A fuse for the heating element, plus a thermal fuse for internal cabinet overheat, would go a very long way to making it much safer. At least that way, if the fan stopped or got blocked, and the current drain to the spring rose, or the internal cabinet temp rose, it would cut out permanently. Adding a far less flammable liner anywhere the hot spring might contact (like some recycled mica plates from old broken ceramic heater or toaster) would be good too. Or even some aluminum foil to reflect heat away from the wood (but that would add a whole other form of shorting issue). <br><br>I think if I made one, I might even just buy a cheap $12 cube heater and steal most of the internals from it to make a very safe low-power low-flow heater in a very nice box by using a 12V fan instead, but still using much of the other existing guts, which will still get slightly warm, but not very much @ 12V and very limited amps controlled by the PWM. And with the right controller, it could be pushed to 200W-300W and be a truly effective small desktop heater too and be very safe.<br><br>I do wonder why he did not opt to use a bank of large ceramic resistors as the heating element. They would be very safe, as they can suck lots of amps w/o getting too hot, esp not red hot like an exposed wire spring.</p>
<p>I agree, ceramic power resistors would be the easiest/cheapest way to do this cheap and fairly safely (you essentially have a ceramic housing around the coil to prevent stuff from catching fire somewhat, and there are a number of sources that people could harvest them from for cheap). <br><br>I'd bet that most people would have an easier time finding some sheet metal to prevent direct exposure of the wood to heat, but I'd bet that most people have a few ceramic tiles sitting around (or you can get ones for like $1 each or less at some hardware stores), which would work better and have no chance of causing a short (the only place to find cermaic insulators that you mention that I can think of is another heater...)</p><p>PWM would be a very nice way of controlling temp, the only part that I would disagree with is that it would be just as easy to build a 600-800watt heater with it than it would be to build 200-300, just use a cheap controller (you can find them for &lt;$10) and typically 5-60 or more amp SSR's cost about the same (between $10-20 on amazon or ebay), and you could hang the SSR's heatsink in the airstream to both cool the SSR and heat the air. With a 12VDC fan you can use the SSR to control fan speed with temp, so as you increase temp you move more air also...</p>
<p>Huh, the more I think about it the more I think I have the parts sitting around to make a really nice version of this sitting around. I think I have 2 small PWM controllers sitting around, and one or 2 60A SSR's that I have no immediate use for. I'm sure I have some power resistors sitting around, but I also have a pile of nicrome also... I also have a box of scavenged computer fans... I could weld/machine a really cool case for it...</p>
<p>Have you considered using large rectangular ceramic resistors (like those used in a power soak) as your heating elements? Being basically springs enclosed in ceramic (like Calrod stove elements) I think they would be a much safer alternative to a bare spring, esp. in a wooden box with limited airflow and no other safety features (fuses, tip-over switch, thermal liner, etc.). Of course, I also think you should add a few safety features, esp. two fuses, one current, the other thermal eve with the safer resistor.</p>
<p>Yeah I don't like the design much....<br>.<br>Too many things to go wrong, bad design and no safety / protection features.<br>.<br>The wire should be nickel chrome high heat type wire - not steel. It should be supported by regular &quot;stays&quot; along it's suspended length.<br>.<br>There are no thermal cut outs - such as a thermal fuse (fail safe off switch) @ 75*C and a thermostat / thermal switch set at 40*C.<br>.<br>The fan should have a free flow THROUGH the device, and not be trying to flow through tiny orifices.<br>.<br>Also that power supply was designed to drive a particular load, in a particular way - hooking it up to a wire that may or may not burn through by simple resistance - may be a dumb idea.....<br>.<br>As a previous person noted (mpikas) - some people really do have shit for brains** and or they very limited design experience - and this is just onselling a death trap device.<br>.<br>I just see &quot;house fire&quot; written all over this.<br>.<br>Personally speaking - I'd be using wire wound ceramic resistors in a series / series parallel array - of the appropriate ratings, in terms of power dissipating and wattage - and under driving them by 50%, and I'd be adding in a thermal switch with a low power filament globe in parallel with the switch to give a very long life to the contact, and I'd add a thermal fuse as a kill switch - like for when the cat leans against it and the thermal switch happens to stick closed...<br>.<br>Ideally wire wound ceramic resistors for something like this, should be uncomfortably hot to the touch... not exactly like boiling water, but not luke warm either. <br>.<br>And go and study an old clapped out hair dryer AND a fan heater.... and do some RESEARCH on the subject.... of the units and all the components.<br>.<br>.<br>.<br>**&quot;Shit for brains&quot;? - Yes there really are people who do go looking for gas leaks in the basement, or they want to see how much fuel there is left inside a fuel drum with a cigarette lighter....<br>.<br>https://www.youtube.com/watch?v=KgjI4PacHgk.</p>
