hot wire help  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       

All Forums >> RC Airplanes >> Composites Fabrication And Repair >> hot wire help
Page: [1]

Login
Message << Older Topic   Newer Topic >>
hot wire help - 10/25/2004 10:00:06 PM   
ssphoenix23


 

Posts: 7
Joined: 4/27/2004
From: glenwood, CO, USA
Status: offline 		Keep braking the hot wire. Not sure why but just for simple cut while cutting on long foam (36" wing), the wire breaks quite easly and often. I am using the blue foam and the wire came with my feather cut bow from ast. I've tried several settings for power from 7 to 16V.

Help would be greatly appreciated.

Thanks
       Post #: 1

RE: hot wire help - 10/26/2004 12:27:52 AM   
crash_expert



Posts: 124
Joined: 3/16/2004
From: The Great NW, AK, USA
Status: offline 		As to your wire breaking I can only think of two possible things.

1. Wire temp is to hot.
2. Pulling to hard.

Trying lowering your temp. The perfect temp comes when you finish your cut take a look at the core. You should see a cotton candy or cob web look to the foam pieces. Also let the wire do the cutting don't force it through the cut. What are you using as rib guides? I use 1/8 ply and burnish the sides so that I have a nice smooth surface for the wire to pass over with out getting hung up on anything.

Also if this is your first time cutting foam, get your self a couple of 4x8 sheets of pink foam from the hardware store and practice, practice, practice. You will learn hand placement and technique and how fast the bow should be traveling.

Good Luck and trust me it is addicting. Next thing you know you will be cutting turtle decks and such.

_____________________________

Good Judgment Comes From Experience. Unfortunately, The Experience Usually Comes From Bad Judgment.

(in reply to ssphoenix23)
       Post #: 2

RE: hot wire help - 10/27/2004 2:27:26 AM   
ssphoenix23


 

Posts: 7
Joined: 4/27/2004
From: glenwood, CO, USA
Status: offline 		someone mentioned that safty aircraft wire works well. I just happen to have some and workes very well. I thought between 9 and 12V would be a perfect power for the feathercut. The safty wire is awsome.

I will do some more testing but so far I am pleased with the result.

Thanks

(in reply to ssphoenix23)
       Post #: 3

RE: hot wire help - 10/27/2004 7:44:15 AM   
AmirN


 

Posts: 66
Joined: 4/18/2002
From: Las Vegas, NV, USA
Status: offline 		I've cut upwards of 120 cores, from small, skinny panels to 30" cords and nearly 60" span panels. The Feather Cut wire is sensitive to heat and not all that strong in tension. Tears too often, especially with the longer bows. I switched to Inchonel and it's stronger and tolerates heat ranges far better. Very predictable and precise. Haven't had one tear yet. There is a heat range along which you can get a great cut with all the angel hair, but you can control the speed of the cut while maintaining the same quality. Inchonel is very good at this. It's working great for me......The Feather Cut wire gets more difficult to work with as the bow gets longer too. I get mine from CST. It's been very good and solid even on a 70" bow, which has pretty good tension on it.....I've cut 1 lbs. foam, pink foam, Spyder foam, etc....Very happy with Inchonel :-)

Have fun,
Amir

(in reply to ssphoenix23)
       Post #: 4

RE: hot wire help - 10/29/2004 2:37:24 PM   
nIgHthAwK17



Posts: 71
Joined: 4/28/2002
From: Starkville, MS, USA
Status: offline 		After switching to tungsten wire (like whats in incandescent light bulbs), I haven't had any other problems. Not to mention it doesn't take nearly as much voltage to achieve cutting temperature, so you can make a really long bow! What is also convenient to tungsten wire is that it is 0.003" in diameter, so the kerf of the wire is almost nonexistant.

-CG


_____________________________

-----------------------
Ad Astra Per Aspera

(in reply to ssphoenix23)
       Post #: 5

RE: hot wire help - 10/30/2004 9:16:22 AM   
patternwannabee


 

Posts: 243
Joined: 10/8/2002
From: Mars, PA, USA
Status: offline 		Nighthawk,

Where can you get tungsten wire?

(in reply to nIgHthAwK17)
       Post #: 6

RE: hot wire help - 11/1/2004 2:02:14 PM   
nIgHthAwK17



Posts: 71
Joined: 4/28/2002
From: Starkville, MS, USA
Status: offline 		From me, actually...

How much wire do you require? Being that I have recently been blessed with a large amount of tungsten wire, I'm trying to come up with a fair pricing system to "distribute the wealth," if you know what I mean.


_____________________________

-----------------------
Ad Astra Per Aspera

(in reply to patternwannabee)
       Post #: 7

RE: hot wire help - 11/1/2004 6:57:45 PM   
chall



Posts: 157
Joined: 12/13/2002
From: Raleigh, NC, USA
Status: offline 		Hey, I'd be interested in the tungsten wire too.

