zachtheterrible said:
hmm, interesting, i like that hot air pencil.
That sounds like an interesting idea, thanks for posting the link.
Yesterday I started to make a hot air pencil after realising I had all the parts for it lying around.
I used ten turns of a junked bar heater element for the heat source and a small, vibrating type, air pump which once inflated air splints.
First try was using the glass tube of the bar heater as a containment for the element as I did not like the fragility and fire hazard of the exposed heater used in the original article.
The glass tube was too fragile, got too hot and could not be drilled for a connection to the element within. :cry:
Next I used a 90mm long teflon spacer, drilled out to 7mm, to suit the ten turn heater spiral. This was fitted with a turned brass nozzle (its nice to have a lathe :wink:, gloat). The nozzle had a 2mm opening at the business end.
The front end of the heater spiral connected to the nozzle, the aft end to a short 8BA screw through the teflon tube. This brings both connections to the outside, where I ran 20SWG tinned wires, heat shrink covered to the teflon spacer, to the rear end of the pencil.
The heater spiral can only be connected to by means of clamping, I used a longish 8BA tapped strip as an inside clamp nut
Findings: the air pump was way too powerful, cooling the element too much. An air bleeder was fitted into the ail line and this got the heater red hot with 80W of heater power. I use an adjustable 12V power supply for the power source, its good for 8 Amps
Further findings: the element was partly inside the teflon tube which started bulging alarmingly when the heat was turned up to red hot.
I will have to turn a longer brass nozzle that contains most of the heater spiral, which is where the project is stalled at the moment.
So, its not quite as simple as it looked at the outset :roll:
I will keep you posted if there is a successful outcome in the end :wink:
Klaus