Lead Sled Alley - December 2002

By Russ Thompson

You may have noticed the name of this column changed from "Crunchie Corner" to "Lead Sled Alley". This is because the word "crunchie" encompasses all non-foam airplanes, but "lead sleds" are, for the most part, what will be covered in this column. This month however, the column will cover something a little different. new

I use 110v to dimmer switch to 24v door bell tranformer (in a protective case) with great success then when I am doing different density foams (EPP, white foam) I get the voltage just right.
I also use a simple bow with fishing leader and it works great everything to cut a wing for 15$...it does take practice but the sled way does as well.

Good article, very complete.

Very nice article. My buddy and I built a foam cutter, but never had much luck with it. This gives me the incentive to go out to the garage (tomorrow) and cut some cores.

Pete

these work great. I've been using one for almost 20 years now. But mine cost way less that Russ'.

1 nail (free)
6' of stainless steel fishing leader wire (.016" from Cabelas, $6 I think for 50')
1 old electric train transformer for power (free)
6" off the end of a broom as the handle (free)

I just drove the nail into the end of the workbench.

TFLG

PS if you ever bought a Slope Scale warbird kit the wing was cut this way!

Yes, I think the stainless steel fishing leader wire is a good alternative to nichrome because it is much cheaper and much easier to find. Unfortunately, the charger I used in this project did not put out enough power to heat more than about 18" of it. I guess that's one more bullet in the list of benefits of using a better power supply - it would allow you to use the cheaper wire.

If you can find one, the electric train power supply is perfect for this application because it already has a variable DC output. Do you happen to know what the max output voltage/amps is on yours Brian?

Vinny,
I also like your idea of using a dimmer switch with a doorbell transormer. A 24 volt output would really help in heating a longer section of wire. My only concern is having AC on the wire. Can you touch the outputs without getting a shock?

Russ.

If you would like an excellent solution to powering up your wire go check out Fry's. The one in San Diego has variac's for around $25 to $60. I can't remember all of the spec's but I think the cheapest one would do the trick.

It's in a nice metal case with rubber feet, plugs into your AC outlet, has an on/off switch, and a dial to dail in any voltage within it's voltage range. I bought mine over the Internet (search for Variac's and you should be able to find one for sale near you) and paid a bit more but it may be higher quality. I may have also just paid too much

Happy cutting.

Originally posted by seafury_fb11
My only concern is having AC on the wire. Can you touch the outputs without getting a shock?

We consider <30 volts to be non-hazardous in normal conditions. (Don't stick it in yer mouth and go stand barefoot in the rain, ya know... )

mw (electrician)

Originally posted by Mark Wood
We consider <30 volts to be non-hazardous in normal conditions.

Thanks Mark. I wasn't really sure what the threshold was.

Russ.

I tried the type of setup that Russ and Brian use, however I was not successfull. It was quite a while ago and I don't remember now what went wrong, all I remember is that my cores were unusable.

Later, I got a good deal on a feather-cut clone, and I have cut some good cores with it. Making four templates (Two for each end), setting up the cutter, getting all the pulleys arranged exactly right etc, is a real pain. The best part is that after it is all set up, you just hit the power switch and watch the machine make the cut for you.

Brian sure makes it sound so simple and easy to cut cores his way! I think the simple setup might outweigh the advantage of the hands off cut. I might just have to grab a nail, some wire, and broom handle and try it again.

I use a 10 amp car battery charger as a power supply, with a light dimmer switch attached to control the power. This setup provides more than enough juice to heat up a 40" cutting bow with stainless wire attached. I only use about 2/3 of the available power.

I just ran across this thread in 'The Workshop' forum. I has a link to some cool foam cutting tools. They also have a couple of fairly inexpensive power supplies.

http://www.rcgroups.com/forums/showt...threadid=82448

Russ.