Why Buy Eureka Cores?

Haven't hundreds of these airplanes already been built by hand cutting the cores?

Absolutely! It can certainly be well enough done by hand to give completely adequate results. I just want to give you a few points to ponder first.

1. EZs and Cozys are very labor intensive projects. Unfortunately, a great number of them are never completed due to the huge amount of labor involved. They sit in garages all over the world collecting dust.

Buying pre-cut cores is simply a way to reduce the amount of overall labor involved in the building process and make it that much more likely to eventually get off the ground.

How much labor?

If you cut cores by hand, here are a few things you will have to do:

    A. Either cut up your plans templates or make copies of them. Making copies presents its own challenges. These days it is fairly easy to find a place that can copy or print out large format drawings but it isn't easy to find a place that can do it with any kind of precision. How much error is too much? Personally, I like to keep error to a minimum, especially on the pattern.

    B. Glue your paper templates to some sort of stiff template material. Make sure you use the right kind of glue or the paper will possibly shrink or expand causing more error.

    C. Cut out your stiff templates being very careful not to mess them up. Make sure they are very smooth or your wire will catch. Oops, cut over the line a little? There's some more error.

    D. Build a hotwire bow and power unit. Not too hard to do but more work and expense nonetheless.

    E. Get some foam and a partner and do some test cuts. This may cost a block of foam depending on how much practice you need. The more you get the less likely you will be to mess up the cuts that count.

    F. Cut your foam blocks to size using straight templates. I use my CNC hotwire to do this and there's still a lot of work and time involved. I'm sure it's even more time consuming when you have to nail two straightedges on the foam for every cut.

    G. Glue your foam blocks together using popsicle sticks

    H. Precisely position your templates on the foam blocks and nail them in place. The position of the templates on the block is critical to get the sweep and twist correct. Don't screw it up!

    I. Get your partner and go to town. Make sure you get the speed and temp just right or you'll get either an undersized and cratered part or wire lag. Don't sneeze or allow the wire to catch or you'll get ruts in your part.

    J. Go back and add more templates to cut your conduits and aileron cutouts.

    K. Lightly sand off the angel hair.

    L. Use filler to fix any ruts and depressions.

    M. Viola! You are finally to the same point you would have been if you had ordered the cores from Eureka in the first place. If you made any big mistakes along the way and had to order more foam you may have spent the same amount of money as well.

If, like some builders, you decide to cut oversized cores and sand down to final shape with a long sanding block or try the hard shelling technique, add a whole bunch more labor to this.

2. CNC cutting allows for extremely tight dimensional tolerances and ensures the left wing is the same as the right and the same as was originally intended.

If you want to endeavor to cut your own cores then, by all means, go right ahead. I'm just offering an alternative