Group,

I am trying to come up with a good power source for a foam cutter. I have pretty much decided that using a variac (10amp 0-140vac) feeding an isolation transformer then to the bow would be good, but am open to suggestions or other ideas. Also, I most likely will be using .020 stainless wire for the cutter, unless a better suggestion is offered. There are so many designs for cutters out there, but experienced user comments would be greatly appreciated. Thanks.

Joe Bennett

The required voltages are low, so a AC Variac is a bit of overkill. Most designs are based on a low voltage transformer that is fed by a cheap wall lamp dimmer. Here is a link to a popular design that I hear works great: Foam Cutting Power Supply

thomasb,

THANKS!! This will save a lot of hassle and most likely money too over the variac and etc. design. I will let you know how it works out. Now, what do you know about having to use Nichrome wire? I have heard that stainless steel would hold up better than Nichrome. Main thing is to control the heat, and with the unit you have directed me to, it looks like that aspect should be under control. Will have to compare the resistance per foot between the two and see what it is. Again, thanks.................

Joe Bennett

Stainless aircraft safty wire works great.

Aircraft safety wire works OK. If you can't cop a few feet, it's an investment to buy a whole one-pound spool.

For a buck and a half, you can get stainless steel fishing leader at Walmart. It's thinner then safety wire, and straighter. Safety wire is full annealed. Fishing leader is hardened and much less curly than safety wire.

For a power supply, I used a radio-shack 6V power transformer, a ceiling-fan variable speed control, and a toggle switch. The ceiling fan speed control will take the inductive load of the transformer, where I feared thet a lamp dimmer, which is designed for resistive loads, would not. The components are all stuck together in a radio-shack project box, with long wires and alligator clips to connect to the hotwire.

Or you can go to Lowes, or Home Depot and by mig or tig stainless welding wire. A lifetime supply spool for around $10 or $15.

Vince

thomasb,,,,,

Thanks for the link... it was best i've seen yet!!! do you have a link that is equally good for a great bow design?? Thanks again

There is useful info here:

http://www.charlesriverrc.org/articl...m_vac.htm#Bows
http://www.charlesriverrc.org/articl...foamcutter.htm

I have a variac stashed somewhere. I have saved it for many years, just to do some foam cutting.
Well, When I need it, I couldn't find it, but I did find an old AstroFlight power pack battery charger.

I set it up with my home made bow (.014) fishing wire. and it works great. the power on this charger is adjustable, so with a little playing around I was able to get a very nice smooth cut.

Waht is a foam cutter & what is it used for ?

Cheers.

Arjun