Finishing off ruff part (Hydro foil)

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Finishing off ruff part (Hydro foil)

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PAYBACK	PAYBACK posted 13 Years Ago HOT Topic Details
Group: Awaiting Activation Posts: 4, Visits: 65	Hi Guys Busy finishing off a Stand-up Hydrofoil I've been busy building. Got all the basic components finished and I'm in the process of finishing off a very critical part which is the mast. Core material is AIREX that has been shaped by hand on a router carriage with a NACA 63012 profile. This part has to be extremely stiff with little to no flex over the 1000mm x 80mm x 12mm piece. It mates the fuselage with the board. I vacuum bagged a combination of aramid (carbon/kevlar) plain weave and uni-directional carbon fiber onto the piece about 5 layers a side. I've now started laying up carbon tows in a 45 degree pattern both sides of course and alternated them. Almost got the desired stiffness I need, might do this twice. Of course this has left piece a bit uneven. I should have done it first then laid ontop of that to hide the imperfections but I wanted to have some meat on the core first to work off, there was not much core to start off with in the first place due to the profile being so slim. I will be adding a final "glamor" layer of 200g twill to finish it off but it wont totally hide the imperfections and add final stiffness. What would be the best method to get a totally smooth final surface in this scenario? I thought about building up a few thickened (Fumed Silica) resin layers sanding smooth then adding final twill layer, but it adds weight and is time consuming. Anyone have a better idea? Below is picture of surface. Still need to clean it up but you get the idea.
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PAYBACK	PAYBACK posted 13 Years Ago HOT Post Details
Group: Awaiting Activation Posts: 4, Visits: 65	Wrong forum?
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fgayford	fgayford posted 13 Years Ago HOT Post Details
Group: Forum Members Posts: 433, Visits: 1.2K	There is no easy way out of this. I would use glass micro balloons mixed with epoxy. Mix in the balloons until it will not run and put it on the roughed up surface like bondo. When cured it will not add hardly any weight and is easy to sand. Once faired seal the areas you applied the mixture with epoxy. Now rough it up and apply your carbon coat in the same manner as the skinning video here on this sight. Fred
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