With 300%+ elongation for Bagging Film, are pleats needed for CF parts with modest (limited) depth?

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With 300%+ elongation for Bagging Film, are pleats needed for CF parts with modest (limited) depth?

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John Hansen	J John Hansen posted 5 Years Ago HOT Topic Details
J Group: Forum Members Posts: 42, Visits: 232	I read published specs for bagging film indicating 300% to 450% elongation. When I study the tutorial videos on resin infusion, I see everyone using pleats. Is it really necessary to add pleats when the film will very likely stretch as much or more than the depth of the female cavity in the mold (mould)? I can easily imagine that a car bonnet would not require any more than 150% elongation. Could that be done without pleats? A Lifelong Learner
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Hanaldo	Hanaldo posted 5 Years Ago Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	No, it's not ideal. The bag stretches under full vacuum. When you infuse and the resin fills the cavity, the bag is no longer under full vacuum. This means the bag slacks back off, and there is more space for resin to flow into, creating a more resin rich part. In practice, it might not end up extremely resin rich and is probably acceptable for a lot of people, which is why you will see videos of people doing it. But for the sake of a few pleats, why not get the actual performance benefits of infusion?
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oekmont	oekmont posted 5 Years Ago HOT Post Details
Group: Forum Members Posts: 550, Visits: 27K	And the bag may be to stiff to conform to details like design line edges. Or the edges around the mould flange. And the bag pulls at the tacky tape, wich isn't good at all. Don't do it unless it's a flat plate. Even there you should leave a little extra film for the connectors.
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John Hansen	J John Hansen posted 5 Years Ago HOT Post Details
J Group: Forum Members Posts: 42, Visits: 232	+x Hanaldo - 2/17/2019 7:24:19 AM No, it's not ideal. The bag stretches under full vacuum. When you infuse and the resin fills the cavity, the bag is no longer under full vacuum. This means the bag slacks back off, and there is more space for resin to flow into, creating a more resin rich part. In practice, it might not end up extremely resin rich and is probably acceptable for a lot of people, which is why you will see videos of people doing it. But for the sake of a few pleats, why not get the actual performance benefits of infusion? Thank you @Hanaldo. This gives me a better understanding of the process. As you mention "you will see videos of people doing it". This is exactly the issue with many of the YouTube videos on this subject. The differences between the techniques that are presented are not well explained and I am trying to sort out the real science behind the infusion process. A Lifelong Learner
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John Hansen	J John Hansen posted 5 Years Ago Post Details
J Group: Forum Members Posts: 42, Visits: 232	+x oekmont - 2/17/2019 8:52:51 AM And the bag may be to stiff to conform to details like design line edges. Or the edges around the mould flange. And the bag pulls at the tacky tape, wich isn't good at all. Don't do it unless it's a flat plate. Even there you should leave a little extra film for the connectors. Thank you oekmont. Have you seen any videos that teach the best techniques for pleating? At this time, I have been unable to find any videos that teach the best practices for pleating. A Lifelong Learner
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oekmont	oekmont posted 5 Years Ago HOT Post Details
Group: Forum Members Posts: 550, Visits: 27K	My best tip: use the tacky tape on the bagging film and leave the separation film on it for now. Than attach it to the mould, starting with the edges. Only remove the separation film where you are working. put down the middle of each edge. Maybe shift it a little, if the part isn't symmetrical and you need more film on one side. Than put down the middle of each remaining section. Repeat this, till you are down to about one point every 10cm. Remove the separation film from each remaining section separately, and make a pleat out of the section. This will happen automatically, so no needs to plan ahead, or problems with getting the tape into tiny pleats. Far easier than attaching the tacky tape to the mould imho.
	Reply Like 2
John Hansen	J John Hansen posted 5 Years Ago HOT Post Details
J Group: Forum Members Posts: 42, Visits: 232	+x oekmont - 2/17/2019 7:38:20 PM My best tip: use the tacky tape on the bagging film and leave the separation film on it for now. Than attach it to the mould, starting with the edges. Only remove the separation film where you are working. put down the middle of each edge. Maybe shift it a little, if the part isn't symmetrical and you need more film on one side. Than put down the middle of each remaining section. Repeat this, till you are down to about one point every 10cm. Remove the separation film from each remaining section separately, and make a pleat out of the section. This will happen automatically, so no needs to plan ahead, or problems with getting the tape into tiny pleats. Far easier than attaching the tacky tape to the mould imho. Thank you, your explanation was helpful. A Lifelong Learner
	Reply Like 2

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With 300%+ elongation for Bagging Film, are pleats needed for CF parts with modest (limited) depth?

With 300%+ elongation for Bagging Film, are pleats needed for CF parts with modest (limited) depth?

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