On Thu, 2 May 2019 15:02:46 -0700, Bob La Londe
wrote:

Since its new to me I figured I'd just use springs from my junk
collection and measure the force of the springs. Then order springs to
suit after that. I set up a little jig a while back to measure travel
of springs under weight on a platform for calculating spring force. I
was doing some airgun modifications. Its a pretty simple tool and easy
to make.

I never would have thought to look for "mold springs" or "square mold
springs." Thanks.

Since there is some heat in when injecting thermo plastics I was
concerned about spring life.

Rotational molds often use springs to even out the pressure of the
clamps holding the lid closed. They survive many trips through a
~400 degree Fahrenheit oven... Do eventually need replacing. And we
used both round and square cross section springs.

Used auto valve springs my son got for me at a junk yard for the one
mold I made.
http://alt-config.net/msbh/firstmold.html
--
William