Help bending plastic.

You're using the wrong material. If you need a 90 degree bend in plastic make a 90 degree joint instead. Cut the pieces the right length and cement.

Instead of using styrene consider using aluminum or brass sheet. Precision is greater and it will hold its shape. Heating plastic to make such bends is an exercise in futility.

gawga

I'm using .04" styrene plastic cut into a strip .348" wide.  I need to bend it in a series of 90* angles.  Is running boiling hot water over it the only possible way?  I am looking for alternatives as it is too brittle to bend cold. 

Also, the bends need to be precise as possible, so what is the rule of thumb of bending radius on a 90* bend with plastic of this thickness?

Thanks,

Gary

Please clarify.   Are you seeking to make a sharp 90 degree bend or a radius bend of 90 degrees?

The sharp 90 degree bend - go with Hawkeye's suggestion.  

A radius turn,  make a jig with a piece of dowel or pipe of the desired radius.  Add some pins to hold the piece of plastic in place on the jig.    Instead of boiling water heat the plastic in the oven at 180.   Take the plastic as is sags and place in the jig.   Pin the plastic along the dowel to hold it close to the desired radius.

The application is to represent an iron band wrought by a blacksmith on my model - hence the radiused corners.  I have had a difficult trying to bend thinner brass than .04 and I wanted to use plastic as I thought it would be more maliable.  I used the boiling water trick and was 50% pleased.  I will reconsider the oven at 180* if I can find a time when the wife is out of the house ;-)

You may want to experiment with a simple jig to bend the plastic while using a hair dryer as posted above with a dowel as a guide. I used this method for making a screen frame for an armored car I'm working on. 

For Gawga, please fill me in briefly (or links) about the boiling water trick and the 180* oven to alter polystyrene shapes. My needs: I'm starting  a Renwal trident boat w/ interior. I want the unglued seam of the hull halves in as close an alignment as is practical (when closed of course). When I rubber band the two empty hulls together they fit well  after some adjustment. Do you think I can heat them slightly so they'll stay that way after cooling and unbanding?  Possibly not, but inquiring minds want to know.  Thanks dgb