I am getting ready to throw my first sandwich board into the bag (it isnt looking too great, EPS sure is different to work with!) and I know this subject has been discussed a lot but after searching the archives there is one point that I am a little hazy on: the use of a breather. I know many have said that bubble wrap works great but where do you put it? Around the whole of the board or just on one side (ie under or on top?). Also, with so many people just starting into vacuum bagging I am curious what bagging disposables people are using, trying anything different/ alternatives?
I use bubble wrap on top of the sandwich skin,wrap the whole board.
When you vac the laminate, I think some use no consumables, I use bread wrap release film and very light breather on laminate side, with breather also on other side of board. Always do a dry run and make sure you have even pressure throughout the bag.
Are you doing a sandwich lam like Bert? The breather is there to allow the evacuation of the air inside the bag by creating an open passage. If the bag seals itself off it will trap air. If you are doing a lam between the foam you could use some dry glass (6-10 oz.) as breather. If you need to get a good “pull” on an area thet will leach resin you could cover it with plastic then dry glass.
Always do a dry run and make sure you have even pressure throughout the bag
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This needs to be repeated 1000 times. I almost didn’t do a test run and it would have been a disaster. I went through 6 different brands of tape and made 3 completely different bags before I finally got one to seal. None of the tapes were able to stand up to the vacuum (It was so bad I though that my pump wasn’t working. I finally went to Uline (one of the nicest companies I’ve dealt with) and got some tube bagging, taped the ends, then attatched homemade pvc clamps (like Bert once upon a time used). I would have needed epoxy with 24 hour working time if I hadn’t done a test run first.