Using heat does the trick, but DON'T BURN YOURSELF. Keep the styrene rod far enough away from your heat source, and as soon as you feel the styrene "getting loose" ( before it shrivels up), bend it around a form to get the angles uniform, then let it cool down on it's own. Years ago, I used a lit cigarette to heat the styrene, but I don't smoke any more.....wished I never had started! Anyway, using that method, this is an example of uniform bends to make headers. These are 1/32 scale, so .060 in diameter.