Sandwich question

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Sandwich question

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Ngood	N Ngood posted 5 Years Ago HOT Topic Details
N Group: Forum Members Posts: 3, Visits: 20	Hello, i’m new to composites and i am making a kiteboard. I bought some pvc foam from easycomposites and have glued two sheets together a 20mm sheet and a 3mm sheet to give my required thickness. I used gorilla glue and applied it all over in a zig zag pattern. The bond is good apart from the edges where there are some bits that are lifting as they didnt have glue. I plan to vacuum laminate with carbon cloth and then apply a epoxy coat to finish. I am hoping that because i’ve got good bonding overall and because its the same material sandwiched together and i’m laminating around the edges it wont delaminate later. What do you guys think? should i do something to remedy or just crack on? thanks! Edited 5 Years Ago by Ngood
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Lester Populaire	L Lester Populaire posted 5 Years Ago HOT Post Details
L Group: Forum Members Posts: 311, Visits: 13K	+x Hanaldo - 9/6/2020 12:45:19 AM There's nothing wrong with bonding core sections together to create a custom thickness core, but getting it void free is critical - any voids will create a massive weak spot under shear stress. Normally you would just coat both pieces of foam with laminating epoxy, and vac bag them together. This is very reliable and easy. I do feel Gorilla Glue is going to cause you problems here. Perhaps still worth giving it a go, as maybe there won't be enough shear stress in its application that it will fail, but on the other hand - the foam is the cheap part of a sandwich laminate. Perhaps worth starting again before putting too much more into it? Maybe just get rid of the 3mm layer with a router and glue on another layer. And when you already glue on a 3mm layer anyway you could think about a layer of carbon or glass between the foam layers and form a micro sandwich that has a high bending stiffness and you could therefore maybe get away with a lighter foam for the base layer. Probably not gonna make a big difference as your board doesn't have as much volume as a wave board tho.
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