can someone point me to instructions on how to make my own hot wire rig?

THe best way to do it is find a Variac, and hook it up to a 12 volt step down transformer. IF you dont use the stepdown, the adjustments will be WAYYYY too sensitive, if your finger slips, the wire will turn bright red and melt. Also the 12 volt stepdown will keep your Variac from frying.
As for the Bow, just design your own design out of PVC or wood, Make sure you can adjust the tension on the wire.
AS for the wire, use Stainless steal fishing leader wire. Its available in tons of thicknesses, and works much better than nichrome wire, despite what people will tell you.

[This message has been edited by BillH (edited 04-20-2001).]

I've heard you can also just use a model train transformer. I don't know what specs it needs though.

Dean in Milwaukee

BillH I am a little fuzzy on the 12v transformer, I use my Variac without one and have no problem (short of electrocution) with the adjustments. I just crank it to about 10-13 volts and cut away. It is a 15 amp unit I got from a surplus store for 125$.

http://www.charlesriverrc.org/articles_foam_vac.htm

This link should give you some ideas.
Ron

I use a 24 volt 3 amp transformer and the stainless wire. Nothing else but an inline fuse and it works great. Your cutting wire must be kept around 35 to 40 inches.
Adam

I'm using a speed controller and a 12V deep cycle battery _ things I just happen to have around the shop
(I also use a servo driver now but have run it with a receiver and transmitter)
I also am using stainless steel fishing wire for the cutting wire in bows made from 3/4" dowel and 3/16 spring steel. Dead simple and cheap.

cheers,

Martin

Dave, I wish I could tell you why, but my boss who is an Electrical Engineer told me to do so, or I would blow out my variac. I think he mentioned it had something to do with the impedence.

I connected two car battery chargers in series, and I adjust temperature by sliding one of the power wires along the nichrome wire (shorter distance between the wires makes the nichrome hotter). It's worked for me really good and all it cost me was a couple $ for the nichrome. I also had to borrow a second charger from a neighbor:-)

<marquee> hope this helps... <marquee>

[This message has been edited by maciek (edited 04-21-2001).]

Why I light dimmer?
DOesnt the Variac have an adjustable wheel you turn?

Originally posted by BillH:
Why I light dimmer?
DOesnt the Variac have an adjustable wheel you turn?

The transformer/dimmer is a lot cheaper than a variac.

ohh ok, makes sense, I thought they were using all three together

We're all flying electric planes, right? All I use is a seven cell battery pack and a homemade bow with .015 music wire. If the wing has too long a length of cut (music wire too long) for the seven cell pack, I use an eight cell pack. It works for a few cuts and then you simply recharge it. Works better if you have a couple of packs. I found a drawing of a bow on a german site.
http://www.jps.net/cobrajet/Foambow4.JPG

I use an Astro charger in "test" mode. You can dial in any current you want.

Aircfraft Spruce and Specialty they have a Webb site.. sell Variacs for $60 and an 'El cheapo' hot wire kit consisting of a largish 24v transformer and a household light dimmer for $18.
Laughably simple, easily home duplicatable.. and it really works, especially using "Controline" stainless wire, obtainable free from any CL flier.