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General control line discussion => Open Forum => Topic started by: Paul Taylor on May 31, 2008, 07:52:54 AM
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I got some foam awhile back and found an old battery charger. I would like to try my had at cutting foam wings the easy way using a bow and .012 flying line.
I would like to find something at homedepot or lowes for making templates or maybe another easy source.
Any suggestions?
Thanks
Paul H^^
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There is all kinds of stuff for making templates. Starting with plywood or even what is called hard board. Both need edges smoothed and sanded with either CA or epoxy. Then there is the thin Aluminum sheets. Not much else I can think of or would even consider using. Most of my templates are made of plywood from the scrap box in the shop. Make sure the edges are super smooth or they will catch the wire as you go. Of course experience is the big teacher. Have fun, DOC Holliday
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I make mine from post form plastic laminate (Formica) counter top covering. I use to install a lot of it back in the day. You have to get what they call post form not pre form as post form is thicker and seems to be harder. It's usually in the back by the counter top displays. If you can find a custom counter top shop they my just give you some small scraps their not good for anything else.
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The big problem with using stainless steel wire for foam cutting is that it expands quite a lot when heated. That makes it difficult to adjust and maintain the wire tension during cutting. During a cut, the foam material tends to cool the hot wire, making it shorter (tighter). Increasing the Variac voltage (and current) restores the wire temperature, but then the wire sags. Tjhe result is an uneven cut. Foam cutter rigs having some kind of spring to maintain tension helps a little, but steel wire is still difficult to control.
The recommended wire is called "Nichrome" and is available through some of the big mail-order hardware (McMaster-Carr?) stores.
I was in the kit business for a while, and I experimented with foam wire cuters quite a lot.
Floyd in OR
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Small quantities of Nichrome wire is/are? available from Sig.
http://www.sigmfg.com/cgi-bin/dpsmart.exe/MainMenuFV4.html?E+Sig (http://www.sigmfg.com/cgi-bin/dpsmart.exe/MainMenuFV4.html?E+Sig)
Seems that link opens the main page. I guess you will have to do a search for "nichrome"
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Hi guys,
I had a friend who used aluminum duct tape from Home Depot type stores to cover the edges of 1/16" - 3/32" plywood templates. This gives a smoother edge to give a better cut than plywood alone and it also prevents the wire from burning into the template if the cutter hesitates during the cut.
I find that .012 flying wire works just fine especially if you have a Variac adjustable transformer. I tried nichrome wire, repeatedly, years ago and I never got as consistent a result as I did with flying line. I used nichrome wire in several guages and I had it break during cuts and it seemed to have "hot spots" in the wire that left a low spot on the core. I know others have used it ok but I was never really happy with it. I guess it is one of those "results may vary" kind of things.
Paul I wish you the best of luck.
Pat Robinson
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When I got on the foam kick, I made templates from 1/8" 5-ply birch plywood. I sanded the edges smooth, and soaked them with thin CA, then sanded them smooth again. After a few treat and sand cycles the edges were glassy smooth. After that the next problem is getting the temperature right, and moving the bow at a consistent even speed to get a clean cut without over/under cutting the foam. I did 3 sets of cores before I got one good enough to use. I ended up with 3 good sets of cores, and a couple so-so sets. For the effort I think it's easier and lighter to just build wood wings.
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Galvanized sheet metal duct material. Use scrap from a furnace job or buy new at Tony's (Home Depot).
Unlike other materials suggested, the hot wire doesn't hurt it.
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I have to chime in on using formica. It works at least as easy as plywood with hand tools, is heat resistant (much more so than plywood) and can be picked up as scrap if you know anyone that does cabnet work. I have cut hundreds of foam wings for combat models using the same templates at least dozens of times. As far as flying line as cutting wire just make sure there is some spring in your bow. I actually just use a 1/4" hardwood dowel and cut a bit slower than some other folks with good results. I like a very lightweight bow as I am usually cutting alone.
Bob Furr
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Yea Bob I've used alot of Formica for templates other than foam cutting. I also have some very old Formica thats almost 1/8" thick made in the 60s or early 70s. I have never had a problem with melting it with the cutting wire and it will sand to a really smooth edge. My Dad and me used to install it back in the 70s wish I would have save more scraps from then. There are some very funny stories of our escapades into Formica gluing.
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Paul,
The best suggestion I can give is to forget about messing it with yourself and give Crist Rigotti a call.