Specific question about my hot wire cutter, help would be greatly appreciated!

I’ve been on the quest to make a hot wire cutter. Before I had a
transformer I got out of crappy old stereo rigged up with a dimmer
switch. For the wire I stripped the cover off a wire and used one of
the many from inside. The bow was about 2 feet long. It worked, but the
transformer crapped out pretty quickly.

I’ve read of many people having success with a car battery charger so
today i went to Canadian Tire and picked up the Eliminator 6/4/2
Intelligent Charger. Here’s a link.


Using the same bow and wire rigged up to this car battery charger, wire isn’t even getting hot.

Could this possibly be the wrong charger I’m looking for?

Any thoughts would really help!

i just looked at the pics of the variacs, do you get a power cord, cut it and attach the alligator

clips to the exposed wires and plug the other end into the variac?

Jesus, Greg, Mike, Buddha, or anyone…,

  1. if i buy the variac, how do i hook it up to the cutting wire? will it be obvious if i look at one? i

understand the aligator clips on the bow side but what about on the variac side?

  1. let say i tack a masonite rocker template to each side of a big block of foam… are you dragging the

wire on the rocker template? it doesn’t snag and break? or is that the purpose for the bobbins (Jesus)

and you are using a set block width each time so that the bobbins ride on the rocker templates???

thanks for all the great info guys.

Hey backpack

I’m by no means an expert with this subject, but the one I made from a car battery charger worked OK. I see that the model you have has two different amp settings, have you tried it on both? Also is there a safety cutout switch? Reset it if there is. Also try different wire maybe. Are you getting good connections everywhere? Is there a reading on the charger? Is it putting out?

I tried both settings. Didn’t see any other type of switches. Was no read outs. Going to return it today and get a full manual one. I’m thinking maybe that has something to do with it. Also a few different types of wire.

Here’s a link for the one I’m getting.


Thanks for the reply!

I currently (still) use a car battery charger for my hotwire harp. Mine is just an old crappy manual thing with no switches or settings. It works good. I posted some picks of my setup here awhile back. I’ve searched but can’t find that old post. The trickiest part for me was finding the right type of wire. I tried probably 6 different kinds. Finally found oe that worked at Harbor Frieght for about $3.00 a spool. It worked the best, but I had to set up two fans to blow on each side of my foam to keep the wire cool or it would snap. The wire only gets red hot where it’s not contacting the foam and this is where it would always snap. The best wire to use is NiChrome, but I couldn’t find any locally, and I wasn’t patient enough to order it. Then I found out that most hair-dryers use NiChrome (or something similar) as a heating element inside. So I went to a second-hand store, bought one for like $1.50, took it apart and uncoiled the wire inside. It works great, haven’t snapped one yet, and I don’t have to run the fans anymore either. I’ll try to find the pics of my setup if you want to see them. But in my opinion, your battery charger shoud put out plenty of juice to heat a piece of wire.

Anyway, hope that helps some.



Found one of my old posts where I was asking some of the same questions as you are. Still can’tfind my pics though. Oh well, maybe some of the info in this thread will help you out:





I like NiCrome best too. 25 gauge is my favorite. You can buy variacs online for about $55.


BTW did the dimmer out of your stereo go to 11?

If you’re using a fixed current source (no variac), then your control of the heating is only by the length and type of wire. Since you may be limited in how much you can adjust length, that leaves wire material and gauge as controllable variable. We use stainless steel fishing leader wire because it’s much cheaper than ‘‘specialty’’ wires and it seems to break less. Easy to find, too.

If you use the dimmer with your charger I guess you’d get some current control, but then I’m no expert on electricity.

Return the battery charger and order a variac for 50$. http://www.circuitspecialists.com/prod.itml/icOid/7674

Then get some ni-chrom wire. http://www.demandproducts.com/wire.php

I use a guitar tuner on both ends of my wire,the traditional gator clips,and sewing bobbins from michaels hobby and home depot welding tips inserted in the bobbins so the bobbins dont wobble,just a few taps with a hammer and they fit perfect.Just remember this adds about 1/4" difference in which your wire rides on the blank so adjust your foil templates accordingly.

I also use this little cutter for my outline,I cut a rough outline with a handsaw about an inch from the line,then I lay my template on the blank and the top of this bow sets flat and the roller and wire cruise along the edge of my template leaving a perfect cut.

It’s worth the $$ to get the right tools if you plan on doing more than 1 board.

Nice Jesus. Good info too. Thanks.

Thanking Jesus? … Mmmmmm

Got her going now!

Thanks for the tips everyone. You guys rock!

Hey Greg,

Does that 3A variac have enough output to split a 10’ blank lengthwise (for a stringer)? Or do you think a 5A would be better?

Thanks. Eric

I’m not Greg…but I have the 5amp and only have to turn it up to 8 or 9 when foiling a blank.It goes all the way up to 130,I think a 3 amp would have plenty of power.I haven’t seen a 3 amp anywhere,what’s the price on one?

Thanks for the observation. If you look back at Greg’s first post (actually his second) on this thread. He posted a link to “electroniccity.com” The variac in that link was a 3A and I think they were asking $55.

I have a 3amp that didn’t work for me - kept blowing fuses… must be my crappy set up, got a 10 amp and it works well most the time - I’ve blown a fuses… my hypothesis is, the “juice” “leaks” and thus the extra draw blows it…

Anyway - I’ll let the 3 amp go cheap. It worked on lights, and drills, but kept blowing fuses as I said, but, as I said, my bow set up probably isn’t as it could be…

All good info here - about the bat. charger… I bought one, and it had a ground safety deal, so it wouldn’t work. I just run the wire over my guide - which later becomes my stringer… can burn if not careful, but haven’t’ broken the wire.

I’ve used 3A and 5A and both worked fine. If you have the shaping video it shows the splitter for doing the stringer cut. We use a 3A on that at about 90 volts with a 24 gauge Nicrome wire. Splits them perfect and your ready to glue up without any other prep work. Variacs used to cost around $150. We’ve burned up a bunch of them … but we have made literally hunderds of thousands of blanks. Then they stated being made in China and now their cheap and well worth the money even for a home builder.