Whats the trick to clean Spar cuts?

[Burnt Offering]

I have been wondering how you experienced CnC foam guys get those pretty spar cuts. The trouble I'm having is this. If I have the wire hot enough to not lag the wire, it melts the crap out of the first foam it comes in contact with when exiting the spar cut. When the wire comes out of the slot for the spar, man it just melts the airfoil like crazy making me lose 1/8 or so for a little bit until the wire cools back down from foam contact. I can't find a happy medium on heat and wire speed to compensate. Are you guys doing a seperate pass for the spar cuts? Any advice would be greatly appreciated. Thanks in advance!

[cnccutter]

What speed, voltage, type wire....are you using?

[jhelmstetter]

Speed has a lot to do with it. Cutting foam with a hot wire, you want low feed rates a a wire temp just hot enough to "cut" the foam. Slow and cool... I know, I do the same thing if I am rushing. There is a document that someone created to calculate the amount of tension to put on your cutting wire based on some variables. I'll add it here.

[Burnt Offering]

Hey, guys, I just kept at it until I got it right, and you are right slow with low temp makes all the difference. I would still love to see the document with all the varialbes on it! If you would please post that. Thanks for the reply's!