I've also seen nichrome wire at $3.95 for 5-feet from RCM mag's website (http://www.rcmmagazine.com).

Does anyone know how the nichrome wire holds up?

(in reply to nIgHthAwK17)
       Post #: 8

RE: hot wire help - 11/1/2004 7:30:01 PM   
Jim Branaum


 

Posts: 1669
Joined: 10/22/2002
From: Fair Oaks Ranch, TX, USA
Status: offline 		My working buddy just picked up a FeatherCut system with TWO bows but NO instructions. When I figure out how to assemble the bows, I guess I will need enough for the two larger bows. Got any ideas I can use? PM me with a cost of the wire please.

TIA

_____________________________

Jim Branaum AMA 1428

(in reply to nIgHthAwK17)
       Post #: 9

RE: hot wire help - 11/4/2004 8:47:16 PM   
genek



Posts: 36
Joined: 6/30/2002
From: AZ
Status: offline 		Hi guys, I am trying to cut foam for the first time...need help. My cutter is home made, .020" wire from a hair dryer , wood bow, wire on spring tension, and 115v AC dimmer switch.
On a low setting I can get the wire to change colors, red/orange hot if needed. I tried different settings, the wire is taught and straight, but my cuts are concave {below the shape of my Masonite templates}. Can someone tell me what I am doing wrong? Thanks, Gene

(in reply to Jim Branaum)
       Post #: 10

RE: hot wire help - 11/4/2004 8:55:26 PM   
chall



Posts: 157
Joined: 12/13/2002
From: Raleigh, NC, USA
Status: offline 		I haven't done any of this yet, but from what I've read if you don't pull the bow evenly (i.e. both ends of the bow reach the end of the template at the same time) you'll get concavity.

One book I read suggested you place numbers like a clock on each template and get a helper to take one end of the bow and call them out as his end of the bow reaches each one.

Another book suggested you hold the bow in middle and position the work so you pull it towards you.

Both books say it takes a little while to get the hang of it.

How does the blow dryer wire work?

(in reply to genek)
       Post #: 11

RE: hot wire help - 11/4/2004 10:44:28 PM   
Scott Smith



Posts: 281
Joined: 10/29/2002
From: Agawam, MA, USA
Status: offline 		As for making sure the wire enters and exits at the same time, just set up some pulleys and a drop bar. The attached picture should explain. The last foam I cut I suspended the bow from a single point at the center and that seemed to work better.

The line that pulls the long side attaches to the tip of the drop bar. The other line will attach somewhere closer to the pivot point depending on the taper. A little trial and error is needed before actually cutting the foam.

BTW...I use .020 aircraft ss safety wire

Attachments
Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize


< Message edited by Scott Smith -- 11/4/2004 10:48:43 PM >

(in reply to chall)
       Post #: 12

RE: hot wire help - 11/5/2004 3:25:24 PM   
chall



Posts: 157
Joined: 12/13/2002
From: Raleigh, NC, USA
Status: offline 		Scott, I don't quite follow your explanation. Wouldn't the "short" side finish cutting before the "long" side?

And when you say experimentation, does that mean the weights as well? Or can you always use the same weights with the same foam density?

(in reply to Scott Smith)
       Post #: 13

RE: hot wire help - 11/5/2004 3:36:38 PM   
patternwannabee


 

Posts: 243
Joined: 10/8/2002
From: Mars, PA, USA
Status: offline 		genek,

Is the surface of your cutting table flat? How about your foam blank? Any curves in either will reproduce faithfully in your foam core.

When you're sheeting the wing, if you can use the same surface in the same location/orientation you used for cutting, you'll minimize the concavity.

Or, you can make sure all surfaces are flat.

As to wire temperature, red or orange hot is way too hot (assuming you're using 1# white eps). If you have a setup like Scott Smith, slowly turn the dimmer switch until it barely starts cutting and leave it there and enjoy the show.

(in reply to Scott Smith)
       Post #: 14

RE: hot wire help - 11/5/2004 3:51:15 PM   
patternwannabee


 

Posts: 243
Joined: 10/8/2002
From: Mars, PA, USA
Status: offline 		Chall,

A swing arm foam cutter has the ability to pull two ends of the wire at different speeds. You would attach the pull lines at different locations on the pivoting arm. Exactly where you attach each pull line will determine how much taper results. The one attached further from the pivot pulls faster. This would be for the root of the wing for instance. I suppose, given a taper, you could calculate where the attachment points should go, but experimenting is much easier.

(in reply to patternwannabee)
       Post #: 15

RE: hot wire help - 11/5/2004 5:46:03 PM   
yankee samurai


 

Posts: 129
Joined: 5/14/2003
From: Blackfoot, ID, USA
Status: offline 		Check this web site. www.tekoa.com

_____________________________

Randy Shiosaki

(in reply to patternwannabee)