Back to Basics.,.Pleats Question

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#1

Hey guys,
I’m going back to the basics. I was wondering how you all determine where to put pleats? i know it says to put pleats at complex curves, but can anyone show me an exmaple? I’ve been kind of random,y putting pleats only on one side of my vacuum bag. Am I suppose to put a pleat opposite to where the other pleat is so the bag is uniform. Sorry for maybe a dumb question but…

  1. Idk where I should put pleats.

  2. Making pleats on one side scrunched up the bagging material causing the other side to have creases that’s causing air leaks that I need to patch up.

Thanks

#2

I think it is a good idea to put matching pleats opposite each other as this works out better. If one bag side is applied shorter than the other then you will get diagonal tight bits which defeats the purpose of having some loose bag to use.

Flat parts needs may need no pleats and then sections of a mould with more depth will need more bag.

#3

I put pleats where there is a thickness change, step or change in direction, I aim for a pleat the same height as the thickness change. Also in the corners. On flat plates I still put pleats along all sides as “stress relievers” in the bag.

When autoclaving if there is too much tension in the bag, the heat will soften the tacky tape and the bag may slide creating a hole.

#4

MOke is absolutely right.

Even a flat panel should have pleats, especially for infusion.

pleats go anywhere there is an elevation change or corner. Generally pleats should be symetrical in a bag. LIttle parts are pretty easy and forgiving. I’ve done some 30ft long parts that are a major pain. You gotta think about it, measure, and then add enough for your pleats but, too much is ok, too little is a new bag.

To make a bag I usually put my selant tape on the bag, then take the bag to the part. You can put the tape on the part but, I find it’s a bit harder to make a good bag this way. Once I get the bag over to the part, I start with the corners, tack them down. Usually I’ll make a baby pleat at the corners to give wiggle room, avoid tigh corners and give a spot for a vacuum probe. Then I’ll pull up the bag and find the middle, tack the middle down. Then just work the excess into where you want your pleats.

ONe tip is to trim off the excess bag that hangs over the sealant tape after you put the tape down. It sucks when the bag curls over and sticks to itself.

It just takes a bit of thought and practice and bagging is easy, fun even!

#5

For something so simple, I must need major help. Every time I make pleats, it provides a slight air pocket where the bag folds up causing the resin to leak into their during infusion and causing major bubbling as the resin flows through that area. I think I need more practice…

#6

practice makes perfect… I wish I could give you a class. Maybe I can crash on your couch? Hawaii sounds like a good field trip! :smiley:

and it is simple but, there so is riding a bike right? just be careful and take your time. Be sure to seal all pleats down to the end and where the pleat meets the tool surface. It’s a basic skill that you need if you plan on continuing with composites. You’ll get it after a while.

#7

Make your piece of sealant tape longer than the intended pleat. That way it will double back on itself when the pleat is made and seal the top of the pleat.