Bending styrene tube

[NOBLNG]

I bent up some 3/32” plastruct tubing for a roll cage with some soft wire shoved inside. It bends beautifully, but the moment I touched the bend with some Tamiya quick set, the styrene split. I eventually used CA for my cage which does not cause a problem. But then I tried another test. After bending I just quickly passed it over the flame of a butane lighter. The flame took all the tension out of the styrene. The middle bend has also had the quickset applied…but no cracking at all. I imagine it would work for solid rod also if it is prone to cracking.

Edited June 4, 2022 by NOBLNG

[Mike C.]

Where is a good place to get this soft wire and what sizes are we talking here?

[NOBLNG]

1 hour ago, Mike C. said:

Where is a good place to get this soft wire and what sizes are we talking here?

It is actually T-bar ceiling hanging wire that measures .049” diameter. It goes in fairly snug….I have to polish it a bit sometimes to get a 6” length to slid in. I also got some 18-2 bell wire from lowes that fits a bit loose (.040” diameter). It’s copper, so not near as stiff as the hanging wire, but it does keep the tube from collapsing.

Edited May 18, 2022 by NOBLNG

[Mike C.]

8 minutes ago, NOBLNG said:

It is actually T-bar ceiling hanging wire that measures .049” diameter. It goes in fairly snug….I have to polish it a bit sometimes to get a 6” length to slid in. I also got some 18-2 bell wire from lowes that fits a bit loose (.040” diameter). It’s copper, so not near as stiff as the hanging wire, but it does keep the tube from collapsing.

Good idea. I have many tube bumpers and roll cages I would like to build but I have the same problem with the tubing collapsing when  I heat it up to bend it.

[NOBLNG]

2 hours ago, Mike C. said:

Good idea. I have many tube bumpers and roll cages I would like to build but I have the same problem with the tubing collapsing when  I heat it up to bend it.

No need to heat the tube with wire inside (unless you want to use a solvent glue on it).  I have used solid rod for exhaust pipes. It can be cold bent too, but is kind of hit and miss for getting a perfect angle. I like the tube and rod idea because the angles can be adjusted minutely and it holds its shape. 

Edited May 18, 2022 by NOBLNG

[Bugatti Fan]

Any material, metal or plastic suffers stress when formed cold in any way.  As polystyrene becomes more malleable when heated as it is a thermosetting plastic, another method is dipping in very hot water to soften it or placing it on an oil filled radiator. It is a bit trial and error until you get a feel for how the material will respond.

[afx]

I use solid rod in lieu of tubing for my custom roll cages and headers.  Liquid cement can cause the bends to fail if there is stress in the transition. 

Sprue glue (styrene bits + liquid glue) works nicely as weld at the joints. 

[Plowboy]

1 hour ago, afx said:

I use solid rod in lieu of tubing for my custom roll cages and headers.  Liquid cement can cause the bends to fail if there is stress in the transition. 

Sprue glue (styrene bits + liquid glue) works nicely as weld at the joints. 

I prefer to use solid rod also. It takes an extreme bend for it to crack.