can i use a emergency light battery for hot wire cutter?
specs.
6v 4.0h
suncapak batt.
pls.

Noooooooooooooooooooooooooooo
4 amp will be very high................ and 6 volt will be very less to heat the wire...

Sandeep

i have the thinnest guitar string for the cutter which is note E maybe

Quote from: sandeepm on July 11, 2010, 10:13:20 AM
Noooooooooooooooooooooooooooo
4 amp will be very high................ and 6 volt will be very less to heat the wire...

Sandeep

A 4 Ah battery does not mean it will provide 4Amps, It can discharge in almost 10~20 seconds in short circuit condition and destroy the battery. It depends on the resistance of the wire.

Nah.. emergency light battery will not be enough i think.. but then if u already have it, why not give it a shot? might work for a small string.. and i tested the e / no.1 string (thinnest).. and it was about 0.5 ohm per inch..

so for a 30inch string.. 15ohms.. V=IR therefore I=V/R or 6/15 in your case i.e. 0.4 Amps.. I don't think 0.4A will be sufficient to cut.. My string was 0.5 ohm per inch.. yours might be different..

I am uploading some pages from RCSD Nov 2008 Magazine for all who are interested in foam core cutting.
" http://www.mediafire.com/?ji9a9h1b945r888 "

Surprised that Rao Garu has not added to this thread. He is a past master at the art of foam cutting and hot wire bows. Rao Garu, please help............

Quote from: prateek13 on July 11, 2010, 10:00:29 AM
can i use a emergency light battery for hot wire cutter?
specs.
6v 4.0h
suncapak batt.

With 6V you can heat  max 60 to 70cm of nichrome wire to desired temp to cut foam. if the nichrome wire is longer it will not heat up to desired temp to make a sustained cut. Voltage is directly proportional to the length of the nichrome wire which can be used. 

Dear VC,

I am unable to attach the Foam Cutter setup to PM.So I am posting it here.

Rao

Rao Garu, thanks a lot. This is exactly what I wanted.

Sir,
Could you please explain, why do we need Fan Regulator?
Regards,
Dileep

To adjust the current and hence the heat..

A variable adapter can also be used for this purpose, thats what I had been using, and it serves many purposes too...a handy little electronic box.

Guys pls post some pics of ur hot wire cutter..

I just tested my cutter.. The way the wire cuts through the thermocol is awesome!  I used a 12v 5A transformer and a old regulator that my electrician gave me for free.. Tried the thinnest (1 or e) and second thinnest (2 or B) guitar strings.. Although it cut through the thermocol, it was too slow for my satisfaction even though the regulator was turned all the way up.. So then we tried with a shorter segment of the 2nd wire.. It cut quite fast, so we realised that the strings have too much resistance and so we'll have to use thicker strings for a longer cutting bow.. Cant use thicker guitar strings as they have a coiled wire covering them.. Will try with thicker violin strings day after tomorrow.. Will be posting pics and vids later tonight.. 

Sorry I couldn't post pics and vids as promised in the last post as I've lost my data cable.. Anyway, I managed to find a thicker single strand guitar string (No.3) and it still has too much resistance.. Can anybody tell me where I can buy some nichrome wire?

Something like the following with 1 Ohm/foot would be perfect for my application.. If I don't find it in India I'll have to resort to ordering it from ebay USA..
http://cgi.ebay.com/Resistance-heating-wire-Nichrome-22-awg-20ft-/170484606532?pt=LH_DefaultDomain_0

Just look in the topic "EPP SHEETS IN INDIA",they r selling nicrome wire..

Quote from: xxkrishxx on August 18, 2010, 08:55:24 AM
Just look in the topic "EPP SHEETS IN INDIA",they r selling nicrome wire..

I have sent a PM to them.. Lets see if they have a wire which I can use? Does anybody know any other source of nichrome wire similar to the one in the eBay link above? It would be really nice if someone could send me some.. Otherwise I'll have to purchase it from eBay USA which I don't want to as I'm thoroughly sick of waiting for stuff to arrive from far away places

I get my nichrome wire from our school physics lab
its also better than the one avaiable on ebay
has Diameter od 0.32mm
Specific resistance- 1.019 ohm/meter
its the best wire i have come accross for foam cutters

Akky.. Any idea where I can buy that type of wire?

No idea medicineman ....i paid Rs 180 for the whole Role of wire
around 50 meters
i gave the money to our physics lab incharge

Medicineman!
why dont you try Furtado's?
you can get guitar strings there OR you can peel up a copper wire, which mas a approx. dia. of around <0.5 which should also work, I remember making a wire cutter like this during christmas for cutting thermocol!

Quote from: controlflyer on August 18, 2010, 03:58:49 PM
Medicineman!
why dont you try Furtado's?
you can get guitar strings there OR you can peel up a copper wire, which mas a approx. dia. of around <0.5 which should also work, I remember making a wire cutter like this during christmas for cutting thermocol!

Hi Dorwin, I've already tried the 1st 3 guitar strings but they don't heat up enough.. The other guitar strings are only available in the coiled form.. Violin strings are also coiled. Now will try some other musical instrument or copper wire..

Quote from: akky on August 18, 2010, 03:56:26 PM
No idea medicineman ....i paid Rs 180 for the whole Role of wire
around 50 meters
i gave the money to our physics lab incharge

Akky, could you buy some for me and ship it?

but how will you pay for it ,,,i dont have any bank account