<p>does anyone know if you can connect a 12volt car lighter to it?</p><p>also could you just do the cooler on a 9v battery?</p><p>if yes on both i would love to make 1</p>
<p>9v batteries can't provide much curent. I reckon the heating elemement would try to draw more current than the battery can produce and this would mean the fan wouldn't turn at all. It would be a bust. And a 12v cigarette outlet should be able to provide 30 watts. Just chck your fuse first to be sure.</p>
<p>A cigarette outlet uses a 15 amp fuse in case you want to figure out the max wattage capable.</p>
<p>Aside from the fire hazard issue, make sure the wood is real, untreated wood, not plywood or composite. Otherwise, heating it and breathing the fumes is a great way to poison yourself.</p>
<p>Well done! That's a nice little project and after rummaging around I have many of the parts on hand. Good job, keep going.</p>
This device is totally illegal in the United States. I can not speak about other countries. It is a fire hazard of the first order. Even if it were not illegal, a wood box for an electric heater is absurd.
<p>I like the look of this design but am I the only person who thinks it might also <br> make a good firestarter? Commercial fan heaters have a safety cutout if <br> the fan fails or the temp rises too much. Firestarters don't.</p>
<p>Anyway you'd just sell them on Etsy?</p>
<p>Nice. I was wondering what you would do for heat. I have a 69 Chevelle with a rear window defogger. It blows ambient air at the rear window so it doesn't do much actual defogging and zero defrosting. I had initially thought if a ceramic resistor but I don't know much about generating heat safely and this seems like a solid idea.</p>
<p>Those 12v car lighter have a heating core made of NiChrome (Nickel/Chromium) wire. Less amps, more heat. </p>
I like the look of the wood box. It might be fun to hack in a Peltier heating/cooling element. I have no design to offer, but... Here's an example device that will raise the required current to 6+amps, but might be useable with the proper aluminum fins... <a href="http://www.amazon.com/TEC1-12705-Thermoelectric-Peltier-Cooler-40mm/dp/B002UQKEU8/ref=pd_sxp_f_pt" rel="nofollow">http://www.amazon.com/TEC1-12705-Thermoelectric-Peltier-Cooler-40mm/dp/B002UQKEU8/ref=pd_sxp_f_pt</a>
man is there any way to increase current in TEC1- 12706 .. I used pc 300w power supply 12v which capable to give20amp but peltier takes only 3amp. <br>and the other thing to control the temprature on off switch ... i have some thing idea about this but main problen is to draw more current..
<p>how much heat does this produce? I tried a proof-of-concept without the fanc wooden enclosure and the spring was drawing about 5 amps, that's 60 watts, but when the fan blew on it it just cooled it down and barrly any heat was actually blown out by the fan.</p>
This is really cool, I'm going to make one for my mom who hates the cold. So not to overcomplicate it can I just hook a computer fan and hair dryer coil to a 12v cord?
<p>I would assme a hair dryer coil is designed to run on mains power (120/240vac) so connecting it to 12v will produce minimal heat.</p>
This is so clever! I would love to have a portable heater at my desk. In <a href="http://www.summersandsmith.ca" rel="nofollow">markham, heating</a> is necessary. It can get super cold. Thank you for sharing!
This is way awesome! I've been looking for a <a href="http://www.thegentlemenplumberslethbridge.com/heating.html" rel="nofollow">lethbridge heating</a> that sells heaters like this, but I'm gonna try this one. Thanks for sharing!
Please, METRICS are no good to us here in the USA. No one wants to convert all those metric numbers to USA INCHES &amp; FEET !
Great stuff! I can't wait to try this <a href="http://rafailhvac.net" rel="nofollow">heating in bridgewater nj</a>, my hometown.Thanks!
Thanks for posting this. It would be great to do this for <a href="http://www.thegentlemenplumbersedmonton.com/heating.html" rel="nofollow">heating</a> my desk in Edmonton.
UK PWM Fan Controller <br>http://www.shinyhardware.co.uk/prods/showprod.asp?pid=18732 <br> <br>Cheap and decent, I bought one ages ago.
