Vacuum bag corner voids

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Vacuum bag corner voids

Author	Message
grafgulch	grafgulch posted 10 Years Ago HOT Topic Details
Group: Forum Members Posts: 4, Visits: 63	Hello all, Can anyone tell how I can eliminate the voids I get aroundthe edges/corners of my foamcore during a vacuum bag lay up? My layup is a lamination of fiberglass, wood, foam core & carbon fiber. I believe my all my layers are wetted outcompletely before they are placed on the mold. I use a peel ply & bleedermaterial before putting on the bagging film. Attached is picture one of the problemareas. TIA, Paul Attachments badvac.PNG (510 views, 2.00 MB)
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ChrisR	ChrisR posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 363, Visits: 3K	Hi, you can prevent/reduce bridging by gathering (lots of little pleats) the vac bag as you it goes around the corner, this allows the bag to conform to the shape. You also need to work the fabric into the internal corners a bit more, if it's not worked in it will not go in once you apply the vac bag Not the clearest picture but should give you an idea
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grafgulch	grafgulch posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 4, Visits: 63	Thanks.. I will try that. I know sometimes my bagging film is pulled kind of tight. I do use a very thin bagging film with lots of stretch. Visually, the bagging film looks like to conforming to all the inside corners very well. I guess my next question is: Whats the best way to fix these voids? normally my next step is to apply 2 layers of very lightweight cloth (1.45 oz deck cloth) with the vacuum bag applied directly to the part (with bleeder material on the side) to produce a smooth glossy finish. If I use lots of pleats on the next step I am afraid I won't get a smooth finish. I am thinking I need to fix these voids before the next step, otherwise I won't get the nice smooth finish at these problem areas. Paul
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Hanaldo	Hanaldo posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Just fill them with a bit of resin and then sand flat.
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Matthieu Libeert	Matthieu Libeert posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 955, Visits: 3.4K	are you using a perforated film on top of your peelply? Matthieu Libeert Founder MAT2 Composites X Sports website: www.mat2composites.com
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grafgulch	grafgulch posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 4, Visits: 63	No, I am just using peel ply with poly bleeder material to soak up the excess epoxy resin. The bleeder material I use is just poly batting from the fabric store. Here is a link to the peel ply that I use: http://aircraftproducts.wicksaircraft.com/item/vacuum-bagging/release-fabric-ply-blb1/blb-1?
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scottracing	scottracing posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 460, Visits: 5.2K	as matthieu has asked I would use a perforated release film, as your bleeder cloth will be soaking up too much resin causing dryspots in your part. Plus when you vacuum the part down use a dibber to maniuplate the bag into the tighter corners, its better to have more bag than no bag as you will inevitably get bridging.
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Matthieu Libeert	Matthieu Libeert posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 955, Visits: 3.4K	you do need a perforated flm to avoid to much resin being sucked out of the part Matthieu Libeert Founder MAT2 Composites X Sports website: www.mat2composites.com
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Zorongo	Zorongo posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 40, Visits: 330	From my point of view, there are no dry spots or dry edge (agrreing to your information). The different shine is owed to the PEEL PLY´s bridging. Then, you'll have to work the peel ply better, addapt it to the radius. Cut it when needed. It´s a common problem on the radious. You can cut it in two pieces, one of them for the flat area and another one for the side. As much times as needed. For a "box" piece, you can make one pp for the flat area, two or four for the sides, and one (or no) for the top horizontal, as you could do two parts, for opposite sides covering also upper vertical.... try it, works well. Peel plies together must overlap. Using that arrangement, peel ply can slide a bit and will adapt to edges and radious. Is the common solution. More work, but better results. (.... and good luck !) Edited 10 Years Ago by Zorongo
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grafgulch	grafgulch posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 4, Visits: 63	Thank you all for the great advice. Zorongo, I think you are on to something regarding the peel ply. Paul
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