Hot wire cutting

[Aclouston]

I seem to recall somewhere in a CP that the recommended cutting wire had been increased from .032" to .04x" did I dream this? Also what is the transformer typically used for this? 12v?, 28 or 48v? Any particular tension and wire temperature we are looking for?

Thanks

[Kent Ashton]

https://longezproject.blogspot.com/2011/12/ch-3-foam-cutting-part-4.html

My cutter is just like the one above, black pipes in a 2X4.  I tighten the wire by twisting the pipes with vicegrips and use one of these autotransformers as sold on ebay.  .032 safety wire.  It is possible to get shocked.  I never have and never heard of anyone getting shocked doing this but I wear rubber-soled shoes on a dry floor.  An isolation transformer is nice precaution--it would prevent the shock hazard--but most people don't use one.

Practice on pink styrofoam from the home stores.  It is nearly the same as what we use for aircraft but remove the plastic coating.  I am sure there are youtube videos.  This one is pretty good  https://youtu.be/WgxgcB57n9Y?si=ntsPHns3ysR-0XZL

 

Edited May 10 by Kent Ashton

[Aclouston]

Wow. I can't thank you enough. It's now on my father's day whish list.

Allan

[sixfivelrp]

Make sure you don’t substitute from the stainless steel safety wire. Here is my saw if you decide to get creative. Just as a starting point the my variac is set at 22 volts. Your setting might vary a bit. 

[Aclouston]

I love the design.

Look for patent infrigement on my part. Coming soon.

Unless you want to lend it to me?

Thanks

 

[Marc Zeitlin]

1 hour ago, sixfivelrp said:

Make sure you don’t substitute from the stainless steel safety wire.

Nice saw. But Nichrome wire also works great, and usually can be had in thinner diameters for a smaller kerf than the SS. Of course, if you use oversize hot wire templates and then correct size templates for the final sand to shape of the cores, the kerf is immaterial.