Thanks Will, great summary. Ken H.
On 2 March 2014 18:05, Will Harris <[email protected]> wrote: > I'll take a shot at answering some of the questions in a general way: > > The bits and pieces= > > Gelcoat - gives a finished outer surface and makes the part easier to get > out of the mold > > Fibers - The fibers are what give strength to the part. The engineers > have gotten very clever to matching the type, amount and orientation of the > fibers to realize the best strength to weight ratio > > Resin- The resin is only there to hold the fibers in orientation. Resin > does not add strength on its own really. > > Core- The core separates two thin skins. The skins can be a lot lighter, > and stiffer working together across a core. > > A good laminate- > > A good laminate comes from: > > Good engineering. Really, this is the key. After it, it is just > execution. Getting the right fiber, orientation, resin, resin ratio, Core > and cure is probably 80% of the game. If you have a crappy recipe, you get > a crappy cookie. > > Fibers - There are a few basic fibers used commonly in boatbuilding. > Glass, Carbon and Kevlar. There are all sorts of different types, weaves > and delivery systems with in each group. Kevlar is receding in popularity. > > Cores - There are 3 main cores - Balsa, foam, honeycomb. Basically, they > go in that order for both cost and performance. The core needs to be > strong enough to resist the sheer forces of the two skins trying to go > opposite directions. Most of the time when the Volvo boats have big delam > issues, it is because the core sheered. The right thickness of core is > important. Too thin, the boat will not be stiff. Too thick, you add > weight and $$ for nothing. > > Resins - Polyester, Vinylester, Epoxy. Again, performance tracks price! > Poly is cheap. It is the most brittle too. Epoxy is awesome stuff. One > of its best properties is that it is the most flexible. Sounds > counter-intuitive but that is good. In poly, little microscopic cracks > form because it is brittle. This lets the fibers move a little in relation > to each other and the boat gets softer overtime. > Vinylester is right between. We like it a lot because it shares many of > the good properties of epoxy, it easy to work with and is a bit less > expensive than epoxy. A bonus is that Polyester gelcoat sticks to it just > fine! > > Resin to Fiber ratio - Too much resin in the laminate is a common issue. > It seems like you would just slather it in there, but you'd be wrong. > Each system has an ideal resin/fiber ratio. Too much resin does two > things; 1- Adds weight- remember, resin is not very strong. 2- makes the > laminate weaker! Remember those micro-cracks. The are cracks in the > resin. We want the fibers nice and tight with just enough resin to hold > them in place. > > Compaction- As discussed a second ago, we want the fibers nice and > squished together. Air voids are hard to eliminate, but must be minimized. > They weaken the laminate a ton. > > Building Process - Wet lay-up, infusion, pre-preg. Again in > $$:performance. Assuming we are using female tooling. In wet layup, the > cloth is put in the mold dry and wet out and compacted with rollers. Fast > simple cheap. Your boats were made this way. > > Infusion- In the infusion method, all the fiber, core etc are put in the > mold dry. Then we stick a vacuum bag on it with very strategically placed > resin inlets and exhausts. We draw the vacuum, and get the laminate really > firmly consolidated. Then, a metered amount of catalyzed resin is > introduced through the ports. Getting the ports place right is really > important to draw the proper resing front through the part. When the > correct amount of resin is injected, the vacuum stays on until the part > cures. This gives us really good control over both the resin ratio and the > consolidation. > > Pre-preg - carbon comes from a laboratory with a heat setting epoxy > already in the fiber. This is placed in the mold, a vacuum applied and it > is cooked in a oven. First, the heat melts the glue and lets it flow. > Then the heat is kicked up a notch and that sets off the cure cycle. > There is a really specific protocol for ramp up, cure and ramp down temps. > If you really like spending, the oven can be an autoclave with increases > the pressure to about 6 ATM as opposed to the 1 possible with an ambient > bag. > > This is the highest performance option, but stupid spendy. Our little 30 > footer could come out a the $330 - $400 K range. Ouch. > > That is a short ( for an overview), but long ( for a mail list ) run down > of modern boat building. If you have specific questions; fire away. > > Come to the Open House! We will be running infusion demonstrations, and > the smart guys will be able to explain anything to you. Plus, you can > heckle Andy and get a free lunch. > > Will > > > > > > > -- > Will Harris > Waterline Systems > > 716-531-6088 > > > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > [email protected] >
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