RE: Cutting a 40+ inch foam combat wing  
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RE: Cutting a 40+ inch foam combat wing - 6/8/2006 8:51:53 PM   
Bipe Flyer



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Status: offline 		I could build one for about half of what I paid, now that I know how to do it. It was a very rewarding project. Watching the first wing core come out was like the first flight with a new plane. I'm very tempted to build a CNC router, but I probably wouldn't get much use from it as I almost never cut ribs. Someday...

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RE: Cutting a 40+ inch foam combat wing - 6/8/2006 8:53:04 PM   
flyswatter



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From: St. Simons Island, GA, USA
Status: offline 		pt:

So alright already! How about quit talking and start cutting (or is it burning, or melting?) us some wings!! btw, I have some old Lionel transformers that might work as a power source and, also, I have a 120vac to 12vdc power supply I use for powering the old DC Astroflight chargers. Can you, do you, want to use any of this stuff??


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RE: Cutting a 40+ inch foam combat wing - 6/9/2006 2:22:54 AM   
KidEpoxy



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From: San Antonio, TX, USA
Status: offline 		CP could probaly make a mint shipping 12packs of DNU wings to just us 1/2A'ers
CP's "As Is" DNU parts.... Warranty void if package opened.

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RE: Cutting a 40+ inch foam combat wing - 6/9/2006 3:38:35 AM   
vicman



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Status: offline 		The train transformer is perfecto!

While we have made the shift to CNC. I have built 80% of a machine that will hold a 4'x4'X6' block. Where does the time go. I will finish it one day and give the combat kit suppliers and big wing guys a run for thier money...one day.


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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 4:05:23 AM   
ptulmer



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Status: offline 		The bow is built and I played with it today using stainless fishing leader. The dimmer switch is a little difficult to set. I'm thinking about making some smaller bows to go along with this big one. What do you guys think of this? <link> I'm not sure how fine the resolution is on a variac and don't want to throw money away. I'd like to make several bow sizes, record their voltages and use it with all of them. Maybe it's time for DC?

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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 4:14:09 AM   
Bipe Flyer



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This is a lot cheaper. http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=43060

Are you using a transformer?

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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 4:29:40 AM   
ptulmer



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Status: offline 		No, straight 110. It works, but you've got about 1/8" on the dial from "starting to heat" to "red-hot wire". Maybe a train transformer would make the resolution of the leviton dimmer a little better? I'd like to set a power box up and attach whichever bow I need at the moment.

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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 4:41:33 AM   
KidEpoxy



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Status: offline 		PT: have you tried it with a longer wire/ more resistance?
Maybe throw a 40w or 75w lightbulb inline (serial) to get the ohms up... dunno, cheap to try and it might just help.

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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 4:50:09 AM   
ptulmer



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Status: offline 		KE, the bright side to that idea (sorry for the pun) is you'll know when the power is on.

What amperage do you guys think a transformer should be? Allelectronics has a decent variety of transformers like this one.

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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 5:21:48 AM   
soarrich



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Status: online 		ptulmer
That looks like the variac I have except mine is black and has no meter. I cut using about 18~20 volts with mine on a 30 inch bow.


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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 5:52:08 AM   
Bipe Flyer



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Status: offline 		I'd feel really uncomfortable using 110 without a transformer. Mine is 18VAC 60VA, so that's about 3.3A.

All Electronics also has a 3A version of the one you were looking at.

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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 6:25:49 AM   
KidEpoxy



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Status: offline 		"I'd feel really uncomfortable using 110 without a transformer"

Maybe he could use a florecent ballast to transformer it to 400-600v

Overboard on safety, he could use the lightbulb on the hot, then to the bow, and then to a independant ground-run 'nuetral'(fault). The hot is dropped by the bulb then it could go to the bow with a current limit... shorting on the return wire wont up the amps. Looking at both directions of a short, from the bulb the current is limited by the voltage drop dimmer and the current cap bulb. From the return side, it is a ground-run nuetral, so shorting to ground from ground is ... well, it actually isnt.

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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 3:31:08 PM   
ptulmer



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Status: offline 		Bipe, I'll take a picture this afternoon. There's no real danger from the voltage. Everything exposed is on the low side of the dimmer. Actually, the exposed parts are only down there at the hot part, and I ain't gonna touch that anyway!
I'm pretty amazed at how little power is needed to do the work! Thankfully, by careful adjustment of the dimmer, I can go ahead and cut some foam! Wind and rain have conspired against me for the past couple of days, so I haven't picked any foam up. Hopefully, that will change today... if I can get away from "her". Oh yeah, gotta make some templates, too!
I gotta think of a good way to strip the big sheets down. Aside from CP's two-man table saw method, what do you guys do with the big sheets?

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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 4:09:55 PM   
ZoomZoom-RCU



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Status: offline 		Cool Ptulmer. Sounds like your having fun, show some pics of what yer workin on! I'm experimenting at the other end of the spectrum, I've cut many 1/2a size wings with my 23" home made foam bow, but am currently finishing up an 80" Fokker DVIII with the wing made from a variation of the same theme. It was all cut out of blue foam in .....can you guess..... 23 inch sections. Then all assembled and glued to the central spar system. Of course, blue foam being a tad on the heavier side of the foam stock, I had to get some lightening done to each section. To accomplish this I lightened each of them by heating various sizes of metal pipe in a stove and then inserting them longitudinally through each of the sections at different spacings, thereby reducing the weight significantly. It also provided nice shafts in the wing for me to run servo/control wires through. Never ceases to amaze me what you can do with this stuff. Good Luck!

ZZ.

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RE: Cutting a 40+ inch foam combat wing - 6/14/2006 7:51:42 PM   
Bipe Flyer



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I've accidentally touched my wire (Foam cutting wire, that is.) - just a little burn. If the wire is between the dimmer and ground it should be relatively safe, but if the wire is between the dimmer and hot and you touched it while grounded... I'd at least plug it into a GFI. Anyway, you probably don't want Mr. Safety nagging you.

An electric carving knife works well for cutting down large sheets. I'd get in trouble if I used ours, so I use a large Olfa box cutter. I just trim the sheet to 42", the size of my foam cutter, and then use the chop function to make smaller blocks.

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RE: Cutting a 40+ inch foam combat wing - 6/15/2006 12:31:55 AM   
combatpigg



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Status: offline 		Patrick, if the dimmer is twitchy, you don't have enough stainless cutting wire in the circuit. My bow is about 3 fett long, so there is about 6 feet of cutting wire in the circuit.

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RE: Cutting a 40+ inch foam combat wing - 6/15/2006 4:38:27 AM   
ptulmer



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Status: offline 		My house is built below the 100 year flood plain. (which doesn't mean it floods every 100 years) So all my "basement" outlets are GFI. That's why I don't sweat it too much.

CP, that would be a funny looking 12