From: Sam Nichols
Subject: Re: Help creating a heating element from resistor.
Date: Wed, 11 Dec 2002 14:42:32 -0800
User-Agent: MT-NewsWatcher/3.2 (PPC Mac OS X)
In article ,
> Sam Nichols wrote:
> > In article ,
> > wrote:
> >> Sam Nichols wrote:
> >> > nothing. I guess it might be closer to 4 oz which could still work. I
> >> > want to vaporize oil for a tiny smoke machine.
> >> > Anybody know a place that carries Nichrome in the Bay Area?
> >> Oh, it'll work.
> >> I'm just unsure as to for how many seconds.
> >> My gut says there is no way in hell you'r going to get enough energy from
> >> a battery that small to vapourise three times it's weight in oil.
> >> However, numbers are good.
> >> The first fog generator numbers I found were 20Kw evaporating 40l/hour,
> >> or 1Kw=2l/h. Maybe 1Kw/Kg/h.
> >> So, 60g of oil...
> >> Say you want to use it all in 6 mins.
> >> That's 600g/hour.
> >> So, you need a power source of 600W.
> >> That AA cell won't supply 500A, and it certainly won't do it for
> >> 6 minutes.
> >> The energy in an AA cell is about a watt hour, so you can evaporate a
> >> whole gram of fog. The oil container won't need to be very big.
> >> It'll produce about 20 cubic feet of fog a minute for 6 minutes.
> > Yah, you're right, I've come to the conclusion that a couple AA batts
> > won't do the trick, so I've modified the plan a little. Now I'll be
> > sucking off 1-2A from an already existing 8-cell battery pack which
> > gives between 10-12V. If anything it'll save me 1.5oz since I won't be
> > adding a 2nd battery pack for this smoke generator. Where are you
> > getting your numbers from btw? I was looking at some stats for Nichrome
> > wire and if I used 40 AWG wire looped around (probably a ceramic or
> > metal tube) the chart said I should get roughly 400 deg F out of about
> > 13 watts. I only need 240 to smoke my oil so I imagine I could tone it
> > down to 10 watts or less which is well within (1-2A)*(10-12V).
> If not doing anything.
> Oil takes energy to vaporise, I was getting the numbers from someone that
> sells large foggers, and was saying 9gallons/hour at 20Kw.
> I couldn't find wattage numbers for party foggers.
> If you could find those, and maximum fog juice flow, then you can work
> out better ones.
> Just like your kettle, if you leave it to boil, a 2Kw kettle will take
> around 20 minutes to boil away 1l of water, but the element if uncovered
> would heat to well over 1000C with the same power.
Good point. Well the Nichrome arrived today so we'll see what happens.
Which brings me to my next question, a 1A current source I can build