Trying to figure out how to keep the bag to stay tight all the way through the infusion process. there’s absolutely no leaks before we start infusing the resin. But as soon as we open up the resin inlet line the inlet side/area of the bag loosens up and it really never get a tight until the resin starts to gel. Anyone have this issue or does anyone know how to fix this issue. I’m finding small pitting on the surface and only on the inlet side so i’m guessing g it’s happening from the bag being loose on that side.

My technique varies from part to part, based on what I am trying to achieve and the actual geometry of the part. 

For the most part I agree with Mark and I don't like to restrict the resin inlet, it does have a tendency to cause issues. That said, it depends on the part and the layup - some parts do really benefit from slightly restricting the feed line. So it is virtually impossible for me to say "do X or dont do Y" and it will solve all your problems. 

I suggest trying a part like you have been doing, as it sounds like you are nearly there, but try clamping off the vacuum line once everything is completely wet out and leave the resin feed open for a minute or two. Most of this excess resin will remain in the flow media, so the final part will only be a few grams heavier, but it can make all the difference for that surface porosity.

Ok will try that on the next one. We did lock off vacuum line and left inlet open for like a minute or two but maybe will go a little longer. We also switch over to using MTI hose for our vacuum/ exit line. And advice for that product if you have used it before?