Bending plastic rod

[PHPaul]

I needed to put some fairly precise bends in some .06 Plastruct round stock.  

I've used various sources of heat including heat guns, soldering guns and even open flame, but avoiding distortion and scorching while getting accurate bends was always a challenge and I usually have to bend several pieces before I get one that's suitable.  Hot water works, but keeping it hot enough in my basement hobby area is a pain.

As I was laying it out it occurred to me that a drop of hot glue at the apex of the bend might put enough heat in the plastic to allow it to bend without stretching or distorting.  

At least for the small stuff, it worked great!  Just the right amount of heat, lasts long enough to work the plastic and peels right off after it cools.  If you need to adjust the bend, another drop will do the trick.

[NOBLNG]

Well that sounds like a brilliant solution Paul! The heat sources I’ve tried either don’t have the pin point accuracy that the hot glue would, or are way too hot. Thanks for the tip!?

[Bernard Kron]

Thanks for the tip. This might sound awfully basic, but what do you mean by hot glue?

[Mark]

Hot glue is those glue sticks that you put into a glue gun which heats them up.  There are smaller glue guns for the craft people, the regular size ones are used for other things.  

The hot glue for heating/bending styrene rod is a great idea, you will get consistent temperature every time unlike using matches or other heat sources.  The glue will peel right off once cooled.  I use hot glue to temporarily glue slightly warped resin bodies onto chassis, to pull everything back into shape.  Works great for that too, you can put the temporary assembly back in the box, then pull everything apart when you pick up the project again.

[Bernard Kron]

4 minutes ago, Mark said:

Hot glue is those glue sticks that you put into a glue gun which heats them up.  There are smaller glue guns for the craft people, the regular size ones are used for other things.  

The hot glue for heating/bending styrene rod is a great idea, you will get consistent temperature every time unlike using matches or other heat sources.  The glue will peel right off once cooled.  I use hot glue to temporarily glue slightly warped resin bodies onto chassis, to pull everything back into shape.  Works great for that too, you can put the temporary assembly back in the box, then pull everything apart when you pick up the project again.

Thanks for explanation. I'm not really into the crafts hobby world. I just looked it up on the 'net and I see what it is now. Fascinating that it's removable and yet firm enough to straighten a slghtly warped resin body. Sounds promising for mockups?

[Mark]

The hot glue temporary assembly on resin bodies doesn't straighten the body in and of itself, but it does let you pull the body into shape and assemble it in a corrected stance.  Some "mass produced" resin bodies (Jimmy Flintstone in particular) are pulled off of the mold before they have fully cured, and finish curing with the rocker panels spread further apart than they should be.  Pulling the body into the correct shape often corrects interior bucket and hood fit.  

Even when the body is straight to begin with, keeping it assembled correctly will keep it from going out of shape during storage.

[EngineerBob]

I use a cordless butane soldering iron (such as the one from Weller but Harbor Freight carries one also) that has an attachment to turn it into a pin-point heat gun for bending styrene rod. Allows you to precisely heat a very localized area. Like all heat sources, you have to learn how much is just the right amount of heat for the bend that you are making. 

[afx]

4 hours ago, Mark said:

I use hot glue to temporarily glue slightly warped resin bodies onto chassis, to pull everything back into shape.  Works great for that too, you can put the temporary assembly back in the box, then pull everything apart when you pick up the project again.

Great tip.

[Rick L]

That is a great tip. Be careful to test your hot glue first. There’s many varieties. Some are made to hold on extremely well and are a pain in the butt to remove.

[Rodent]

I am not suggesting that anyone go out and buy one of these simply to bend styrene rod with, but we have one and it works well for that purpose. My Thermapen says that the water coming out of the nozzle is around 187F.

[Straightliner59]

I have  Conair hair dryer that is hot enough to bend plastic. It took a little practice to keep from blowing stuff off the bench, though. No matter where I thought I was pointing it,  it would manage to find something to move!

[peteski]

On 2/3/2022 at 5:57 PM, Straightliner59 said:

I have  Conair hair dryer that is hot enough to bend plastic. It took a little practice to keep from blowing stuff off the bench, though. No matter where I thought I was pointing it,  it would manage to find something to move!

I assume that you lie it down on the bench?  If yes, just put it on some piece of rubber.  A properly positioned elastic works for me.  I also assume that one of those rubber disks made for opening tight glass jar lids would also do the trick.  A rubber glove would probably work too.

[Straightliner59]

3 hours ago, peteski said:

I assume that you lie it down on the bench?  If yes, just put it on some piece of rubber.  A properly positioned elastic works for me.  I also assume that one of those rubber disks made for opening tight glass jar lids would also do the trick.  A rubber glove would probably work too.

No, I hold it, and wave it across the plastic. That creates more uniform bends. I have a teardrop trailer, somewhere, around here, that I bent the top cord of using that method. I cut a balsa template, then heated and bent the strip around the template, pinning it, as it was curved. If I can find it, I'll take a few shots to better illustrate it.