Coring foam wings?

How do you cut the cores in foam wings? I've found lots of web pages that describe how to cut the outside of the wing and lots of stuff on sheeting the wing but I haven't found anything that tells how to cut the core. It seems to me that this is the second most important part of the process.

Well..here is how I do it.

First, I create a second set of templates with the correct coring. If you use one set, they get kind of flimsey. I use formica.

The general process is this then; First, drop a hod rod down through the wing for each core. Then, detach the wire from one end of the hotwire bow and feed it through the hole. (templates are already mounted to ends of panel.) Reattach the wire and with two people hold the wire centered in the starter hole as the wire heats up. Then calling the wire location to the other person, run the wire around the inside of the template. Repaeat for each core.

For the starter hole, I use two steel 90 degree shelf brackets about 4inchs on a side, clamped to a door or wall one over the other. They have a 1/4" hole in each aligned so a 1/4" rod will drop down through them both. Shim and align them so that the rod will go down exactly parallel to the wall, at 1/2 of the total foam thickness used for the wings. mark the floor where the rod touches.

Place the wing in its shucks and support against the wall under the brackets. Make sure the point of exit at the lower end is aligned with the mark on the floor and the entry point is under the bracket holes.

Heat the pointed rod end with a torch until dull red at the end.

Quickly drop the rod down through the two brackets--it will drop through the wing by gravity. QUICKLY remove it as soon as it hits the floor.

That is the starter hole. Its the most difficult to get set up--but once the brackets are aligned, it goes fast.

Practice on a few scrap pieces to get it working first.

After that, just stringing and unstringing the wire from the bow is the worst part for me.

1/4-3/8 wall is what I use with .9lb foam. and spars to suit.

Hope this helps. THere are several online foam cutting sites that have this illustrated but I dont have them marked.

In response to your question, two of the members of the Omaha Orbiting Eagles CL Model Club, Bob Furr, and Ed Prohaska, put together an excellent video on foam wings. Bob has designed a rather unique and more workable cutter, and demonstrates from foam selection to coring the wings. I have never made a foam wing, but after viewing this video I think I could do it. I know I have all the items to make his system on hand. (Household items) Don't quote me, but I think the video is only about $10. If you are interested, let me know cuz our next meeting is next Wednesday 4/21. This is about a two hour video, light heartedly done, but a wealth of information.

Okay... with that lead in... chuckling. Good-To-Go Models produced a video on cutting your own foam wings. As Shel said it covers the process right up through coring wings and making the special templates to do that. I have copies of the video as it was produced in my shop. If you can pick up the video in Omaha it is $10 but with postage and running to the post office it is $15 anywhere in the USA. I will take a check but ship same day if you send a money order. I am not a business so I dont take credit cards.

Bob Furr
15872 Farnam Street
Omaha, NE 68118