Kanthal Konfusion :)

[pipeman01]

OK, I've made a length of twisted Kanthal (0.30mm) and if I plug the values in steam engine (1.5ohm, 2mm ID and 5mm legs) I get 3.86 winds as a dual serial coil and 17.28 as a dual coil

What have I done wrong or how do I select the correct settings in steam engine? 

[toots]

pipeman01 I'm no expert at this, after only making my own coils for a few weeks, but I think for a dual coil set up you need to halve your resistance, so instead of putting in 1.5 you need to put in .75 which then comes out at 8.16 wraps

Edit: Oh and I forgot to say you need to put a figure in the twist pitch box - I just entered .35 as a tester figure, so you'd need to put in the correct figure there.

tim is the above correct? I can see you're online at the mo, hopefully you can pop into this thread.

[tim]

set the pitch at 0.5mm pipeman01

Oh, and you will need a lot of watts.

Do you know what you are doing? No offence.

[decoy]

erm er never built a 1.5 ohm coil with twisted wire that big
the coil would be huge

[ginge7289]

Is this what you're trying to do?


I agree with decoy

[chykensa]

pipeman01 - I don't use twisted much at the moment, but for a start 1.5 ohm is really very high resistance, and if you are dual coiling, you do need to halve the final resistance.
Here's a link to Steam Engine with the figures suggested above but aiming for 1 ohm - note that the best power to send through those coils is 120w!! (See the Heat Flux line in the Results box on the right hand side).

[pipeman01]

chykensa, I ended up with this:

www.steam-engine.org/coil.asp?p=roundmulti&tp=2&r=1&hfnw=30&str=2&dia=0.3&wl=94.89905020298607&id=3

I used your saucepan method to twist but didn't go mad (saucepan gets heavy after a while and I think I did too long a length... about 1m so it took ages to twist.

Reads 0.97 on a multimeter and 1.0 on the mod. Not sure I can discern any difference between this and an untwisted coil build of the same rating... should I be expecting a noticeable difference or is it just a variation on a theme?

[chykensa]

The advantage of a twisted coil is that there are more cracks and crevices for the juice to sit in, meaning more contact area when the coil is fired. I've never been too sure about the differences in resistance either! If it works, it works, provided I'm not pushing my devices to their physical limits. Maybe someone else an explain the difference between single wire and twisted twin-strand coils?
I usually use about a metre of wire doubled through my saucepan handle hole, hold the two ends tightly in pliers, allow the saucepan to hang on the wire, then just turn it like crazy until the wire snaps when there is too much tension on it. This usually happens at the saucepan end, so you have to be quick on the reactions to make sure the pan doesn't hit the quarry tiles on the kitchen floor! Only takes about 30 seconds to twist the wire, and then snip off the ends to tidy and away you go.

The only figure I would question is the twist pitch of 2mm. I always put in about .5mm as it's the distance between the tops of two neighbouring turns of wire once they have been twisted; this has to be less than a mm, although I don't have the precision equipment to measure it accurately, so an approximation suffices. This difference means another turn and a half on your coil, which may make some change to the resistance, but not a huge amount - perhaps .1ohm?

[hijack]

I kinda gave up trying to get steamengine to work out the resistace of twisted wire. I use .3mm to twist 2 strands though with a drill and I think 6 wraps on a 3mm former is around .8 Ohm (give or take) so duel coil 6 wraps each would be .4 Ohm.
Best way is make a 6 wrap single coil with the wire you made and attach it to the deck, measure it, and go from there.