Hello Rcindia,
i am bulding a hot wire foam cutter using a 12V/5A transformer. but i need a nichrome wire. i knw guitar string is also good but nichrome is better.can anyone tell me where can i buy it online r does anybody have it.i hope i get replies.
kartik.

Just buy the Cheap electric Hot Plate replacement coils for Rs10/- from local electric Shop. It has sufficient  length of nichrome wire for 4-5 hot wire bows of length 4-5ft each. Only Problem is that it is in the form of a coil and needs to be straightened to be used in the bow and when cold it has good tension and takes some effort to straighten.

To straighten it without much effort easiest method, if you have your transformer ready is to fix one end to a vice or the bow itself apply one end of 12 -24 volts and apply other end of the 12-24 Volts to the required length of the other end of the coil with a plier and stretch when it has heated up and connect to the other end of the bow with tension. It is very pliable and expands easily when hot.

If you find that the wire stretched by this method is not absolutely straight due to lack of tension in the bow or due to expanded wire wire under heat, reduce the length of the wire in the bow and increase tension and further when the wire is hot just stretch and drag a metal pin, like a stem of a thick screw driver over the wire two to three time which will straighten the wire absolutely smooth. You will have to reduce the wire again now to increase tension.

srry uncle i didnt get u.hot plate replacement coil???.can u come online on facebook and explain. i just sent u a friend request!

HELLO KARTIK,
just buy a Heater filament of 1000 watts from any electrical shop as said by sunderam sir. further, if u can get a fan regulator, (a chinese one will cost not more than rs25), add in series to the input of transformer.

Just straighten coil wires by stretching and finally rubbing it aroung any wooden corner(like of door)..

Take required amount of wire(not more than 0.5metre ). fix the two ends of wires at some rigid support., providing it at max tension u can(the reason being the wire expands when heated up)

Join the two ends with transformer output.

And u are done. U can regulate the temperature of wires usinng fan regulator..


Note: my brother makes a wooden bow "DHANUSH" using the wires at position of string. It works great.

i know the setup man!jst wanted nichrome wire.neways thnx for the filament one!

Here are the photographs of the heater filament for you

Done sir.nd thnx a lot!!!!

u can also open electric Iron element.Its identical to first two images. the wire you will get will gave a rectangular crossection.

Just go to the shop and ask for 1000 watt heater element(it will look like the last image).

U can also open up a soldering iron element.

 

sundaramvelar sir,
please correct me whether these are heating filament or element(which we call generally)..

thnx a lot abhay bhaiyya~

Quote from: abhay1290 on May 31, 2011, 11:56:42 PM
...U can also open up a soldering iron element. 

Is the soldering iron filament made of nichrome? Is it as good as the electric-iron one?

Soldering Iron elements are made of very thin Nichrome wires because of their smaller size, which cannot be used on a Bow.

@Abhay, I Think it should be call Heating Element from what I know 

Sir, exactly what is an 'electric Hot Plate replacement coil'? Is it used in electric-iron? What should I ask the shop-keeper for?

Local poor man's Hot Plate available any of the local electrical shop for Rs 100-150/- should look like this

The Brown Color Element is the Nichrome wire.

Taking out Nichrome wire from heating elements of various appliances is not a good option in my Opinion, One it may not suit the thickness required and second it will work out very expensive.

I bought a spool of Nichrome wire from a local Industrial store that worked out very inexpensive for me and would last for 'N' number of days.

Great Idea!!!!

Local product name for what you Bought and Brand name please.

Local name is Nichrome Wire. It comes in spools like those of copper wire. And It do not have have any brand on it. Because it is for Industrial use.

Can one get it in any 'electricals' shop or only a 'local Industrial store' ?

Hi Swapnil,
               I think it should be available in industrial electric stores, as it is used in industrial heater applications.

Nagpur being a industrial city there, should be no problem in getting it, just you have to roam around a bit.

Any ways I can send it for you, if you want it from me.

Darn, I just bought an electric-iron coil 20 mins ago.
Anyways, how much does it cost?

hi Swapnil,
               no cost just PM me your address and I shall arrange to post it to you. please also mention length required by you.

Sundaram sir, Kartik if you people also require Nichrome wire please send me above mentioned details.

Thnx a lot akshay bhaiya!

Thanks a lot from me too!

So, here's my hot-wire cutter.
Ripped out the nichrome coil from an electric-iron heater (750 W). Got a straight wire of approximately 2.5m. Took out a 15V transformer from an old cassette player. Initially tested with 1000W air-cooler regulator in series. Works best at max. power.
The alligator clips have flattened jaws. Gonna add a tension adjusting mechanism soon.

It works better than I had expected. Cuts foam like cheese! 
A year ago I tried cutting foam with a cutter blade attached to a soldering iron which didn't work so well. Had been using saw blades since. Now I have a hot-wire cutter too!    

Nice job Swapnil, Your frame is really nice. How do you made it.

I think you will be needing a spring or two at both ends of your frame to tension, nichrome wire, as it will expand once heated. It will sag and loose it's tension.