I'm doing a patch repair on a surfboard and want to set up a vacuum patch over the repair area only ie not a full bag over the whole board. I've looked at some sites on line and they recommend to only apply a partial vacuum so as not to damage the board. They show a setup where the vacuum pump is working against a controlled leak - tee piece in line and a small pipe clamp adjusted to get the vacuum needed - in my case 8 in hg. Trouble is my pump instructions say not to do this. Can anyone recommend the correct setup for this?
Thanks