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Foam cutting help

Old 10-31-2002, 10:38 PM
  #26  
Ollie
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Default Foam cutting help

The greater the curvature of the airfoil, the greater will be the error due to wire sag. Wire sag can be eliminated by adjusting the temperature and speed of the wire so that it barely touches the foam but then there will be melt back of the foam that reduces its dimensions below the dimensions of the the template. In other words, a hot, slow wire will produce a kerf that is wider than the wire. The big advantage of the arm controlled cutters like the feather cut is that the weight on the arm and wire temperature can be adjusted to find a happy compromise between wire sag and melt back. Also, the bow must heavily spring load the wire so that the tension remains close to the breaking point when the wire expands with trmperature rise. The only way to have too much tension on the wire is to break it. The wire should take about 20 seconds to cut through 10 inches of foam.
Old 11-01-2002, 03:43 PM
  #27  
phuffstatler
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Default Tekoa?

I see no one has mentioned the TEKOA setup at all. Are they too pricy, too cheap, not the right thing, etc.? I really don't want to build all my own equipment, as I don't really have the space. I need something I can put up and take down rather quickly and easily...

Any thoughts?

Phil in Austin
Old 11-01-2002, 05:36 PM
  #28  
Ollie
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Default Foam cutting help

The Tecoa Feather Cut is a quality product with a corresponding price. If you don't want to build your own foam cutter or if you don't want to scrap a lot of foam learning to cut manually it is the product of choice. It produces quality results but takes some time and figuring to set up for each wing panel to be cut. For highly tapered panels it is much more accurate than any manually cut panels I have been able to produce with 15 years of trying. I still prefer the convenience of manual cutting for panels with moderate to no taper. My best manually cut cores probably only approach the accuracy of a Feather Cut core but certainly never exceed the Feather Cut's accuracy.
Old 11-01-2002, 07:05 PM
  #29  
Rubbie
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Default Feather Cut

I can't pretend to know how to cut foam, but after I bought Compufoil and the feather cut machine no body can tell. It is great, I tried to cut manually but never got it right, now I spend 5 min setting it up and I get a perfect core every time! Like other guys have said it is pretty expensive. It comes in a 3 or 4 inch shipping tube about 4 feet long and everything except the generator all collapse (even the bow) to pack right back up in it. I love it!! Now just need to find that perfect vac bagging machine and I'll be set!!! (but that's another thread)
Old 11-01-2002, 10:29 PM
  #30  
TOMMYSTA
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Default TEKOA

Dont forget now Roger has released some attachments that allow
you to cut fuselage parts. It's an awesome system...well worth the money. I have all 3 size bows and all the attachments. From any good 3 view with cross sections you can make templates and cut a complete plane. I've cut out the fuse and wings for an 85" span PT Stearman. It should come in around 10 lbs.
Its worth the money!!!
Tom
Ck out the website...TEKOA.COM
Old 11-02-2002, 01:41 AM
  #31  
Jaymom
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Default Foam cutting help

Looking for some help..... I just bought the PC Board Kit from Radio Shack. Instructions seem quite clear . My problem is that I can't figure out where the lines are to be drawn. Can anyone show me a diagram of these lines showing how they connect all the components please ! Many thanks
Old 11-02-2002, 01:51 AM
  #32  
B Vial
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Default Foam cutting help

If you have the picture of the PC board from the web site here is what you do. Make a piece of paper the same dimentions as required (2 1/2" x 4" I think). Copy the hole locations to them from the picture with the block layout diagram. Double check your hole positions against the components you bought from Radio Shack. Some holes may need to be readjusted and the Triac holes comes to mind.

Now the fun part. Look at the block diagram. There are multiple holes in the same block. On your piece of paper draw lines between these holes that are in the same block in the picture.

Think of it this way, in the picture of the designs curcuit board, he has you remove strips that make it so the components aren't hooked together. What you want to do is take your paper diagram you are drawing and hook the holes that are supposed to be connected by a metal connection that is represented by the picture being in the same block.

I hope you can understand this. I am not good at explaining things without being winded... lol
Old 11-02-2002, 02:24 AM
  #33  
Jaymom
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Default Foam cutting help

Well I'll tell you what B Vial, you make an excellent instructor. You made me see something that is so obvious that I'm ashamed of myself ! Many thanks, I appreciate your help very much.

Jaymom
Old 01-21-2003, 01:28 AM
  #34  
hover
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Default hot wire power supply

What is the range required for cutting up to 48" cores? I am looking at some variacs, but they are very high horsepower. If the price is right, are they of any use?

Kelly
Old 01-21-2003, 01:52 AM
  #35  
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Default Wire

Try inconel wire
the Thunderchief has spoken

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