I had a thought about this. I'm no expert in fluid dynamics or anything,
so this could just be totally wrong. I will hopefully testing my version
of the hot air pencil tonight (if all goes well).

Anyway, my thought is this. Perhaps the reason Lawrence isn't getting
hot enough air because of the way he is modifying the airstream. I don't
know how the pump with the built in control works. Perhaps it just
squeezes the hose or something, thus narrowing the stream of air,
increasing the pressure, and decreasing the volume of air. Just
decreasing the voltage to the pump would seem to me to just decrease the
volume of air without increasing the pressure.

Ok, that was likely wrong...tear it apart :)

Josh
--
A common mistake that people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools.
        -Douglas Adams

Matt Pobursky wrote:
> I'm using a Million Air MA-200 pump for my hot air tool and don't have
> any trouble getting mid-400:F air @~1cm from the tip, using the lowest
> air flow on the pump (it has a built in control). It works great with
> Kester 276 solder paste that Digikey sells. The air flow is quite gentle
> and will reflow an 0805 chip resistor or cap in about 4-5 seconds
> (without blowing it around).
>
> I purchased it for a whopping $6.99 at:
>
> http://www.petdiscounters.com/aquarium/air/pumps/ca_ma200.html

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