Wow this will definitely help with <a href="http://www.summersandsmith.ca" rel="nofollow">heating</a>!!! Thanks for this.-Markham
I really like this idea. I am needing to find or make some kind of <a href="http://www.metroheat.com/en/heating.html" rel="nofollow">heating in Toronto</a>. I will try making this. Thanks.
That sounds and looks like a fun project. My son would like to build one of those. I wonder if <a href="http://www.summersandsmith.ca" rel="nofollow">markham heating</a> has heaters like that.
man i love the look of it i wish i could make one i will try someday
Link to where you bought the PWM dimmer module?
Would this dimmer switch work instead? It isn't labeled as PWM <br> <br>http://www.ebay.ca/itm/120782777352?ssPageName=STRK:MEWAX:IT&amp;_trksid=p3984.m1438.l2649
It is really a pity my supplier won't ship outside Europe, it is really a good product. If you are just going to use the fan the dimmer you mentioned (I think) will work. But with the heating element installed the dimmer will burn down. You should calculate how much amps all your components need and than buy a proper pwm controller, but don't spend to much money on it. On ebay type pwm controller. &nbsp;Here is a similar product <a href="http://www.ebay.com/itm/12V-40V-24v-36v-3A-Pulse-Width-Modulation-PWM-DC-Motor-Speed-Control-Switch-/110888220149?pt=LH_DefaultDomain_0&hash=item19d173f5f5" rel="nofollow">http://www.ebay.com/itm/12V-40V-24v-36v-3A-Pulse-Width-Modulation-PWM-DC-Motor-Speed-Control-Switch-/110888220149?pt=LH_DefaultDomain_0&amp;hash=item19d173f5f5</a> &nbsp;
If 30 watts is working for you, that's great. My experience with portable electric heaters is that they are usually rated around 1500 watts, maybe with a &quot;low&quot; setting of 750 or 1000 watts. I've used a ceramic-element heater which, once up to temperature, would settle down to 400 watts on its &quot;low&quot; setting. This was barely enough to keep a small room warm.
Yes, I know It just gives a warm stream of air nothing more nothing less. Just like I said in step 5.
Finally, a project that interests me enough to build. Only thing that concerns me is the safety aspect of it. When I build mine I'll put a couple more of safety features in it.
Well if you want more heating power, just add some more springs in paralell... just be careful it doesn't heat too much. <br>
Congratulations on a polished product and documentation. <br> <br>Your drilling was perfect not just with pattern spacing, but also for smooth bore holes. Wasn't till I saw the close ups that I could tell it wasn't laser cut. <br> <br>I'd suggest to anyone else that they clamp a piece of sacrificial board to the front faceplate, to avoid splintering when the drill bit punches through. <br> <br>Other suggestion is to skip the heating element and buy the right sized 12v light bulb... An incandescent bulb is a heater, light, resistor, and safety fuse all in one.
Yeah, but then it is icky nasty incandescent light blasting out of the vent holes and you wouldn't be able to see the LED. <br> <br>Also with those long power bus bars you could easily add one or two more springs in there to get a little bit more heat blowing through. Plenty of space in there, but obviously the power requirements go up. <br> <br>GREAT JOB!
I might suggest that some nichrom wire would make a better heater element. The spring is likely to fatigue or just burn out . <br> <br>I would suggest a sensible fuse in the circuit is a good protective device in case of excessive current. <br> <br>Is putting a heat source (30 watts is quite a lot) in a wooden case advisable?
The spring does not burn down; the fan keeps everything cool. You can see it as a hair dryer: 2000 watt in a confined space still the hair dryer does not melt down. <br>My design is like putting a 30w light bulb in a open wooden box with a fan on it. <br> <br>But yes nichrom wire would be a better option. Also a tilt switch is advisable so everything shuts down when the box is putt on his back. <br>
Yeah... nice design...<br> <br> Tilt switch = good<br> <br> Thermal fuse appropriately located near the resistance heater&nbsp; = good + necessary.<br> <br> A way to clean the dust and crap out of it every year or so.... Fluff and dust = fire hazard.<br>
Hair dryer coils are made of nichrome. You can find the stuff pretty cheaply online if you look. http://jacobs-online.biz/nichrome_wire.htm has a nice calculator for determining how much of what guage you would need for your particular application.
Just go to Salvation Army and buy and old hair dryer to hack the coils out of it.

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