I've read several posts from people saying they use stretched sprue for making antenna wires. What exactly is stretched sprue and where can I get some? Right now I'm trying to use some tiny silver wire from the craft store and it's not working very well.
Thanks,
Hermon

Hi Hermon!

Stretched sprue is a bit of plastic sprue that has been heated on a candle flame. By pulling on the two ends of the sprue, the central part wich was heaten (not melted) becomes very thin.
Don't ask me how exactely to do as I never managed to do it right!

Jean-Luc

1. Take a section of sprue, a piece long enough that you will be comfortable holding the middle over a candle flame and clear of any lumps in the middle section.
2. Hold the centre, of the sprue, about 20-30mm over a candle flame (maybe more, but not in the flame), revolving it as you do.
3. The sprue will begin to melt and sag. (A bit of trial and error is called for the first couple of times)
4. Take the sprue away from the flame, and pull the ends apart..........dada............stretched sprue.

Note.
You can veary the thickness by waiting a second before pulling. Pull imeadiately and you will get very thin sprue, wait and get thicker. Wait to long and it will cool and you wont be able to stretch it.

Just remember to take the sprue away from the flame. This can be achieved by using a light bulb, but how ever you do it be careful, heat and plastic don't really mix. If using a candle use a birthday cake candle and make sure it's not going to fall over. I have a chemistry set meths burner.
HTH
Mal

Hi I have had some success doing this as Mal describes. I sat down one night and collected all my scrap sprue and kept going until I had an envelope full of various thicknesses. Once fitted to the model, sprue can then be tightened up by bringing a heated screw driver or a freshly extinguished match head close to , but not touching, the sprue. The residual heat causes the sprue to shrink a little and voila, nice and tight.

Hi,
I've dropped this technique a while ago as I never managed to get the proper thickness I needed

I turned toward piano string and found it perfectly works without any effort (except cutting the desired length )

HTH
olivier

If you wan't really thin wire (for 1/72) , I highly recommend using fly fishing line. Since it's flexible, the wire stays stretched.

I've used it for rigging biplanes. For some tips, see here

Good luck!

Ok, I spent 3 hours last night trying to "stretch some sprue."
I have come to the conclusion that all of you who use this method for making antenna wires are either
A. Mentally insane
B. Have been overcome by CA glue fumes
C. Just playing a joke on me

Is this one of those jokes like when you tell someone to go get you a "left handed" screwdriver out of your tool box? :-)
I have decided that if I have to use stretched sprue to make my antenna wires then from now on all of my planes will not be equiped with radios.

PolarBear, thanks for your link. Great plane by the way. I believe your method would probably suit me best. I'm off now to buy myself some fly fishing line and some tiny drill bits.

Thanks guys,
Hermon

Herman,

It is not a joke.
Get a straight length of sprue about four inches long.
Hold it in one hand a slowly rotate it about an inch and a half over a flame. As soon as the free end, the end you are not holding on to, starts to bend toward the floor, remove the sprue from the heat and pull the ends apart. If you wait a few seconds for it to cool and then stretch you will get thicker stretched sprue. If you stretch it fast while it is still really hot you can get it as thin as a hair...
Keep on trying. More art than science.
:-H

Shaun

Herman:

Well, let me give it a try. As Shaun has said, this
isn't one of those, "left handed screw driver" kind
of jokes. It does work. Unfortunately, you're are not
being shown this technique by a modeler standing
right in front of you. What the others have told you
is correct. However, I'd like to go into a little more
detail about it toward the end of the process.

I have both ends of the sprue in my finger tips at
all times. And I roll the sprue in my fingers over the
flame back and forth. How long to leave it over the
flame before you start stretching is critical, and you'll
only learn that from trial and error. But for me, the plastic is really soft, almost ready to burst into flames.

At that point I start stretching the sprue as I pull each
arm outward away from my body. Besure to pull with equal steady slow pressure in both arms/hands.
The sprue will let you know when not to pull any further
as it will start to resist. You will feel this resistance
as you slowly pull away from your body. Usually, when
I get to that point, my arms are as far away, each in
the opposite direction as I can get them. Don't give
up, you can learn to do this. Good luck,

Hi Hermon

Sorry I catched this post a little late
Although several good explanations were already given, let my add my 2 cents:
In a graphic way



I drew this last year to explain to one of our Warships Members how to do it... Give it a (safe) try

Also another tip:
Depending of how fast you stretch it the thinner you'll get the streched sprue.
Faster=Thinner
Slow=Thicker

;)

Skipper

I seem to recall something about a picture and a thousand words.

Thanks Skipper.

Shaun

Hi Hermon,
Why dont you give "invisible thread" a try.
No,,its not like a left handed screwdriver/tartan paint etc.
Have a look at Holdfasts online build of the Tamiya Spitfire.
Near the end,,page 13 or thereabouts,are some photos of exactly how its done.

Lots easier than stretching sprue,which is an art in itself

Sorry, I should have said, I never use stretched sprue, it's far to delecate
Mal

Well........I tried "stretching my sprue" again.........
Yeah, that didn't sound right did it?
It ain't for me.
I went out and bought myself a tiny drill bit and some fly fishing line. After about 20 minutes of drilling and stringing the line I now have a completed radio antenna on my P-40. Used a black sharpie marker to color it and it looks awsome even if I do say so myself.
For all of you who have mastered the art of sprue stretching I salute you for you are more patient than I am.




Thanks everyone,
Hermon