Making stretched sprue
by Jim Baumann

This is a simple process that can yield enormous quantities of supremely fine modelmaking material-completely free!

Traditionally one would hold a piece of sprue over a candle and pull
apart slowly.
For rigging this has the disadvantage that it often results in uneven thickness and can contain small lumps. This is because as the sprue is stretched one side cools-and the other then stretches-this unevenness is reflected in the final result.

It is also important to use 'good' sprue.

I have for years been slowly melting down the runners and parts of a black moulded Airfix HMS Victory for standing rigging--and the brown plastic spars of a wrecked Revell Cutty Sark...
The raw material for stretched sprue does not have to be sprue-it can also be the actual plastic parts

When making stretched Sprue I recommend doing so in a room that is ventilated by a very gentle draft - ideally adjacent to workbench- the byproduct of smoke or smuts that can occur when heating styrene should be removed by the ventilating breeze-not the stretched sprue produced form the bench!!

My favourite method is to hold the sprue in my left hand-and the lighter in my right hand.

Light the sprue by holding the flame to the SIDE of the sprue piece flame

--allowing it to just catch light
 

Drop the lighter on the bench, change hands whilst blowing the flame out and dab the molten end of the sprue onto the far end of a piece of white smooth card( I steady the card on the bench using my left hand)

Initially for the first 2 inches( 50 mm) or so pull gently until the desired diameter is reached

Once the correct gauge has been reached( within a split second) pull away swiftly as far as your arm can reach
 

Stretched Sprue is free- so make as much as you can use in a given rigging session

It can be made thick or thin to choice