Structural Carbon over foam skinning

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Structural Carbon over foam skinning

Author	Message
Fasta	Fasta posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	I have made quite a lot of foils for boats using all sorts of techniques. If this part is loaded where that angle is trying to open up then you can imagine there will be quite force trying to peel apart the two sides right on the bend so if that were the case then I would not recommend just gluing two halves. Ideally for me I would use pre pregs with split metal moulds and an internal bladder, vac bag or silicone intensifier. If you had a suitable foam core shaped up you could also use this with a pre preg layup and vac bag/cook. Maybe do most of the layup first and cook, then give it a smooth up and add one more final cloth for a nicer cosmetic finish. Fastacraft Facebook page
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ChrisR	ChrisR posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 363, Visits: 3K	Where's f1rob when you need him! You haven't mentioned how big the part is so any advice will be purely just general ideas and advice. i.e. It's a big of an exaggeration but if it's an aerofoil for a hydroplane 4m long and 1m deep then the advice will be completely different than if you are making a 200mmx50mm radio controlled plane wing. In fact, you may want to look at how model plane foils are built, they use a mylar wrap sometimes to provide good compression and a smooth surface, then bag it up I've seen sailboat rudders made using a 2 part mould, laid up and cured separately then the moulds are joined and 2 part foam poured into the void. Without more details they there are 3000 ways to skin a cat
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Hanaldo	Hanaldo posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Again, depends on the dimensions. I infuse 4" internal diameter intake pipes in one shot, though this is about as small as I would go when infusing. Any smaller and removing the consumables becomes near impossible. Making each half separately is an option, it just depends what sort of forces this part will see and how good a bond you can get. Obviously if you need to fill the part with foam then you can't make a bond joggle, so you will be relying on the laminate thickness as a bonding surface. If your laminate wall is smaller than 3mm then I would say it may be insufficient, but again that depends on how structural this part actually is. What is the part for, perhaps then myself or someone else can offer a bit better advice?
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jamesw	jamesw posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 61, Visits: 558	The shrink tape is a good call! I guess the "correct" method is a split mould, but it'll probably need to be pre-preg to lay it up given the dimensions... Two moulds and bonding the parts I guess should be strong enough? James
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Hanaldo	Hanaldo posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	You will need to get some sort of consolidation onto the fabric, but I've always found vacuum bagging this sort of shape in male form to be quite difficult. The bag will want to grab the excess fabric and pinch it, eliminating and chance you've got at getting a cosmetic finish on it. Have you considered the idea of producing a female split-mould of the part, laminating your carbon fibre in that (depending on dimensions of the part, this could even be done in one piece if this ends sections are open), allowing that to cure and then pouring a structural 2-part polyurethane foam inside the cavity? This to me would seem the ideal way to get the best strength and the best cosmetic finish, but it doesn't depend on the dimensions of this part. If it's a very small part then it would be quite difficult to laminate in this fashion. If you were going ahead with the method that you described with the milled male foam, then I would suggest a simple wet lay and shrink tape approach. This won't give you the ultimate in strength, but shrink tape does give you a good level of consolidation and you'd be surprised how strong a wet-layed part made in this fashion can be. You will need to do a bit of clean up work and apply a clear coat to get a good cosmetic finish though.
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jamesw	jamesw posted 9 Years Ago HOT Topic Details
Group: Forum Members Posts: 61, Visits: 558	Have some weight bearing aerofoil shaped supports to make, which will have metal milled inserts bonded in for the hardpoints at each end. I can 3D mill the foam core, has anyone tried carbon skinning in an application that requires some strength? Would I be best doing it under a vacuum? Could I infuse? How would I ensure a cosmetic finish (I guess at the very least it'll need flatting back plus lacquer) Any experiences/tips would be great to hear! Edited 9 Years Ago by jamesw
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