Years ago I costed out a mower deck for a major mower manufacturer. And today they are still fabricating them from steel. So there's your cost answer. If you want a smooth curvy deck that's a different matter. Today, Kevlar with vinyl ester resin will beat epoxy in impact resistance. Use woven E glass for structure. Add coremat fabric to the middle of the laminate stack to add thickness and reduce weight. But Chris points out the big problem. A crash becomes catastrophic as there is little flex...
I like the battery box idea. I built several for city buses years ago. Bulletproof construction for very heavy batteries. It's the top edge that requires special treatment to avoid cracking. You have to have a bit of a return on it or add linear roving around it. What would this be worth to people? In primer grey for painting the color of your choice of course.
Should the rear fenders be molded as part of the battery box? Or is impact a concern there as well?
Sent from my iPad
Sent from my iPad
On Wed, May 28, 2014 at 9:09 AM, David Roden <etpost drmm net> wrote:I'm far from an expert in these things so this might be total pie in the
sky, but I wonder whether it'd be possible to pull a mold from one of these
decks and make a new one from some kind of composite material.[Keep forgetting a reply to this list is different...]I've considered doing that myself. It would take some experimentation to get a proper solution. The composite material and thickness would have to contain anything a blade could turn into a projectile, or you'd have to require the metal blade guards (which also act to stiffen the deck).There's also the matter of getting the right amount of flex. It's easy to stiffen it up with an external framework so it doesn't fracture when you back over roots, get hung up on border stones, etc. But if it's stiff enough for that you'll need heavy equipment to straighten it out after the bigger graunches. (I've lost count of how many times I've straightened mine.) So the trick is to make it strong enough on its own to flex and spring back under typical "oops" moments. And still contain shrapnel. (The "Oh $#!+" events will require some 'glass, resin, a grinder and some time.)If anyone wants to try this I'd guess at a thickness of 3/16" to 1/4" using fiberglass with a couple layers of Kevlar (which means you need epoxy resin). Not sure how you'd do your ballistic testing. At that thickness you'd be over the weight of steel, but not by a whole lot.So this brings me to a question I've asked before about composite rear battery boxes. If I was to manufacture a composite mower deck shell, would people buy it? Just like the battery box, it would be comparable in price to steel, but offer some advantages.Chris
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