Vacuum bagging parts with the Space bag has been a mixed scene so far.  It is a wonderful concept, but the bags have been failing.  I started with the 3’ x 4’ jumbo bags.  I am bagging the dome triangles for the lunar lander top.  They are ply/core/ply sandwich parts. Recall that the spacebags let me run the vacuum for only a few minutes, not the usual 6 to 10 hours. The first jumbo bag kept the vacuum for 3 days until it failed.  The second jumbo lasted an hour and the third was good for about 10 minutes.  A smaller XXL bag lasted 2 days, but as in this picture, on a second attempt, the bag would not hold a vacuum.  I tested the closable seams and they were fine.

I spoke to SpaceBag and they will send replacement bags.  They did say the bags should be airtight when you get them and good for several uses with no problems.  I guess I will need to fill up the bathtub to see where the leaks are.  I will do a dry run on every bag in the future to test it first.  Notice the duct tape on the sharp edges to protect the bag.