How to make a simple hot wire for eps foam for surfboards

[tayloro]

HI all - I found this site on google looking for the subject. The thread I found seemed to be about machining surfboard blanks.

I am looking for a plan for a simple hot wire to cut 2# eps from block form. The cut would need to be up to 24" wide, and up to 6" depth.

Any help would be great. Thanks,Taylor.

[billp]

Taylor,
If you go to the Camp Shopbot Flickr page for the 2005 Southern California Camp you'll see a prototype foam cutter which Ilan Dei and Ken Zill were working on to cut surfboard shapes;
http://www.flickr.com/photos/campshopbot/126330677/in/set-72057594103500603/

[tayloro]

Thanks Bill - The part that is causing me the most confusion is the "power source." I have good plans for the "bow," but am getting mixed info on the need for some type of transformer.

Some suggest an AC to DC converter that also drop it down to @ 12V. Other suggest a variac to drop the volts down only, still AC.

One question I have: if all I need to do is reduce voltage, couldn't I use a dimmer switch??? Some say no, but not reallly why. Any thoughts?

Thanks - Taylor

[sam_harbold]

Taylor

Here are a few links that may help.

Power Supply http://www.nsrca.org/technical/tip_tricks/foam_cutter/foam_cutting_power_supply.htm

If you want to go high tech here are a few links to constructing a CNC Foam cutter.
http://www.homecnc.org/index.php/Cheap_Foam_Cutter
http://www.rcgroups.com/forums/showthread.php?t=184049

Sam

[kenz]

Here's what we use:
http://www.wicksaircraft.com/catalog/product_detail.php/pid=1425~subid=540/index.html

Can also be found on ebay. Search for variac.

[tayloro]

Thanks all - I am currently bidding on some variacs on ebay. Taylor.

[dray]

dont need a variac.. Use a 12v car battery charger and a dimmer switch.

Alternatively you can use a router speed control
http://www.drayconstruction.com/foamstuffs/